giao trinh_chat hoat dong be mat

8/10/2019 GIAO TRINH_chat Hoat Dong Be Mat

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PGS.TS. L TH HNG NHAN_CNG NGH CHT HOT NG B MT 1

Trng i Hc Bch Khoa-i Hc Quc Gia TP H Ch Minh

Khoa K Thut Ha Hc

B mn K Thut Hu C

CNG NGH CHT HOT NGB MT

PHN 1: TNG QUAN VCHT HOT

NG B MT

PGS.TS. L Th Hng Nhan

Tp. HCM, 2012


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MC LC

MC LC ........................................................................................................................................ 2

CHNG 1

L THUYT CBN V CHT HOT NG B MT........................... 6

1.1 SC CNG B MT V CC YU T NH HNG......................................... 6

1.1.1 Sc cng b mt......................................................................................................... 6

1.1.2 Cc yu t nh hng n sc cng b mt............................................................. 8

1.2 CC CHT HAT NG B MT, CHT KHNG HAT NG B MT V

CHT KHNG NH HNG N SC CNG B MT................................................. 9

1.3

HOT NG B MT QUY TC TRAUBE I............................................. 12

1.4

CC PHNG PHP XC NH SC CNG B MT..................................... 13

1.4.1 Xc nh s bin i mc cht lng trong mao qun ........................................... 13

1.4.2 Phng php cn git lng..................................................................................... 13

1.4.3 Phng php ko vng Lecomte du Nouy ............................................................ 14

CHNG 2

TNH CHT HA L CA CHT HOT NG B MT TRONG DUNG

DCH 15

2.1

CU TO LP B MT TRN GII HN LNG-KH ....................................... 15

2.2 SHNH THNH MICELLE ...................................................................................... 16

2.3 NNG MICELLE TI HN................................................................................ 18

2.4 IM KRAFT............................................................................................................... 19

2.5

IM C.................................................................................................................... 20

2.6 HLB (HYDROPHILE-LIPOPHILE BALANCE) ...................................................... 20

2.7 C TNH B MT LNG-RN V QUAN H B MT TRONG H BA PHA23

CHNG 3 PHN LOI V NG DNG CHT HOT NG B MT............... 25

3.1 GII THIU CHUNG.................................................................................................. 25

3.1.1

Phn loi theo bn cht nhm ho nc................................................................ 25

3.1.2

Phn loi theo bn cht nhm k nc.................................................................. 25

3.1.3 Phn loi theo bn cht lin kt nhm k nc v i nc.................................. 26

3.2 CHT HOT NG B MT ANION.................................................................... 26

3.2.1 Cht hot ng b mt ngun gc acid carboxylic............................................... 26

3.2.1.1 X phng.......................................................................................................... 26


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3.2.1.2 Cc cht hot ng b mt t acid carboxylic thin nhin khc.................. 27

3.2.1.3 Cc cht hot ng b mt t acid carboxylic tng hp.............................. 28

3.2.2

Cht hot ng b mt sulfate................................................................................ 28

3.2.3

Cht hot ng b mt sulfonate ............................................................................ 29

3.3 CHT HOT NG B MT CATION.................................................................. 31

3.3.1 Gii thiu................................................................................................................. 31

3.3.2 Mt s ng dng...................................................................................................... 33

3.4 CHT HOT NG B MT LNG TNH........................................................ 35

3.4.1

Gii thiu................................................................................................................. 35

3.5

CHT HOT NG B MT KHNG ION.......................................................... 36

3.5.1 Gii thiu................................................................................................................. 36

3.5.2 Mt s ng dng...................................................................................................... 37

3.6 NG DNG TNG QUT......................................................................................... 40

CHNG 4 KH NNG TO NH TNG ................................................................. 41

4.1

PHN LOI NH TNG ........................................................................................ 41

4.2

HIN TNG NH HA.......................................................................................... 42

4.3 CHT NH HA......................................................................................................... 43

4.3.1

Khi nim................................................................................................................. 43

4.3.2 Phn loi cht nh ha............................................................................................ 43

4.3.3 Vai tr ca nh ha trong s hnh thnh nh........................................................ 44

4.4

BN VNG CA TP HP NH TNG ...................................................... 45

4.5 IU CH V PH V H NH TNG-S O NH (O PHA)............ 46

4.6 CC BIN PHP LM BN NH............................................................................ 47

4.6.1 Cs v tnh n nh ca nh tng ..................................................................... 47

4.6.2 Cc yu t nh hng bn nh.......................................................................... 48

4.6.3

Cc bin php lm bn nh..................................................................................... 49

4.7

MT S CHT HOT NG B MT C DNG LM CHT NH HA

O/W 50

CHNG 5 CHT HOT NG B MT V CC H BT.................................... 53

5.1 BN VNG CA TP HP BT...................................................................... 53

5.2 CC NGUYN NHN LM BN BT................................................................... 54

5.3

CC TC NHN LM TNG BT (FOAM BOOTSTER)................................... 54


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5.3.1 Chn la cht hot ng b mt............................................................................. 55

5.3.2 S dng cc cht ph gia lm tng bt.................................................................. 55

5.4

CC TC NHN CHNG BT (ANTIFOAMER)................................................. 56

5.4.1

Cch ph v bt bng cc ht k nc............................................................... 56

5.4.2 Cch chy loang (spreading)............................................................................... 57

5.5 IU CH V PH V BT.................................................................................... 57

CHNG 6 KH NNG TY RA................................................................................. 59

6.1 CCH TYRA...................................................................................................... 59

6.1.1 Ty cc vt bn c cht bo......................................................................................... 59

6.1.2

Ty cc vt bn dng ht..................................................................................... 62

6.2 CC YU T NH HNG N QU TRNH TY RA................................ 63

6.3 NH GI KH NNG TY RA......................................................................... 64

6.4 CHT HOT NG B MT V CC CH TIU KHC .................................. 64

6.4.2 Kh nng to h huyn ph .................................................................................... 64

6.4.3

Kh nng thm t.................................................................................................. 65

6.4.4

Ch s canxi chp nhn........................................................................................... 65


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Hnh 1.1: B mt phn chia pha lng-kh ca mt cht lng nguyn cht................................... 7

Hnh 1.2: Quan h tuyn tnh gia sc cng b mt v nhit ................................................... 9

Hnh 1.3: S ph thuc ca sc cng b mt theo nng (ng nhit).................................. 11

Hnh 1.4: hot ng b mt ca ng ng acid formic........................................................ 12

Hnh 1.5: Phn b ca cht hot ng b mt ti gii hn lng-kh. (a) khi nng thp v (b) khi

nng ln................................................................................................................................ 15

Hnh 1.6: S hnh thnh cu trc micelle ca cht hot ng b mt......................................... 16

Hnh 1.7: Cc dng cu trc micelle khc nhau........................................................................... 17Hnh 1.8: Cc dng micelle trong mi trng nc v dung mi khc nhau. ........................... 17

Hnh 1.9: S thay i t ngt tnh cht vt l ca dung dch cht hot ng b mt khi ti im

CMC ................................................................................................................................................ 18

Hnh 1.10: H ba pha ca git cht lng nm trn b mt rn trong khng kh........................ 24

Hnh 2.1: Cu to mng bt........................................................................................................... 53

Hnh 2.2: S thay i ca si sau khi git.................................................................................... 33

Hnh 2.3: Tc ng ca cht lm mm ln b mt vi si........................................................... 33


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CHNG 1 L THUYT C BNV

CHT HOT NG B MTCc qu trnh d th bt k (nh hnh thnh hay phn hy cc cht rn, ha tan cc cht rn,

lng v kh, bay hi, thng hoa, ty ra, to nh tng, bt .) u l nhng qu trnh xy ra

trn b mt phn chia pha. Trng thi cc cht b mt phn chia pha rt khc vi vt cht trong

lng cc pha v c s khc bit v tng tc gia cc phn t vi nhau. S khc bit lm sn

sinh cc hin tng c bit trn b mt phn chia pha.

Vic nghin cu hin tng b mt c sc li cun ln v n c tm quan trng l thuyt vthc t. Nghin cu cc hin tng b mt c th nh gi c nng lng v hiu r c bn

cht tngtc phn t. ngha thc t ca cc hin tng b mt l ch, vt cht c b mt ln

rt ph bin trong t nhin v c ng dng rng ri trong k thut. V vy vic tm hiu v sc

cng b mt ng mt vai tr rt quan trng.

1.1 SC CNG B MT V CC YU T NH HNG

1.1.1 Sc cng b mt

Xt trn mt b mt phn chia pha lng- kh ca mt cht lng nguyn cht. Mi phn t cht

lng u chu s tng tc ca cc phn t bao quanh (tng tc lng cc-lng cc, lng

cc- cm ng, tng tc khuch tn- y l ba thnh phn ca lin kt Van der Waals). Tuy

nhin:

+ i vi cc phn t trong lng pha lng cc lc tng tc l cn bng vi nhau

+ i vi cc phn t trn ranh gii phn chia pha, lc tng tc v pha pha lng ln

hn v pha pha kh, nn to ra mt lc p ln phn cht lng v phabn trong. p sut to ra (lc trn mt n v b mt) gi l p sut phn t -chnh l ni p pi trong phng trnh van der

Waals. Ni p ny ko cc phn t cht lng t b mt phn chia pha, do c xu hng lm cho

b mt gim n mc ti thiu.


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Hnh 1.1: B mt phn chia pha lng-kh ca mt cht lng nguyn cht

Vy cc phn t lp b mt c th nng ln hn so vi th nng ca ca cc phn t bn

trong. Phn nng lng ln hn gi l nng lng b mt ca cht lng. Mun lm tng b

mt, cn phi phi a thm cc phn t t trong lng pha lng n lp b mt, tc l thc hinmt cng chng li lc tng tc ca cc phn t. Cng trong iu kin ngnhit thun

nghch bng tng ca nng lng d b mt dEs. Khi b mt tng mt gi tr ds th nng lng

b mt cng tng mt gi tr dEs.

dEs= ds hay = dEs/ds

Trong nng lng to ra mt n v b mt hay cn gi l sc cng b mt. Ni cch

khc: Lc tc dng trn mt n v chiu di ca gii hn (chu vi) b mt phn chia phav lm

gim b mt ca cht lng gi l sc cng b mt. (erg/cm2hay dyn/cm v 1 erg = 1 dyn/cm)

Sc cng b mt ph thuc vo bn cht ca cht tip xc.

Cht lng cng phn cc, tng tc phn t cng ln, ni p cng ln, do sc cng b mt

cng ln.

Do mt phn t ca kh hoc hi nh hn rt nhiu so vi mt phn t ca cht lng

nn tng tc gia cc phn t c th b qua c. iu ny khng th thc hin c.

S c mt trn lp cht lng th nht lp cht lng th hai khng trn lnvi n lun lun

lm sc cng b mt gim. S gim sc cng b mt cng nhiu nu s khc bit v phn cc

ca hai cht lng cng b. Cc cht lng c phn cc cng gn nhau s tan lnvi nhau cng

nhiu v do sc cng b mt gia chng s bng khng.

Nu hai cht lng ch ha tan mt phn vo nhau th sc cng b mt trn gii hn lng lng

gn bng hiu s gia sc cng b mt ca mi cht ( bo ha cht kia) so vi khng kh.

A A

B B B


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Bng 1.1: Sc cng b mt ca cc cht lng tip xc vi khng kh (o) v ca cht lng tip xc vi nc (I)

20oC (dyn/cm).

Cht lng o I Cht lng o I

Nc 72,75 - Ethanol 22,30 -

Benzene 28,88 35,00 n-octanol 27,50 8,50

Acid acetic 27,60 - n-hexane 18,40 51,10

CCl4 26,80 45,10 n-octane 21,80 50,80

Glycerin 66,00 - Anilin 42,90 -

B mt cht lng Nhit

(oC)

Sc cng b mt lng-khng

kh (dyn/cm)

Sc cng b mt lng-lng

(dyn/cm)

Lp hu c Lp nc Tnh ton Thc nghim

Benzene/nc 19 28,8 63,2 34,4 34,4

Anilin/nc 26 42,2 46,4 4,2 4,8

Di tc dng ca sc cng b mt, th tch khi cht lng s hng ti dng hnh cu (nu

khng c ngoi lc) v b mt hnh cu l b mt b nht gii hn mt th tch cht lng cho.

1.1.2 Cc yu tnh hng n sc cng b mt

a.nh hng ca nhit n sc cng b mt

Ngoi yu t bn cht ca cc pha tip xc c ngha quyt nh n gi tr sccng b mt,

sc cng b mt cn ph thuc vo nhiu yu t khc nh nhit , p sut, cong ca b mt

v c bit l s c mt ca cht th hai trong cht lng. Trong phn ny ch cp n mi quan

h gia sc cng b mt v nhit , cc yu t khc s tho lun sau.

Sc cng b mt ca a s cht lng gim gn nhtuyn tnh khi nhit tng (tr cc kim

loi nng chy) theo phng trnh ca W. Ramsay v J. Shields sau khi hiu chnh phng trnh

ca R. Eotvos:

V2/3= k (T c - T 6)

Trong :


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V: Th tch mol ca cht lng

T c: Nhit ti hn, sc cng b mt bng khng

k : hng s, a s cht lng c k 2,1 erg/

Van der Waals v ngi theo trng phi ca ng l Guggenheim cn a ra phng trnh c

dng sau:

= o(1 T/T c)n

Vi cht hu c c n = 11/9 v vi kim loi c n 1.

Ni chung quan h tuyn tnh gia sc cng b mt v nhit c dng sau:

T= - T (d/dT)

Vi (d/dT) = const.

Hnh 1.2: Quan h tuyn tnh gia sc cng b mt v nhit

b. Quan h gia khi lng ring v sc cng b mt

Theo phng trnh Mc Leod: /(D-d)4= Const

D: Khi lng ring pha lng v d: khi lng ring pha kh (g/cm3).

1.2 CC CHT HOT NG B MT, CHT KHNG HOTNG B MT V CHT KHNG NH HNG N SC

CNG B MT

Trn y kho st sc cng b mt ca cc cht lng nguyn cht, i vi dung dch, hin

tng ny tr nn phc tp hn do s hp ph. Ty theo kh nng hp ph ti gi hn lng kh

ca mt cht ha tan, c th chia lm hai loi: cht hotng b mtv cht khng hot ng b

mt.

(dyn/cm)

T (oC)


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Cc cht hotng b mtl nhng cht c kh nng lm gim sc cng b mt ca dung

mi cha n. Cc cht ny c kh nng hp ph ln lp b mt, c tan tng i nh, nu

khng chng c xu hng ri khi b mt vo trong lng cht lngCc cht hotng b mt trong nc a s l cc cht hu c nh cc acid bo, mui ca

acid bo, ester, ru, alkyl sulfate. Cc phn t cht hotng b mt bao gm hai phn:

+ Phn phn cc(i nc, a nc, ho nc) thng cha cc nhm carboxylate, sulfonate,

sulfate, amine bc bn Nhm ny lm cho phn t cht hotng b mt c i lc ln i

vi nc v b ko vo lp nc.

+ Phn khng phn cc (k nc, ght nc hay i du, ho du, a du) l cc gc

hydrocarbon khng phn cc k nc, khng tan trong nc, tan trong pha hu c khng phncc nn b y n pha khng phn cc. Phn t cht hotng b mt c biu din nh sau:

Phn i nc

Phn k nc

Cc cht khng hotng b mtl nhng cht m khi nng ca n trong dung dch tng

ln th sc cng b mt tng ln. Cc cht ny c ha tan cao, s c xu hng ri khi b mt

i vo bn trong th tch dung dch.

Cc cht khng hotng b mt so vi nc l tt c cc mui v c in ly, cc acid, base

v c. Phn t ca cc cht ny khng c phn k nc m s in ly trong nc thnh cc ion

phn cc, b hydrate ha mnh. Cc cht khng hotng b mt hu c c rt t, l nhng

cht c th ion ha v phn khng phn cc ca phn t khng c hoc rt b nh HCOOH,

CH3COOH.

Trong cc dung mi hu c, cc cht in cng lm tng sc cng b mt, mc gia

tng ty thuc vo bn cht ca dung mi. V d khi thm NaI vo CH3OH: sc cng b mt s

tng nhiu, nu thm NaI vo C2H5OH th tng ny gim 2 ln.

Ngoi cc cht hotng b mt v khng hotng b mt, c nhng cht phn b u n

trn c lp b mt v trong lng dung dch do khng nh hng n sc cng b mt ca dung

mi. V d nh ng saccarose, ha tan vo nc khng lm thay i sc cng b mt trn gii

hn lng kh.


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Hnh 1.3:S ph thuc ca sc cng b mt theo nng (ng nhit)

C th nhn thy khi tng nng cht hotng b mt, lc u sc cng b mt gim

mnh. Do lc u mt lng nh cht hotng b mt c trong dung dch hu nh di chuyn

ht n b mt, do th tch ca lp b mt nh hn rt nhiu so vi th tch ca pha lng, nn ch

c mt lng nh cht hotng b mt cng s lm thay i rt ln sc cng b mt. Tip theo

nng trungbnh ca cht hotng b mt, sc cng b mt tip tc gim nhng chm hn

do phn ln b mt b chim ch. nng ln sc cng b mt t ph thuuc vo nng .

i vi cht khng hotng b mt, do c tan ln nn cc phn t cht khng hotng

b mt lun c xu hng ri khi b mt i vo lng dung dch, lm tng sc cng b mt.

Trn gii hn lng kh ch c mt lng nh cht khng hotng b mt nn sc cng b mt

tng chm.

i vi cht khng lm thay i sc cng b mt ca dung mi th ng ngnhit l mt

ng thng song song vi trc to .

Lu :

Tnh hotng b mt ca mt cht khng ch ph thuc vo bn cht ca n m cn ph

thuc vo mi trng cha n (dung mi). Nu dung mi c sc cng b mt cao th cht

cho c th biu hin tnh hotng b mt cao. Tuy nhin nu dung mi c sc cng

b mt thp th cng chnh cht y li khng c tnh hotng b mt. V d: mt s cht

c tnh hotng b mt vi nc nhng khng c tnh hotng b mt trong ru.

Trong k thut thng dng nc lm dung mi. chng trnh ny ch kho st cc

cht hotng b mt trong mi trng nc.

2

3

1Nng

Sc cng b mt

1: Cht hot ng b mt 2: Cht khng hat ng b mt3: Cht khng nh hng n sc cng b mt


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Sc cng b mt ca cht lng nguyn cht gn nh gim u n khi nhit tng cn

dung dch cha cht hotng b mt c th l mt ng biu din c cc i. im cc

i c gii thch l trong mt khong nhit nht nh, xy ra s gii hp ph cc chthotng b mt trn b mt lng- kh, dn n s gia tng sc cng b mt trong khong

.

1.3 HOT NG B MT QUY TC TRAUBER I

hotng b mt -d/dc l bin thin sc cng b mt theonng cht hotng b

mt cn gi l i lng Gibbs -d/dc = G*.

hotng b mt ca cc cht trong dy ng ngbin i c quy lut. V d nh trong

dy ng ngacid c 6 nC2 khi nng tng ln, sc cng b mt ca acid m trong phn

t c mch carbon di hn s gim nhanh hn. Hin tng tng t cng xy ra cc dy ng

ng khc.

C, mol/l

, dyn/cm

(1)

(2)

(3)

35

50

65

0,16 0,36 0,54

(4)(5)

(1)HCOOH(2) CH COOH(3) CH CH COOH(4) CH (CH ) COOH(5)(CH ) CHCH COOH

3

3 2

3 2 2

3 2 2

Hnh 1.4: hot ng b mt ca ng ng acid formic

Trn c s thc nghim DuclauX J v Trauber I tng kt thnh quy tc thng gi l quy

tc Trauber I: hotng b mt tng ln t 3 n 3,5 ln khi tng chiu di mch carbon

ln 1 nhm CH2. Quy tc ny l c s tng hp cc cht hotng b mt c hot

ng b mt theo yu cu.


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1.4 CC PHNG PHP XC NH SC CNG B MT

Cc phng php ph bin xc nh sc cng b mt l:

1) Xc nh s bin i ca mc cht lng trong mao qun

2) Cn git cht lng

3) Phng php Lecomte du Nouy

4) Bn phng L. Wilhelmy

5) p sut cc i ca bt kh

6) Xc nh hnh dng ht v bt kh

1.4.1 Xc nh s bin i mc cht lng trong mao qun

y l mt trong nhng phng php chnh xc nht xc nh sc cng b mt

Nguyn tc o: o chiu cao ct cht lng trong mao qun

P = P1 P2= gh (1-2) = 2/r

: gc dnh t, cos= Ro/r

Ro: bnh knh ca mao qun, r bn knh mt khum ni tip xc

P1v P2: p sut phakh trong v ngoi ng mao qun

Suy ra = (1/2) (Rogh (1-2) / cos

1.4.2 Phng php cn git lng

y l phng php kh chnh xc, c s dng ph bin trong phng th nghim xc

nh sc cng b mt trn gii hn lng kh v lng lng.

Nguyn tc o: thu cc git lng hnh thnh di mao qun, cn xc nh chnh xc khi

lng mt git bng phng php ly trung bnh.

Biu thc ton (nh lut Tate T) c dng n gin sau:

W= mg = vg = 2Ro

Nguyn nhn c s xut hin sc cng b mt l lc cc i gi git cht lng chnh bng

sc cng b mt gy ra trn ton chu vi. Tuy nhin c sai s l khi lng cn c thng nh

hn gi tr l tng do tnh khng bn ca cc ui git lng v lun lu li u mao qun

n 40% khi lng.


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Harkins W.D. v Brown F.E. ngh hiu chnh w theo phng trnh sau

w = mg = vg = 2Rof*

Trong f* = (R0/v1/3) : h s hiu chnh

V: th tch git

Suy ra: = vg / 2Rof*

1.4.3 Phng php ko vng Lecomte du Nouy

Phng php ny c xut nm 1919.

Nguyn tc o: xc nh lc ko vng kim loi ra khi b mt cht lng

Wk= 4Ro = f (*)

Wk: khi lng ca vng, f l lc ko vng (dyn)

khc phc sai s th a vo h s hiu chnh * (b tr bin dng mt phng khi ko

vng, h s ny l hm ca (R3/V, Ro/ro)

* = / = f(R3/V, Ro/ro)

: sc cng b mt c tnh theo phng trnh (*)

V: Th tch b mt cong

ro: bn knh ca tit din vng

R0: bn knh ca vng

H s hiu chnh * c th tra trong s tay v sc cng b mt hoc da vo th Harkins

W.D, Jordan H.F., cng c th tnh c * theo phng trnh Znidema- Waters

(* -a)2= (4b/ 2).(1/R2).(f/(4Ro.(1- 2))) + c

1v 2khi lng ring ca cht lng di v trn vng

a = 0,7250 v b = 9,075 . 10 -4i vi mi loi vng

c = 0,04434 1,679 ro/Ro


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CHNG 2 TNH CHT HA L CA

CHT HOT NG B MT TRONGDUNG DCH

2.1 CU TO LP B MT TRN GII HN LNG-KH

tm hiu cu to lp b mt trn gii hn lng kh ngi ta tm hiu mi quan h gia

hp phv nng C ca cht hotng b mt c trong mt n v din tch b mt. Kt qu

cho thy s hp ph tng t l vi chiu di mch carbon trong mt dy ng ngv cc ng

ny t gi tr gii hn khi nng cht hotng b mt ln.

Nh vy nng ln, mt n v b mt s cha cng mt s lng phn t cht hot

ng b mt c chiu di phn k nc khc nhau, ngi ta gii thch iu ny nh sau: khi b

hp ph, nhm phn cc ca cht hot ng b mt b nc ko mnh vo lng dung dch, phn

khng phn cc th b y ra pha pha khng phn cctc phakh, cc phn t cht hot ng b

mt s c phn b thnh mt lp phn t. Khi nng C nh, mch hydrocarbon s b y v

pha khng kh, c th b ng nghing do mch hydrocarbon linh ng v c khi lng ring b,

phn phn cc trong nc. Khi nng C ln, s phn t cht hot ng b mt tng ln, mch

hydrocarbon dng ng ln, song song vi nhau, vung gc vi mt nc, to thnh mt mng

st cht gi l mng ngng t. Cc phn t cht hot ng b mt s chim cng din tch d cho

chng c chiu di khc nhau.

Hnh 2.1: Phn b ca cht hot ng b mt ti gii hn lng-kh. (a) khi nng thp v (b) khi nng ln


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2.2 SHNH THNH MICELLE

Trng thi cc cht hotng b mt trong dung dch c kho st trn mui ca acid bo

(x phng). Tnh cht ca cc cht hotng b mt khc cng tng t.

Thc nghim cho thy trong dung dch, x phng c th tn ti di dng cc phn t khng

ion ha RCOONa, ion RCOO-v Na+, cc sn phm do thy phn RCOOH, dng tp hp cc

phn t khng ion ha, cc ion v cc acid bo: xRCOONa.yRCOOH.zRCOO-.zNa+.

Khi nng cht hotng b mt tng ln mt gi tr no , t cc phn t ha tan ring

bit, mt s ln cc micelle bt u hnh thnh trong h. Cc micelle ny l cc hnh cu trong

cc phn t cht hotngb mt lin kt vi nhau bng u hydrocarbon v hng nhm phn

cc ra dung dch nc.

Hnh 2.2: S hnh thnh cu trc micelle ca cht hot ng b mt

S phn t x phng trong mt tp hp nh vy vo khong 50, ng knh hnh cu

khonggp i chiu di phn t x phng to nn n. Ngi ta gii thch s to thnh micelle

nh sau:

+ Do lc ht Van der Waals gia cc phn hydrocarbon k nc, do lc y ca cc nhm

tch in cng du.


17/66


+ Do lc ht gia cc phn t nc, cc phn t nc s y mnh hydrocarbon k nc ra

khi dung dch v do lm cho chng phi lin kt li vi nhau.

cc nng cao hn, cc micelle c kch thc tng ln v cc gc hydrocarbon mi lcmi thm song song vinhau hnh thnh cc micelle tm hay cc hnh dng khc.

Hnh 2.3: Cc dng cu trc micelle khc nhau

Cn lu rng cc micelle c th c to thnh khng ch trong cc dung dch nc m cn

dung dch x phng trong dung mi. Khi cc phn t x phng trong micelle s hng cc

nhm phn cc vo pha trong micelle cn phn k nc s quay ra ngoi. Lc ny x phng

khng in ly, dung dch x phng l dung dch phn t ch khng l dung dch ca cc ion.

Hnh 2.4: Cc dng micelle trong mi trng nc v dung mi khc nhau.


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2.3 NNG MICELLE TI HN

Khi nng cht hotng b mt tng ln n mt gi tr no , t cc phn t ring ls c

s hnh thnh cc micelle. Nng dung dch cht hotng b mt m s hnh thnh

micelle tr nn ng k gi l nng micelle ti hn (CRITICAL MICELLE

CONCENTRATION).

Khi nng dungd ch cht hotng b mt t n gi tr CMC, s c s thay i r rt

tnh cht vt l ca dung dch nh s thay i c, dn in, sc cng b mt, p sut thm

thu.. Da vo s thay i tnh cht vt l t ngt nh vy ngi ta xc nh cCMC.

Hnh 2.5: S thay i t ngt tnh cht vt l ca dung dch cht hot ng b mt khi ti im CMC

*Cc yu t nh hng n CMC:

+ Khi tng chiu di ca phn k nc trong phn t cht hotng b mt s to iu kin

thun li cho s hnh thnh micelle, tc l gim CMC. Trong mi trng nc ct, CMC ca cc

cht hotng b mt ion gim i ln khi mch carbon tng thm 1 nhm CH2- . i vi chthotng b mt khng ion, s khc bit ny cn r rng hn, iu ny ng n C16. Khi mch

C 18 th CMC hu nh khng i.

V d: CMC ca cht hotng b mt alkyl sulfate Natri trong nc 40oC

S nguyn t C 8 10 12 14 16 18

CMC x 103mol/L 140 33 8,6 2,2 0,58 0,23

p sut thm thu

c

Sc cng b mt

dn in

Nng CMC


19/66


+ Khi h nhit dung dch, s xc tin cho s hnh thnh ca cc micelle v khi cng

chuyn ng nhit ca cc phn t gim, lm tng kh nng kt hp ca cc phn t tc l m

gim CMC.+ Khi thm cht in ly vo dung dch cht hotng b mt, chng lin kt vi nc do s

hydrate ha, iu ny tng t nh vic tng nng cht hotng b mt ln. Mc khc, khi

c mt cht in ly, s ion ha ca cht hotng b mt gim (gim tan), xc tin cho s lin

kt cc phn t li vi nhau, do CMC gim.

V d: CMC ca lauryl sulfate natri trong dung dch NaCl 25oC

Nng NaCl

(mol/L)

0 0,01 0,03 0,1 0,3

CMC x 103mol/L 8,1 5,6 3,1 1,5 0,7

+ Vic thm cc cht hu c vo dung dch cht hotng b mt nh hng n CMC theo

nhng hng khc nhau ty thuc vo bn cht ca cht thm vo. Mt s ru mch trung bnh

c th lm gim CMC, thm urea hay formamide li lm tng CMC. Dung dch cha nhiu cht

hot ng b mt c CMC nh hn CMC ca cc dung dch cha tng cht hot ng b mt

ring bit.

2.4 IM KRAFT

Cc cht hot ng b mt anion c mt c im l kh nng ha tan ca chng tng theo

nhit .im Kraft l nhit ti cht hot ng b mt c ha tan bng CMC. Khi t

n nhit ny mt lng ln cht hot ng b mt s c phn tn trong dung dch di

dng micelle. Nh vy nhit thp hn im Kraft, tan ca cht hot ng b mt anion

khng ln hnh thnh micelle. Khi nhit tng, tan tng, khi t n nhit Kraft,

micelle hnh thnh. i vi cht hot ng b mt anion, khi chiu di mch C tng, im Kraft

cng tng.

Bng 2.1: im Kraft ca dung dch alkyl sulfate trong nc

S nguyn t C 10 12 14 16 18

im Kraft (oC) 8 16 30 45 56

Lu rng cc gi tr ny c th thay i khi c mt ca cc thnh phn khc.


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2.5 IM C

i vi cc cht hot ng b mt khng ion, tan ca chng l do lin kt hydrogia nc

v phn phn cc (chui polyoxyethylene). Khi nhit tng n mt mc no , lin kt hydro

b ph v, xy ra s mt nc, lm tan ca cht hot ng b mt khng ion gim. im c

l nhit ti cht hot ng b mt khng ion khng th ha tan, tch ra khi dung dch lm

dung dch tr nn c. i vi cht hot ng b mt khng ion trn c s ethylene oxide, im

c s gim khi di gc alkyl tnghoc khi lng ethylene oxide trong phn t gim xung.

2.6 HLB (HYDROPHILE-LIPOPHILE BALANCE)

Cc tnh cht ca cc cht hot ng b mt lin quan n mi tng quan gia phn i nc

v phn k nc. Nu phn i nc tc dng mnh hn phn k nc th cht hotng b mt

d ha tan trong nc hn, ngc li nu phn k nc tc dng mnh hn phn i nc th cht

hotng b mt d tan trong pha hu c hn. T da vo mitng quan gia phn k nc

v i nc m cht hotng b mt c s dng vo cc mc ch khc nhau. Mi tng quan

gia phn i nc v k nc c c trng bng gi tr HLB (cn phn i nc-i du).

HLB cho bit t l gia tnh i nc so vi tnh k nc, c biu th bng thang o c gi

tr t 1-20. Cc cht hotng b mt ctnh i nc thp s c HLB nh, cc cht hotng b

mt c tnh i du thp s c HLB ln. S gia tng HLB tng ng vi s gia tng ca tnh i

nc.

C th c lng s b gi tr HLB da trn tnh cht ha tan trong nc hay tnh phn tn

ca cht hotng b mt trong nc. ng vi phn tn khc nhau th gi tr HLB khc nhau.

Bng 2.2: c tnh HLB da trn mc phn tn ca cht hot ng b mt trong nc

Mc phan tn HLB

- Khng phn tn trong nc 1-4- Phn tn km 3-6

- Phn tn nh sa sau khi lc 6-8

- Phn tn nh sa bn 8-10

- Phn tn trong m n trong 10-13

- Dung dch trong > 13


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+ Davies chuyn cu trc cht hotng b mt thnh cc nhm thnh phn xc nh

HLB. Gi tr HLB ca cc nhm cho trong bng di y:

Nhm i nc HLB Nhm k nc HLB

- SO4Na 38,7

-COOK 21,1 -CH


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E, P l phn trm khi lng ca EO v ru a chc trong phn t.

+Theo Griffin, nu hn hp c nhiu cht hot ng b mt th

HLBhh = xiHLBi

Vi xil phn khi lng trong tng lng cht hotng b mt

Him c trng hp m i lc ca phn k nc i vi du li bng i lc ca u a nc

i vi nc. C th thy rng t l gia cc lc ny l yu t quan trng quyt nh tnh nng

cht nh ha trong h nh, v vy cn c s nh gi mc cn bng ny.

Trong cht nh ha lm c, nhmalkyl gn lin vi nhm polyoxide ethylene, mi nguyn

t O tng ng vi 3 nhmCH2. Mi nhm (CH2-CH2-O) cn bng vi mi nhmCH2

trong gc alkyl. Sau y l s tham kho tnh cn bng ny ts ngng t sn phm ca ethylene

oxide v stearylalcohol:

CH2H2C

O

H3C (CH2)16CH2OH H3C (CH2)16CH2(OCH2CH2)n OHn + =

(n thay i t 2 n 30 trong nhng sn phm trn th trng)

m mi nhmCH2- hay CH3- nh mt n v th gc k nc l 18 v gc i nc l 3+n

(O l 3 v CH2-CH2O- l n). Nu n15 th xu hng ngcli. Tnh cnbng gia phn k nc v i nc rt quan trng v n quyt nh loi nh tng

hnh thnh. Cng ty ha hc Atlas pht minh mt cch nh lng cho php th hin mc

cn bng ca cht nh ha c nu ln nh mt con s thun HLB. Con s n gin ny l do

s o % ca phn i nc trong phn t chia cho 5. Nu cht nh ha nonionic c 100% i nc

th n s c gi tr HLB l 100/5. Thang o HLB ko di t 0 n 20 (theo l thuyt). Trong

trng hp polyethylene glycol ether ca stearyl alcohol, HLB c tnh nh sau :

Trng lng gc k nc ca stearyl : C18H37= 253Trng lnggc i nc: 44n+17

+Nu n=3, trng lng phn t = 253+[(44.3)+17]=253+149=403

HLB= 149/403*100/5=7.4

+Nu n=20, trng lng phn t =253+897=1150

HLB= 897/1150*100/5=15.6

Kt qu tnh ton gi tr HLB t gi tr nhm c trnh by trong bng sau:


23/66


Bng 2.3: S tng quan HLB gia thc t v tnh ton

Cht hot ng b mt Gi tr thc Gi tr tnh ton

Tween 18 15 15,8

Tween 81 10 10,9

Span 20 8,6 8,5

Span 40 6,7 7,0

Span 60 4,7 5,7

Span 80 4,3 5,0

Glycerol Stearate 3,8 3,7

Span 65 2,1 2,1

2.7 C TNH B MT LNG-RN V QUAN H B MT

TRONG H BA PHA

Cc b mt rn tng t nh cc b mt lng cng cha mt nng lng t do v s

khng cn bng ca lc tc dng ln cc phn t trn lp b mt. Trong iu kinbnh thng,cc cht rn kh t tnh nghng nh cc cht lng, do nng lng b mt cc im

khc nhau s khc nhau khng ging nh cc cht lng. Do vic nghi n cu sc cng b mt

cht rn s kh khn hn. Khng c mt phng php no c th o trc tip c sc cng b

mt ca b mt rn. C th xc nh sc cng b mt ca cc cht rn da vo nh lut

Thomson, biu th mi lin quan gia tan, kch thc ca cc phn t ht nh v cc sc cng

b mt .

Bng 2.4: Sc cng b mt ca mt s cht rn

Cht rn Sc cng b mt (dyn/cm)

CaF2(30oC) 2500

BaSO4(25oC) 1250

PbF2(25oC) 900

CaSO4. 2H2O 270


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Khi mt cht lng tip xc vi b mt rn (khng tan vo cht lng), cc phn t ca c hai

pha s tng tc vi nhau (thng qua lc ht) qua b mt phn chia pha,do lm gim sc cng

b mt. C mt c im khc bit so vi b mt lng lng l y cc phn t ca hai phakhng th chuyn ng qua li b mt phn chia pha. Cng tng t nh b mt lng-lng, b

mt phn chia pha y cng c xu hng gim n mc ti thiu trong nhng iu kin cho

php.

Trong thc t c nhng b mt lin quan n ba pha. V mt hnh hc ba pha ch tip xc vi

nhau theo mt ng giao tuyn. H ba pha thng gp l : L-R-K, L-L-K, L-L-R. H ba pha

gm hai pha rn rt quan trng nhng rt kh nghin cu. Cc h ba pha gm ba cht lng khng

tan lnth rt him gp.

H ba pha thng gp nht l h R-L-K, n gin nht l trng hp mt git cht lng nm

trn b mt rn trong khng kh.

Hnh 2.6: H ba pha ca git cht lng nm trn b mt rn trong khng kh

Trn mt n v chiu di ca chu vi git lng c tc dng ca ba lc, cc lc c xu hng

lm gim b mt phn chia pha nn s c hng nh hnh v.

c gi l gc dnh t

Khi < 90o: cht lng s chy loang ra trn b mt rn gi l hin tng dnh t, lc ny

cc phn t cht lng tc dng vicc phn t cht rn mnh hn tng tc gia chng vi nhau

(RK > RL + LK)Khi > 90ogit cht lng s co li, tng tc gia cc phn t cht lng mnh hn so vi

tng tc gia cc phn t lng v rn, b mt lng rn c xu hng thu v mt im gi l hin

tng trt t.

Hin tng dnh t c s dng gii quyt mt lot cc vn thc t trong cng

nghip nhum, ty git, trong vic s dng thuc tr su hay trong tuyn qung.

(Kh)

(Lng)

(Rn)

LK

RK

LR


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CHNG 3 PHN LOI V NG DNG

CHT HOT NG B MT

3.1 GII THIU CHUNG

Cc cht hot ng b mt c th c phn loi theo cu trc ha hc, theo tnh cht vt l

( tan trong nc hoc dung mi), theo ng dng ha hc.

Phn loi theo cu trc ha hc c th phn theo:

Phn loi theo bn cht nhm ho nc

Phn loi theo bn cht nhm k nc

Phn loi theo bn cht lin kt gia nhm ho nc v k nc

3.1.1 Phn loi theo bn cht nhm ho nc

Theo bn cht nhm ho nc cc cht hot ng b mt c chia thnh cc nhm chnh

nh sau: cc cht hot ng b mt anion, cation,lng tnh v khng ion.

- Anionic

-

- Cationic

+

- Non ionic (NI) (khng phn ly)

- Lng tnh (Amphoteric)

+ -

3.1.2 Phn loi theo bn cht nhm k nc

Gc alkyl mch thng, C8-18

Gc alkyl mch ngn C3-C12 gn vo nhn thm


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Olefin nhnh C8-C20

Hydrocarbon t du m

Hydrocarbon mch di thu c t phn ng CO v H2

3.1.3 Phn loi theo bn cht lin kt nhm k nc v i nc

Gm 2 loi:

Nhm ho nc lin kt trc tip nhm k nc:

RCOONa, ROSO3Na, RC6H4SO3Na

Nhm ho nc lin kt vi nhm k nc thng qua cc lin kt trung gian

Lin kt ester: RCOO-CH2CHOHCH2-OSO3Na

Lin kt amide: R-NHCOCH2SO3Na

Lin kt ether: ROC2H4OSO3Na

3.2 CHT HOT NG B MT ANION

3.2.1 Cht hot ng b mt ngun gc acid carboxylic

3.2.1.1X phng

X phng l tn dng cho cc cht ha hc hay hn hp cc cht to thnh khi acid bo tc

dng vi cht kim. Hay x phng l mui natri, kali ca acid bo (RCOOX).

X phng ch yu thu c t phn ng x phng ha du m ca ng thc vt.

Nguyn tc chnh l thy phn lin kt ester ca glyceride, a v dng acid t do v trung

ha cc acid bo c x phng.

CH2

CH

CH2

OH

OH

OH

CH2

CH

CH2

OCOR1

OCOR2

OCOR3

OH2 R2COOH

R3COOH

R1COOH

3+ +OH-

H+

RCOOH NaOH RCOONa OH2

+ +

C 2 cch to x phng:


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Cch 1: iu ch x phng thng qua acid bo. Cc acid bo c to ra trc, tch ra khi

hn hp glycerin, sau mi trung ha vi NaOH. Vi cch ny, cn thit b phc tp v t

tin. Tuy nhin, li d thu glycerin v iu chnh thnh phn cc acid bo.Cch 2: X phng ha trc tip t du bo. Du c phn ng trc tip vi NaOH, cho ra hn

hp x phng. X phng s c tch bng nc mui. Cch ny li v thit b, chi ph nng

lng nn c dng thng dng hn. Khuyt im l kh tch glycerin.

*Tch lp x phng:

Sau phn ng, dung dch mui n c dng ra, tch glycerin ra khi x phng.

NaRCOORCOONa

X phng khng tan trong nc mui bo ha, do cn bng chuyn sang chiu nghch ->

glycerin li tan trong nc mui -> tch lp -> loi ra.

*Loi mui khi x phng:

X phng th c pha trn vi NaOH long (hay soda), un nh. Mui tan vo dung dch,

sau lm lnh, x phng kt tinh, to lp mn ni ln trn. X phng c tch ra thu. Tinh

ch nhiu ln thu x phng sch.

3.2.1.2

Cc cht hot ng b mt t acid carboxylic thin nhin khca. Acid carboxylic t nha thc vt

Colophane (tng hng) l loi nha thc vt, thu c t nha thng sau khi chng ct hoc

li cun hi nc thu hi tinh du thng. Thnh phn chnh l acid abietic (90%).

CH3

CH3

CH3

CH3

COOH

Colophane c xem nh ph gia hay nguyn liu snxut x phng. X phng colophane

gip tng tan v to bt tt. Chng lm tng kh nng ty ra trong nc cng nn c xem

nh x phng dng vi nc bin.

Nhc im l chng khng bn v c mu. Khc phc bng cch:

+Hydrogen ha: loi b ni i, lm mt mu v loi c tp.


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+Dehydro ha: to vng thm 6 cnh, c kh nng chng oxiha.

+Polymer ha: tng bn, c tnh to nh tt hn.

Colophane tan trong kim, to mui natri gi l x phng colophane.

b. Acid napthenic

Acid napthenic c trong mt s loi du m. Khi x l vi kim, hnh thnh x phng c hot

tnh cao. Acid napthenic th c mu ti, mi kh chu. Nu c tinh ch bng chng ct chn

khng vn cn li mi kh chu . Sn phm thng vn cn 5-10% thnh phn khng x phng

c (ch yu l hydrocarbon).

Cu trc ca napthanic acid l cc acid monocarboxylic khng bo ha, c cha cc vng

cyclopentane, hoc cyclohexane c nhm th alkyl. Thc t, acid napthenic thng c 2, 3, 4

vng, trng lng phn t t 200- 300.

Ph bin l dng dng mui ca kim loi nng ca acid napthenic, v d: mui ng dng cho

nhng si lp nh (v chng nm, khng thm nc). Mui ch dng cho du nht dng p sut

cao.

X phng loi ny tan tt, c hot tnh b mt tt v c tnh st trng. Chng l tc nhn to

bt v to nh tt. Tuy nhin, chng li khng c khuynh hng to gel nh cc acid bo khc.

Chng c dng trong nhng sn phm thng mi, dng ha tan du hydrocarbon.

3.2.1.3Cc cht hot ng b mt t acid carboxylic tng hp

Cc cht hot ng b mt thu c ch yu t phn ng oxi ha parafin rn thnh cc acid

bo tng hp vi mch C thng. Do mch C di, nn khi oxi ha hn hp thu c s rt phc

tp, cha nhiu dng sn phm. Khi oxi ha paraffin C30, sn phm thu c c acid carboxylic

hiu sut 80%, trong 60% l cc phn on C10-20.

- nu x phng: dng phn on C10-20.- sn xut x phng bt: dng phn on C10-16.

- sn xut x phng cc: dng phn on C16-20.

Cc phn on khc cng c dng trong cc lnh vc cht ha do, du bi trn,

3.2.2 Cht hot ng b mt sulfate

Ngi ta dng thut ng cht hot ng b mt sulfate ch nhm cc cht hot ng b

mt c cha nhm sulfateOSO3-trong phn i nc. Nhm sulfate ny c th lin kt trc tip


29/66


vi phn k nc hoc lin kt gintip qua cc lin kt trung gian nh amide, ester, ether

Nhm sulfate c th l nhm phn cc duy nht trong phn i nc hoc l nhm phn cc chnh

trong phn i nc c nhiu nhm phn cc.Alkyl sulfate l cht hot ng b mt tiu biu cho h sulfate ny. Cc tnh cht hot ng

b mt ca alkyl sulfate ph thuc vo cu to v chiu di ca gc alkyl cng nh v tr ca

nhm sulfate trong mch. Cc kt qu thc nghim cho thy:

Kh nng ty ra ca alkyl sulfate bc I tt nht khi mch C cha 12-16 nguyn t,

i vialkyl sulfate bc II tt nht l 15-18. Kh ty ra ca alkyl sulfate bc I tt

hn bc II.

Trong cc alkyl sulfate bc II, tnh hotng b mt gim khi nhm sulfate di chuynvo gia mch. V d nh pentadecyl sulfate: C15H31OSO2ONa bc 2, khi nhm

sulfate di chuyn t C2vo C6th kh nng ty ra ca chng ch cn mt na.

Tnh hotng b mt ca alkyl sulfate gim khi gc alkyl phn nhnh, mt khc s

phn nhnh ca gc alkyl s lm gim kh nng phn hy sinh hc ca alkyl su lfate.

3.2.3 Cht hot ng b mt sulfonate

Ngi ta dng thut ng cht hotng b mt sulfonate ch cc cht hotng b mt c

cha nhm sulfonate (-SO3-) trong phn i nc, nhm sulfonate c th l nhm phn chc duy

nht trong phn i nc hoc l nhm phn chc chnh trong phn i nc cha nhiu nhm phn

cc. Nhm sulfonat c th lin kt trc tip vi phn k nc hoc lin kt gin tip qua cc lin

kt trung gian nh lin kt amide, ester. Qu trnh sulfo ha thu c cc acid sulfonic hay dn

xut ca n c nguyn t lu hunhlin kt trc tip vi nguyn t carbon.

*Cht hot ng b mt alkyl arene sulfonate

Cc cht hotng b mt alkyl arene sulfonate ph bin nht l alkyl benzene sulfonate c

phn k nc l gc alkyl ni vo vng benzene, phn i nc l nhm sulfonate SO3-, gc

alkyl thng c C trn di 12. Chng c mt s tnh cht c bn sau:

Sulfonate cha gc alkyl phn nhnh c kh nng ty ra thp hn so vi

sulfonate c gc alkyl thng.

Gc alkyl cng phn nhnh th alkyl benzene sulfate tng ng cng d tan trong

nc, khi chiu di gc alkyl tng, phn nhnh tng th kh nng ha tan trong nc gim.


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Khi gc alkyl thng, nhm phenyl sulfate v tr C1 kh nng ty ra ca

sulfonate t cc i khi gc alkyl di khongC 11-C 14.

V tr nhm phenyl sulfonate cng nh hng n tnh cht ty ra. Alkyl benzenesulfonate trong gc alkyl l C12, thng, kh nng ty ra tt khi nhm phenyl sulfonate C1,

C2, C3, khi nhm ny di chuyn vo gia th kh nng ty ra gim.

Khi mc phn nhnh ca gc alkyl tng, kh nng phn hy sinh hc gim,

cng mt s lng C, alkyl benzene sulfonate mch thng c kh nng phn hy sinh hc gp

hng chc ln so vi cc alkyl benzene sulfonate nhnh.

Sn phm tiu biu cho loiny c s dng nhiu nht l DBSA (dodecyl benzene sulfonic

acid), trong gc alkyl l tetramer ca propylene:

C

CH3

CH2 C

CH3

CH3

CH3

CH2

C

CH3

CH3

CH3

Hin nay DBSA b cm s dng do kh nng phn hy sinh hc km, c thay bng LAS(Linear Alkylbenzene Sulfonate).

Alkyl benzene sulfonat c nhiu ng dng thc t nh:

+L cht hotng b mt chnh trong cc sn phm ty ra, tiu biu l bt git cc loi.

Hm lng LAS s dng c th trn di 10% cn li l cc cht hotng b mt khng ion,

sulfate natri, phosphate, boran, bentonite LAS c tnh ty ra tt nhng d b kt ta vi ion

Ca, Mg hn alkyl sulfate. Trong trng hp ph gia khng ngi ta thng b sung cht hot

ng b mt khng ion (RO(C2H4O)nSO3Na) tng cng kh nng ty ra.

+ Dng trong snxut nc ra chn. LAS r v nhiu bt, ty ra tt dng km vi LES

(Lauryl Ether Sulfate) tng bt, hotng tt hn trong nc cng. LES t hi da tay. LAS ty

sch du m nhng lm kh da tay cho nn cc sn phm nc ra chn cao cp c thm cc

thnh phnbo v da tay: a) Cht ph gia ngun gc protein (d lm vi sinh vtpht trin), b)

ph gia ngun gc lanolin (kh tan), c) cc cht hotng b mt khng ion, lng tnh

+Trong mt s du gi u cng c s dng LAS (34%) nht l du giu dng cho

tc du v kh nng ty ra ca LAS cao.

+Mt s kem nh rng cng s dng LAS (0,5%).


31/66


+Dng lm cht to bt trong cha chy.

+LAS dng nhiu trong ngnh xi m. Cc b in phn phi cha mt lng cht hot

ng b mt thch hp, thng s dng LAS, alkyl sulfate, . Khi c mt cht hotng b mt,lp m nickel, crom khng b xp, s bng p, bn ha m khng cn qu trnh nh bng ph.

M ng, km, mangan thng dng cht hotng b mt cation. Trc khi m cn phi x l

b mt, ty g st. Cht hotng b mt lm cho qu trnh ty g st d dng, b mt sch, ng

u.

+Trong x l b mt kim loi, LAS, alkyl sulfate, cc cht hotng b mt khng ion

c s dng nhiu. Trc khi sn hay trng men ln b mt kim loi, chng phi x l bng

dung dch H3PO4(phosphate ha b mt chuyn oxide thnh phosphate, kh b n mn). Cc chthotng b mt ny tng cng kh nng thm t, gip cho b mt c x l tt hn v ng

u hn (khng dng x phng).

3.3 CHT HOT NG B MT CATION

3.3.1 Gii thiu

Cht hotng b mt cation khi ha tan vo nc chng s in ly thnh nhng cation c

tnh hotng b mt.

V d: Octadecyl amonium chloride

Cc ion m sinh ra t nhng cht ny khng c tnh hot ng b mt. Cht hotng b mt

cation c gi l x phng o ngc, chng khng c kh nng ty ra cho x si nh cc cht

hotng b mt anion m b hp ph mnh ln x si hoc vi, len. Nhng cng dng quan

trng nht ca cht hotng b mt cation l s dng lm cht st trng, st khun, ty u, dng

trong tuyn ni qung, dng lm cht lm mm nc, cht lm u mu trong cng nghipnhum (vi thuc nhum anion), cht c ch qu trnh n mn, dng trong cc sn phm lm

mm vi. Chng lun c s dng di dng hn hp vi cc cht hotng b mt khc cng

nh vi nhiu ph gia khc.

*Phn loi:

CH3(CH

2)17

NH4Cl

+ -CH

3(CH

2)17

NH4 + Cl

-+


32/66


S hnh thnh ion ca cht hot ng b mt cation ch yu da vo nguyn t N hay S. Tuy

nhin, thng ch cc cht HBM cha N c s dng vo thc t. N thng nm dng amine

hay vng.Nhng cht hotng b mt quan trng l cc amine mch di bc 1, bc2, bc 3, cc mui

amine bc 4 ca chng v mui amoni bc 4. Bi v cc amine rt d chuyn thnh cc mui

amoni bc 4 nn ngi ta xp amine v mui ca chng vo chung mt nhm. Tuy nhin gia hai

loiny c mt im khc bit quan trng v tnh cht vt l, l tan. Cc amine bc 1, bc

2, bc 3 mch di thng khng tan trong nc hay cc dung dch kim m ch tan trong cc

dung dch acid c pH thp proton ha nhm amine. Ngc li cc mui amoni bc 4 c th

tan trong cc dung dch kim, trung tnh hay acid.

Bn cnh cc amine v mui ca chng, cn c mt nhm cc cht hotng b mt cation

cha nit c vng nh vng pyridin:

NC16

H33

+

Cl-

Cetyl pyridium chloride

N N

R

CH3

(CH2)

2NHCOR

+

Cac i mi dazal in bac 4

Ngoi ra cn mt s t cc cht hotng b mt cation khng cha nit m cha lu

hunhnh sn phm thu c khi alkyl ha thio ether, nhng cc cht hotng b mt

cation khng nit t c s dng trong thc t.

Ni chung ngun cung cp nhm k nc cho cht hotng b mt cation cng tng t

nh cho cht hotng b mt anion (acid bo mch di, alcol mch di, paraffin thng mchdi..) nhm k nc c th gn trc tip vo nhm i nc hay qua cc lin kt trung gian

(amide, ester, ether). C mt im khc bit quan trng v c ch hnh thnh ion gia hai loi

ny: cht hot ng b mt anion, nhm hnh thnh ion c hot tnh b mt l carboxylic,

sulfate, sulfonate, cn cht hotng b mt cation: nguyn t N (hoc nhm nguyn t cha

N) l nhm duy nht hnh thnh ion c tnh hotng b mt. Nguyn t N lin kt vi 4 nhm

khc bng 4 lin kt cng ha tr, thng th ch c 1 nhm mch di 3 nhm cn li mch ngn

S

C2H

5

CH3

C16

H33 Br

+

-


33/66


(mt s trng hp c 2 nhm mch di). Cc nhm mch ngn ny cng nh hng nhiu n

tnh cht hotng b mt.

V d: n-octadecyl amine (C18H37NH2) nu thay th nguyn t H ca N bng cc nhm alkylkhc nhau th c th to ra hng lat cc cht hotng b mt c tnh cht khc nhau.

Cng nh cc cht hotng b mt anion, ion khng hotng b mt cng c nh hng

n tnh cht ca cht hotng b mt. cht hotng b mt anion l : Na+, K+, NH4+,

cht hotng b mt cation l halogenua, sulfate, sulfonate, aryl sulfonate (mch ngn). Cc ion

khc nhau s lm cho tnh hotng b mt cng nh tan khc nhau.

3.3.2 Mt s ng dng

*Cht lm mm vi si

Hnh 2.7: S thay i ca si sau khi git

Cc si nh to cc yu im:

-To v th cng

-Ni gi, tng tr cc cht kt ta, ht bn -> lm xm qun o

-Ngn cn dung dch ty ra thm vo -> gim hiu nng git gi

-Thay i phn tn nh sng -> vi m i

V vy, phi s dng cc cht lm mm, du vi. Cht hot ng b mt cation c tnh bi

trn si vi.

Hnh 2.8: Tc ng ca cht lm mm ln b mt vi si


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in hnh l DSDMAC (Distearyl Dimethyl Amoni Chloride) hay DHTDMAC

(Dihydroenated Tallow Dimethyl Amoni Chloride).

Cc in tch dng d b hp ph mnh ln si (in tch m). Ch c dng sau khi git,

khng cho ng thi v s to vi anion thnh cc mui kh tan. (Mt s cng thc c th cho

trc tip nhng thnh phn thay i).

Hiu qu:

-Chng th cng

-Vi vc trn bng, d i

-Hn ch tnh in

Tuy nhin, DSCMAC khng tan trong nc, nu dng qu nhiu s lm qun o b nht, kh

chu v khng thm nc.

Do vn mi trng, DSDMAC v DHTDMAC c thay th bng cc ester amoni th 4

ln d phn hy sinh hc hn, t c hi cho sinh vt sng trong mi trng.

COO CH

COO CH2

N+ CH

3

CH3

CH3

R

RCl

+

COO CH2

R CH2

COO CH2

R CH2

N+

CH3

CH3

CH3SO

4

-

*Trong dung dch dt nhum:

Trong giai on hon tt vi, chng c dng hp ph ln x si, lm gim lc ht

gia cc si. Do vy, vi vc s mm mi hn.

Cng c th thay vai tr ny bng du m c sulfate ha nhng lng cn dng rt nhiu,

khng hiu qu bng vic dng cht hot ng b mt cation.

*Ty trng, dit khun


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Bn thn mt s cht hot ng b mt dng cation c tnh dit khun.

V d: alkyl pyridynium halide, alkyl trimethyl amonium chloride (gc alkyl l C16H33-)

Cc cation ny c dng ty trng qun o, vi vc, tit trng chn bt, ly tch, dngc y khoa,...

3.4 CHT HOT NG B MT LNG TNH

3.4.1 Gii thiu

Cht hot ng b mt lng tnh l cht c cha nhm chc c tnh acid ng thi cha

nhm chc c tnh base. Chng l nhng cation pH thp v l anion pH cao. Trong khong

pH trung gian, chng va tch in m va tch in dng (cu trc lng cc).

Ngi ta chia cht hot ng b mt lng tnh lm 2 loi:

+Cht hot ng b mt lng tnh acid carboxylic

+ Cht hot ng b mt lng tnh sulfate/sulfonate

n gin nht ca cht hot ng b mt lng tnh acid carboxylic l cc amino acid c gc

alkyl di, chng c th c iu ch bng phn ng gia mt amine mch di vi mt acid

carboxylic c halogen ha. Thng dng chloro acetic acid:

HClCOOHRNHCHCOOHClCHRNH 222

Nu cho chloroacetic d, phn ng th i nhn tip tc xy ra to amin bc 3, mui amoni

bc 4.

RNHCH2COOH

ClCH2COOH

ClH

RNCH

2COOH

CH2COOH

N+

CH2COOH

CH2COOH

CH2COO(-)

R

-

ClCH2COOH

ClH -

Cc cht trn l nhng tc nhn thm t v ty git tt trong mi trng acid ln trong

mi trng kim.

iu ch bng cch sulfate ha cc amin mch di c cha lin kt i hay nhm O trong

phn k nc.

V d: sulfate ha oleyl amine


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CH3(CH

2)7-CH=CH-(CH

2)7CH

2NH

2

H2SO4

CH3(CH

2)7CH

2CH CH(CH

2)7-CH

2-NH

2

OSO3H

(1-amino, 9,10-octadecene)

hay

CH3(CH

2)7CH

2CH CH(CH

2)7-CH

2-NH

2

OH

CH3(CH

2)7CH

2CH CH(CH

2)7-CH

2-NH

2

OSO3H

H2SO

4

9- hydroxy octadecyl amine

Cng c th iu ch trc tip t hot ng b mt sulfonic

RNH2 ClCH2CH2SO3H RNHCH2CH2SO3H

R N+

CH2CH

2SO

3H

CH2CH

2SO

3H

CH2CH

2SO

3H

R NHCH2CH2SO3H

CH2CH

2SO

3H

+

c im sn phm:

+Tnh ty ra tt

+To bt

+Khng hi da, khng lm rt da

+t c hi

Do vy, chng thng c dng trong du gi u (c bit cho em b), sa tm,

3.5 CHT HOT NG B MT KHNG ION

3.5.1 Gii thiu

Cc cht hotng b mt khng ion ngy cng c s dng rng ri v chng c th hot

ng tt trong mi trng nc cng, mi trng cha mt lng ln cht in ly cng nh

nhiu ion kimloinng. Ging nh cc cht hotng b mt khc, cc cht hotng b mt

khng ion cng c phn i nc v phn k nc. Khc vi cc cht hotng b mt anion v

cation, phn i nc y c nhng c trng:


37/66


Nh tn gi, phn i nc y khngion ha khi ha tan vo nc nhng vn phn

cc

Phn i nc phi ln th cht hotng b mt tng ng mi c th tan ctrong nc, trong khi phn i nc ca cc cht hotng b mt ion l nhng nhm

chc tng i nh (sulfate, sulfonate, carboxylate.)

Mi tng quan gia phn i nc v phn k nc c th thay i trong mt gii hn

rng (khi chiu di phn k nc khng i) bng cch thay i kch thcphn i

nc.

Phn i nc ni chung ch yu cha lin kt polyether v nhm hydroxyl. Nguyn

liu to phn i nc l ethylene oxide, propylene oxide, polyglycol, diethanolamine, sorbitol

Phn k nc c to thnh t cc hp cht mch di c cha nguyn t H linh ng

nh alkyl phenol, ru, amine, mercaptan, acid bo, amide mch di.

Cc cht hotng b mt khng ion c kh nng ty ra tng i cao, nhng v nguyn tc

km hn so vi cht hotng b mt anion nh sulfate, sulfonate tng ng. Kh nng ty ra

ph thuc vo chiu di nhm k nc v chiu di nhm (-C2H4O-)n. V d i vi iso octyl

phenol c oxyethyl ha, kh nng to bt t cc i khi a vo 15-20 nhm oxyethyl, khi

ko di nhm alkyl hay a thm 1 gc alkyl khc vo nhn thm th kh nng to bt s gim.

Cc cht hotng b mt khng ion khc cng c nhng quy lut tng t. Cc cht hotng

b mt khng ion cng t to bt hn cht hotng b mt ion.

3.5.2 Mt s ng dng

Dng trong du gi u hoc cc loi m phm khc. Cht hot ng b mt khng ion l

thnh phn chnh trong nhiu loi m phm, ty theo tng loi m phm c th m chn la cht

hot ng b mt thch hp.

Du gi u phi p ng yu cu sau:

- C kh nng to bt tt, khi gi u phi cho nhiu bt, bt mn,bn (bt git th bt phi

to)

- D lan rng ln tc v da u

- C hiu qu lm sch tt


38/66


- D r sch sau khi gi

- Tc sau khi gi phi mm mi d chi, khng b ri

- Khng gy kch thch da v mt

p ng cc yu cu trn, phi s dng cht hot ng b mt trong du gi u. Khng

c cht hot ng b mt no p ng ht cc yu cu trn, cho nn phi dng hn hp cc cht

hot ng b mt phi hp vi cc ph gia khc nhau. Cht hot ng b mt khng ion ng vai

tr quan trng. Chng lm gia tng mt s tnh cht cho du gi.

V d nh: lm cho bt bn hn, mn hn, u hn, t hi da hn.Mt s cht hot ng b

mt khng ion nh stearyl ethanolamide c dng lm cht lm c hoc oleyl ethanol amide

c dng lm mt tc. APG (alkyl polyglucoside) thay th cc cht hot ng b mt khc do

c tnh to bt tt, li d phn hy sinh hc, tn dng c ngun nguyn liu t nhin. Tween

l cht hot ng b mt ph bin, l ester ca acid bo v anhydro-sorbitol (sn phm hydrogen

ha ca glucose). Ngoi th trng chng l hn hp ca sn phm, trong c t nht 2 nhm

hydroxyl c ester ha vi acid bo v nhng nhm khc c ester ha vi ethylene oxide.

Ngoi du gi u ra, cht hot ng b mt khng ion c dng trong cc sn phm ty ra

khc nh nc ra chn. Nc ra chn vi t l thp iu chnh bt, n nh bt, tng cng

kh nng hot ng trong nc cng, t hi da.

Trong bt git: cht hot ng b mt khng ion c thm vo tng cng kh nng ty

ra, nht l trong mi trng nc cng v nc cha nhiu cht in ly, gip cho s phn tn

mt lng ln cht hot ng b mt anion (LAS) di dng micelle. Cc cht hot ng b mt

khng ion khng hi da tay nh l cc cht hot ng b mt anion (LAS).

Cht hot ng b mt khng ion cn c s dng lm ph gia trong ch bin thc phm. V

d dng trong b v cc loi du chin. Khi chin bnh, khoai ty, du chin v b thng b bn

ra ngoi do hin tng gia nhit cc b v do nc bc hi qu nhanh. Nu c thm mt lngthch hp cht hot ng b mt vo th nc s thot ra t t v ng u,khc phc c hin

tng trn c th s dng stearyl monoglyceride sulfate hoc ester ca acid bo vi polyol.

Ngoi ra trong ngnh chn nui s dng cht hot ng b mt lm cht kch thch tng

trng, chng gip cho cc cht b d dng hp ph thnh rut, hiu qu s dng thc n c

nng cao, gia sc tng trng nhanh. Mt loi cht hot ng b mt c s dng rng ri VN

l SMG, l monoglyceride sulfate ha (gip tng trng 15-30%).


39/66


Bng 2.5: Lngcht hotng b mt khng ion c sn xut Tu u v USA (ngn tn)

Sn phm Ty u USA

Nm 1990 1996 2000 1990 1996 2000

Alcohol ethoxylate 330

845 875

207 230

560Alkylphenol ethoxylate 90 207 244

Nonionic khc 180 225 225 326 N/A N/A

Tng cng 600 1070 1100 740 740 (E) 890 (E)

Nguyn liu chnh sn xut cht hotngb mt khng ion l ethylene oxide (EO)

Bng 2.6: Lng EO trn th gii (10,5 triu tn/nm) s dng sn xut trong cc lnh vc

Lnh vc sn xut % sn lng

Monoethylene glycol 60%

Polyethylene glycol 10%

Cht hotng b mt 15%

Cc lnh vc khc (glycol ether,

ethanolamine, PET)

15%

D on sn lng tng hng nm: ngn hn l 7% v di hn l 2-3 %

Bng 2.7: Lng ethoxylate c sn xut trn th gii vo nm 1993

Sn phm Khi lng (ngn tn)

Alcohol ethoxylates 750

Alcohol ether sulfates 750

Alkylphenol ethoxylates 600

Ethoxylated nitrogen compounds (khng k

ethanolamides)

50

EO/PO block co-polymers 50

Tng cng 2200


40/66


3.6 NG DNG TNG QUT

Mt s ng dng tiu biu ca cht hot ng b mt

Lnh vc s dng Chc nng

Sn phm chm sc c nhn (Personal care

product)

Ty ra, nh ha, bi trn, chng tnh in (antistatic)

Sn phm ty ra gia nh v cng nghip

(Household & Industrial Laudry &

Cleaning product)

Ty ra, thm t, kim sot bt, nh ha v chng

tnh in

Ho cht nng nghip (Agrochemicals) Nh ha, thm t, performance enhancement

K thut (c kh) Ty ra, nh ha v bi trn

Gia cng si (Fibre Processing) Bi trn v chng tnh in

Ph gia thc phm Nh ha v bn ha (n nh)

Ch bin thc phm Ty ra, thm t, kim sot bt

Du m Nh ha/ph nh, ty, thu hi du trmtch

Sn v latex Nh ha, n nh v phn tn pigment

Polymer Cht tr gia cng/sn xut, cht chng tnh in

Dt Ty git, thm t v u mu, tr phn tn.


41/66


CHNG 4 KH NNG TO NH

TNGNh tng l h c pha phn tn v mi trng phn tn u dng lng. to nh tng

hai cht lng khng tan vo nhau. Trong hai cht lng to thnh nh tng, c mt pha lng

phn cc thng gi l pha nc k hiu n hay w (water)- pha lng kiakhng phn cc thng

gi l du k hiu d hay o (oil).

4.1 PHN LOI NH TNG

Nh tng thng c phn loi theo tnh cht ca pha phn tn v mi trng phn tn

(pha lin tc). Theo cch phn loi ny ngi ta chia nh tng ra lm hai loi:

n/d (w/o : water in oil) gi l nh tng nc trong du gm cc gitnc phn tn trong

du.

d/n (o/w) gi l nh tng du trong nc gm cc git du phn tn trong nc.

Nh tng d/ncn gi l nh tng loi 1 hay nh tng thun. Nh tng n/dcn gi l

nh tng loi 2 hay nh tng nghch.

C th nhn bit v phn bit loi nh tng bng cc phng php sau:

Thm mt t nc vo h nh tng, nc ch trn ln trong nh tng d/n m khng

trn ln trong nh tng n/d.

Thm mt t cht mu ch c kh nng tan vo mt loi cht lng: nc hoc du, n

s nhum mu git cht lng hay mi trng phn tn, qua knh hin vi in t c th

xc nh c nh tng.

o dn in ca nh tng: dn in ca nh tng d/n (# dn in canc) > n/d (rt nh)

Trong mt s trng hp, ngi ta phn loi nh tng theo nng ca pha phn tn, theo

cch ny nh tng c phn lm ba loi: long, c v rt c.

Nh tng long: nng pha phn tn < 0,1 %. Nh tng long khng c ngha l

em pha long nh tng m c c nh tng long m n c nhiu tnh cht

c trng nh: cc ht nh tng long c kch thc rt khc vi cc ht nh tng


42/66


c v rt c, c ng knh khong 10 -5cm, c tch in. in tch ny l do s hp

ph cc ion ca cht in ly v c c mt trong mi trng. Khi khng c cht in

ly th b mt ht nh tng hp ph OH- v H+ do nc phn ly.Nh tng m c: cha mt lng ln pha phn tn, c th n 74 % th tch. ng

knh ht tng i ln > 1m, c th c nhn thy bng knh hin vi thng.

Nh tng rt m c(v d nh nh tng gelatin ha) c t l pha phn tn > 74%

th tch, cc ht khng cn l hnh cu nh 2loi kia m c hnh a din ngn cch

nhau nh t ong, c tnh cht c hc ging nh gel (c th ct bng dao).

4.2 HIN TNG NH HA

S nh ha (emulsification), l qu trnh phn tn mt cht liu vo mt cht liu khc

(thng u dng lng) di dng nhng git cu, hiu qu phn tn s gi c tnh vt l

ny trong thi gian ngn hay di ph thuc vo bn nhit ng m i din y l s

phn lp ca cc pha. Mt s li khuyn c nu ra nhm ngn nga tnh khng bn v

nhit ng ny:

Bng cch tng nht ca pha ngoi, ngi ta c th gim tnh linh ng ca pha

ni nh vic gy ra s kh khn khi chng va chm.

Bo m pha ni tn ti nhng git nh nht v hp l, iu ny s lm gim kh

nng bm dnh ca hai git.

Bng cch tng sc bn c hc ca b mt, s gim lc nhit ng gy ra s kt t.

Lu rng s tng bn m kt qu t s hnh thnh nhng git ca pha phn tn c kch

thc rt nh l mt iu bt thng. iu ny cho thy khi gim kch thc git s lm tng

nhanh din tch b mt v chnh din tch b mt ln c c nh mt nng lng ln c

a vo h. V mt h thng nh th chim gi mt lng d nng lng cao. iuny c vtri ngc vi quy lut v trng thi c nng lng cao s km bn hn trng thi c nng lng

thp. V th, hiu qu n nhv s bm dnh thp ca cc git pha phn tn quan trng hn s

tn ti nng lng b mt t do trong s kt t.


43/66


4.3 CHTNH HA

4.3.1 Khi nim

S cn thit phi c cht nh ha:

Vi nhng lu trn, c th thy rng 2 yu cu cui c lin quan n b mt git ca pha

phn tn. Trc y khi nhng l thuyt v ha l cha c pht trin, nh phng php th

ng v sai ngi ta chng t tnh hp l ca vic lm bn nh bng s to mt hng ro vt

l ti b mt, vic ny khng ch lm mt kh nng lng t m cn c th ngn chn s va chm

gia cc git trong qu trnh hnh thnh nh. l bin php lm gim sc cng b mt. Cht

thch hp c th di chuyn v tn ti trong b mt gia hai pha du v nc, iu ny ch c c

khi cht c mt phn th hin i lc vi nc v phn cn li s th hin i lc vi du (d i

lc khng mnh chm vo cht ).

Nhng cht c kh nng lin kt hai pha trn b mt theo bn cht ca chng c gi l cht

hot ng b mt. Vi c trng ny chng c th lm bn nh. Cht HBM cn c dng

nhiu trong cc ngnh cng nghip khc nh cht lm tan, lm m hay cht thm t. Nhng

chc nng lin quan n vai tr trong s to nh chng minh tnh ph bin ca chng i vi

sn phm v nh.

4.3.2 Phn loi cht nh ha

Theo tnh cht ca phn k nc:

- S a dng trong chiu di gc hydrocarbon.

- bt bo ha ca gc hydrocarbon

- S phn nhnh ca gc hydrocarbon

- S c mt v v tr ca nhm aryl trong gc hydrocarbon

Theo loi in tch

- Anionic

+ Stearate glyceryl SE

+ Glycol stearate v nguyn liu khc

+ Glycol stearate + hexylene glycol + SLES

- Nonionic


44/66


+ Glyceril stearate + laureth_23

+ PED-20 stearate

+ Stearamide MEA stearate

- Cationic

+ Diethylaminoethyl stearate

- Lng tnh

4.3.3 Vai tr ca nh ha trong s hnh thnh nh

-- --- -- -- -- - -- -- -- -- --

-- -- -- -- -- -- -- -- -- -- - - o-- -- -- -- -- -- - -- -- -- -- - --

TSO

TSW s

-- --- --- --- --- --- ---- --- ---

-- -- -- -- -- -- --- -- --- --- -- w

- -- -- -- -- -- -- -- --- -- -- -- -

Cht nh ha trong nh tng tn ti ging nh mt lp phim chthot ng b mt, c th

coi l pha th 3 ca nh tng n nh, hnh thnh 2 sc cng b mt ni, 1 l gia cht hot

ng b mt S vi cht lng ban u l pha nc v 1 l gia S v mi trng bn ngoi pha

nc, tng ng pha du. Hai sc cng b mt mi s c t tn l Twsv Tos. Chng ta thy

rng sc cng b mt ph thuc vo u nh hng ng ca cht hot ng b mt trong mi

trng du hay nc, t l Tws/ Toslin quan trc tip n gi tr HLB. Nu gi tr HLB cao (ln

hn 10) th Tsos di hn Tsw. Lc bn trong mng li tng ng trong trng hp ny c xuhng lm cong b mt pha du, nh vy pha du tr thnh pha phn tn. i vi cht hot ng

b mt c gi tr HLB thp th nc s l pha phn tn. Hin tng trn chng minh tnh hiu

qu ca cht hot ng b mt trong vic hnh thnh nh.

Hin tng trn cho thy cn thit phi c cht nh ho hin din hnh thnh t nht 1

lp n bao ph ln b mt git ca pha phn tn. D dng kim tra iu ny trong phng th

nghim khi ta gim lng cht nh ha cn thit trong 1 h nh tng th sn phm thu c s

khng bn. Ngi ta thy rng khi c s ph v lp phim b mt, sc cng b mt ti im t


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gy xut hin v bo hius d tr cht nh ha trong pha lin tc ti im khuyt tt .

Nhng phn t cht nh ha kha li v sa cha khuyt tt , chng xut hin v trn ln vo

lp phim v c th phc hi khuyt tt trn lp phim 1 cch d dng.4.4 BN VNG CA TP HP NH TNG

Nh tng c khuynh hng to nn cc git ln hn khi kt hp cc git ring bit li vi

nhau, cui cng lm cho h b ph v hon ton v tch ra lm hai lp (hin tng tch pha),

trong mt lp l cht lng ca pha phn tn vi lp kia l cht lng ca mi trng phn tn.

lm bn nh phi dng cht nh ho (emulsifier).

Tnh bn vng ca nh tng ph thuc nhiu vo bn cht v hm lng cht nh ha. Bn

cht ca cht nh ha khng ch xc nh bn vng m cn xc nh c loi nh tng.

Thc nghim cho thy:

+ Nu cht nh ha tan tt trong nc (i nc HLB ln) th s to thnh nh tng d/n

(o/w)

+ Nu cht nh ha tan tt trong du (i du HLB nh) th s to thnh nh tng n/d(w/o).

Nguyn nhn ca iu ny l do cht nh ha ch cn tr khng cho cc ht dnh li vi nhau

khi cc phn t ca cht nh ha phi nm pha ngoi ca ht, tc l cht nh ha phi trong

mi trng phn tn. lm cht nh ha c th dng cc cht c bn cht khc nhau: cc cht

hot ng b mt ion, khng ion, cc polymer, cc cht rn.

Tnh bn vng ca nh tng c quyt nh bi cc yu t sau:

+ S gim sc cng b mt phn chia pha (gii thiu v b mt phn chia pha lng-lng: s

c mt trn lp cht lng th nht, lp cht lng th hai khng trn lnlun dn n s gim sc

cng b mt phn chia pha, s gim ny cng nhiu nu phn cc ca hai cht lng cng gn

nhau, nu phn cc cng gn nhau th hai cht lng s tan lnvo nhau dn n sc cng b

mt tin ti zero, nu hai cht lng ha tan mt phn bng nhau th sc cng b mt lng lng

gn bng hiu s gia hai sc cng b mt ca mi cht lng( bo ha cht kia) so vi khng

kh.

V d: sc cng b mt benzene-nc tnh ton 34,4 v thc nghim 34,4(18 oC).

Chloroform- nc l 33,4 v 33,8 (18 oC).

+ Khi cho thm cht nh ha vo h, chng s hp ph ln b mt phn chia pha, l gim sc

cng b mt, th tch khi cht lng s hng ti dng hnh cu (din tch b mt t cc tiu).


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Khi khi cht lng dng pha phn tn, din tch b mt tng cc htc xu hng kt hp li

din tch b mt gim. Cht hot ng b mt (nhha) l gim sc cng b mt s ngn chn s

kt hp ca cc ht ca pha phn tn.+ Yu t c hc: cht nh ha to thnh mt lp xung quanh pha phn tn, lp ny c

nht cao, c kh nng hydrate ha mnh (d/n) cn tr khng cho cc ht ca pha phn tn kt

dnh li vi nhau.

+ Lp in tch kp:

i vi nh tng d/n, cc ion cht hot ng b mt hp ph ln b mt pha phn tn,

to thnh lp in tch kp, cc ht ny c in tch cng du s y nhau khng cho kt

dnh li vi nhau lm cho h nh tng bn vng.

i vi nh tng n/d: cng c s to thnh lp in tch kpnhng in tch rt nh do

mc in ly km, tuy nhin hng s in mi e nh nn lc y tnh in vn ln

lm bn nh.

+ Th tch pha phn tn chim t l nh lm cho kh nng va chm ca cc ht nh l gim

s kt dnh. Pha lng no c th tch ln hn th d tr thnh mi trng phn tn hn, nhng

iu ny khng phi lun lun ng.

4.5 IU CHV PH V H NH TNG-S O NH

(O PHA)

Trong thc t nh tng c iu ch bng qu trnh phn tn c hc vis c mt ca cht

nh ha. Thng s dng cc thit b khuy trn, gn y ngi ta c n dng sng siu m

iu ch nh tng. Qu trnh nh ha khng ch ph thuc vo bn cht ca cht nh ha v tc

dng c hc, qu trnh nh ha cn ph thuc vo nhit v tng quan v phn cc gia

cc pha.Trong k thut, i khi vn t ra khng phi l iu ch m l ph v nh tng. V d

nh m cao su l nh tng, phi dng phng php keo t ph v nh m tch c cao su

thin nhin cn trong khai thc du m, vic to nh l bt li v phi lm khan loi nc.

Nh tng loi d/n iu ch nh cht nh ha (cht hot ng b mt) anion thng c

ph v bng cch cho keo t di tc dng ca ion kim loi nng (lm kt ta cht nh ha). Nu

cht nh ha l cht hot ng b mt khng ion th cng c th ph v bng cc cht in ly


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nng cao. Lc ny xy ra s mui kt (s tranh ginh cc phn t nc hydrate ha vi phn

phn cc ca cht nh ha).

Tt c nh tng u c th b ph v khi thm cht hot ng b mt thch hp. lnhng cht c kh nng y cht nh ha ra khi lp hp ph nhng khng c kh nng lm bn

nh.

Cc nh tng cn c th b ph v bng ly tm, lc, un nng Khi gia nhit cht nh ha

b gii hp ph ra khi b mt hoc tan vo pha phn tn lm mt tc dng nh ha.

*S o nh:

C th c s thay i qua li gia hai loi nh, gi l s o nh tng. Khi a vo h nh

mt lng tha cht hot ng b mt nh ha cho nh tng ngc li th nh tng ban u b

o li, pha phn tn chuyn thnh pha lin tc. S o nh trong nhng iu kin nht nh c

th c to ra do tc dng c hc lu di. V d nh kem d/n sau mt thi gian di c th

chuyn thnh kem n/d.

4.6 CC BIN PHP LM BN NH

4.6.1 C s v tnh n nh ca nh tng

Khi du c cho vo nc, lc lin kt gia du v nc khng ng k so vi lc lin ktgia cc phn t cng loi, do c s phn lp xy ra nhanh chng. Bng cch lc mnh hay

khuy c th lm hn hp du v nc to nh tng, lc cng mnh th kch thc ht phn tn

cng nh. Tuy nhin, trc sau g th cc ht phn tn cng ln ln thy r v chng s kt t li

thnh 2 lp ban u. Nm c nguyn nhn ca qu trnh nh ha v qu trnh kt t l iu

kin cn thit khi nghin cu hay tm hiu v h nh. C 2 quan im m t hin tng ny c

tnh b sung cho nhau: quan im c hc v quan im nhit ng hc.

a. M hnh c hcKhi hn hp du v nc gm 2 lp b lc to lc xoy. Lc ct ca xoy lc ny s phn ct

cc pha thnh cc khi cu phn tn vo nhau. Lc ct ny b chng li bi sc cng b mt ti

mt tip xc gia ht v khi cht lng. Khi kch thc ht gim xung n cn nhng xoy lc

nh hn. V vy, kch thc sau cng ca git ph thuc gn nh ch vo sc cng b mt ca

mt phn cch v mc xo trn hnh thnh trong pha lin tc.


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Trong khi cc ht ca pha phn tn phn chia th ng thi mt s chng cng kt t li. Qu

trnh kt t c th bao gm 2 giai on :

+ Giai on 1:cc git cng pha phi tin n gn c nhau va chm vo nhau nhngc rt t va chm to kt hp ngay (va chm hot ng). Lp ngn cch gia hai ht va chm c

thlm cho chng bt ra.

+ Giai on 2: khi cc ht tin n gn nhau, gia chng s xut hin lc ht phn t

(Vander Waals) lm chng ht nhau. Do lc ht gia cc phn t trong ni b ht ln hn sc

cng b mt gia hai pha, hai ht trong pha phn tn kt hp nhau. Mc d dng ca qu trnh

kt t tng dn theo kch thc ht.

b.S m t nhit ng

Khi mt cht b phn tn trng thi phn chia nh nht trong cht khc, din tch b mt tip

xc gia 2 pha s ln vt bc. V h ch bn khi mc nng lng n nh (cc tiu) nn cc ht

nh c khuynh hng kt t to thnh ht ln gim sc cng b mt gii phng nng lng

d ra ngoi v a h v dng phn lp ban u.

4.6.2 Cc yu t nh hng bn nh

* nh hng ca s tch in:

- i vi cht nh ha ion (anion hay cation) trong mi trng nc s tch in trn b

mt ca git du, do chnh lc y nhau ca cc in tch cng du trn cc ht gip chng li

qu trnh kt t. T y cho thy rng iu kin n nh l tng khi ton b lp mng phn cch

u c bao bc bi cc in tch.

- i vi cht nh ha khng ion, s tch in cng xut hin khi hai cht lng c hng

s in mi khc nhau b trn ln. Khi cht c hng s in mi cao hn mang in tch

dng v ngc li.

* Lng cht nhha: phi c lng va lng cht to nh ti ra t nht 1 lp ph trn

b mt git phn tn. Thng thng n nh c th c ci thin bi 1 lng cht to nh

vt hn mc cn thit ti thiu.

* S nh hng ca pha: nh hng ca gi tr HLB ca h cht nh ha ng vai tr rt

ln. R rng pha c sc cng b mt ln c khuynh hng to b mt c hnh lng cho, n s

tr thnh pha phn tn. Nu sc cng b mt trn b mt pha bng nhau hoc gn bng th s o

pha xy ra rt d dng. Ngi ta thy rng c 1 gi tr HLB m ti s o pha xy ra rt d.


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* T l du v nc: t l ny c xem nh 1 thng s cm nhn s xut hin nh v

nht, n cn nh hng n bn. Nu pha phn tn chim t l cao (c rt nhiu git) va chm

c hiu qu s tng ln v khong cch trung bnh m cc git n gp nhau c gim xung.Tt c iu ny gia tng kh nng kt t.

* Nhit : khi dng ng cht nh ha th nhit l yu t quan trng c 1 h nh

tng bn ti u. tan ca cht nh ha trong h ph thuc vo nhit , ni cch khc, gi tr

HLB ph thuc vo nhit . V vy, s thay i nhit c th lm gim bn ca nh.

* nht ca mi trng phn tn.

* S phi hp cc cht nh ha.

4.6.3 Cc bin php lm bn nh

* S la chn gi tr HLB ti u.

* m: mt yu t khc lm bn cho loi nh O/W l thm vo cc cht lm m trnh

b kh khi tip xc vi khng kh. S kh ca sn phm m kt qu l s ph v nh tng,

ph thuc vo nhit ca sn phm, mc tip xc vi khng kh v m tng i ca

khng kh. Cht lm m l cc vt liu ht m c tnh cht ht hi nc t khng kh m cho n

khi t cn bng. Cht lm m chc chn khng loi c s kh sn phm. Nng ca cht

lm m trong pha nc ca mt sn phm m phm in hnh thng qu thp khng th cn

bng vi m khng kh. Tt c nhng g cht lm m c th lm c l lm gim mt

nc vo khng kh v hiu qu ny nn tng cng bng vic bao gi kn. Hin nay c 3 cht

lm m c s dng rng ri trong cng nghip m phm l glyceryl, sorbital, propylen glycol.

Ethylene glycol c xem l khng an ton v n b oxi ha bi acid oxalic v bt c s hp ph

no qua da cng c th gy ra si thn. Glyceryl b t vn c kh nng ht m t da.

* Phng thc sn xut: s nh hng nh ph thuc vo cch khuy v tc khuy, vi

tc khuy cho c 1 t l th tch m trn mc ny th pha nng l phn tn cn di mc

ny l pha nh l pha phn tn. Gia gii hn 2 chiu ny (vng cha n nh) cho thy c hin

tng tr. Do vy, nu nc c thm vo nh tng W/O n nh li 1 tc khuy khng i

th cui cng s o pha ti 1 gii hn t l th tch thp hn. Nu thm du vo, khi qua vng

cha n nh, qu trnh nghch o sxy ra nu gii hn trn xut hin. Khi tc khuy tng

im o pha ca mi t l th tch c khuynh hng tng n 1 gi tr khng i ph thuc vo


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cch khuy. Lu rng vi cng th tch pha bng nhau, tc khuy cao, pha nng c khuynh

hng l pha lin tc.

4.7 MT S CHT HOT NG B MT C DNG LMCHT NH HA O/W

HLB Value = 0.5 Chemical description Trade name

8.6 Sorbitan monolaurate Ariacel 20

Armotan ML

Drewmuise SML

Emasol 110

Emsorb 2515

Glycomul

Hodag SML

Span 20

8.8 Polyoxyethylene (5) nonyl

phenol

T-Det N-4

8.8 Polyoxyethylene (5)

monooleate

Ethofat 0/15

8.8 PEG 400 dioleate Emerest 264B

Hodag 42-0

Pegosperse 400 DO

Tegester PEG

400 DO

9.0 Polyoxyethylene (5)

monostearate

Ethofat 60/15

9.0 Polyoxyethylene poiyol fatty

acid ester

Arlatone T


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9.1 Polyoxyethylene (5) oleyl

ether

Arosufl JL-457

9.6 Polyoxyethylene (4) sorbitan

monostearate

Glycosperse S-4

Tween 61

9.6 PEG 400 dilaurate Emerest 2652

Hodag 42-L

Kesso 182D46

Pegosperse 400 DL

9.7 Polyoxyethylene (4) lauryl

ether

Brij 30

Ethosperse LA-4

Glycosperse LA-4


monooleate

Emsorb 6901

Glycosperse 0-5

Sorbinox 0-5

Tween 81

10.0 Polyoxyethylene (5) laurate Arosufl MFL-418

Ethofat C/15

10.4 PEG 300 monooleate Neutronyx 834

10.4 PEG 600 dioleate Hodag 62-0

10.5 PEG 600 distearate Hodag 62-S

S 1013


tristearate

Armotan PTS-20

Emorb 6907

Glycosperse TS-20

Hodag PSTS-20

Sorbinox TS-20


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Tween 65

10.8 Polyoxyethylene fatty

glyceride

Arlatone G


trioleate

Emsorb 6903

Hodag PSTO-20

Sorbinox TO-20

Tween 85

11.0 Glycerol monostearate, sefl-

emulsifying

Arlacel 165

11.0 Polyoxyethylene lanolin

derivative

G-1790


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CHNG 5 CHT HOT NG B MT

V CC H BT

5.1 BN VNG CA TP HP BT

Bt in hnh l h phn tn m cc cht th v rt c ca pha kh (thng l khng kh)

trong cht lng. Kch thc bt kh c mm v trong mt s trng hp c th ln n cm. Do c

tha pha kh v cc bt kh ny p ln nhau nn cc bng kh s mt dng hnh cu v tr thnh

hnh a dinphn cch nhau bi mng rt mng ca mi trng phn tn. Cn phn bit vi bt

l cc h K/L nng thp trong cc bt kh nm xa nhau.

Cc h bt c to ra bng cch phn tn kh trong lng khi c mt cht to bt (foam

booster). Cht lng khng c cht to bt th khng th cho bt bn vng. bn vng ca bt

cng nh thi gian tn ti ca bt ph thuc vo tnh cht ca mng bao quanh, c quyt nh

bi bn cht ca cht to bt cng nh hm lng s dng, thng s dng cc cht hot ng b

mt tng hp hoc cc cht hot ng b mt thin nhin nh saponin, cc protein

S tn ti tng i ngn ca bt v s ph v bt kh do s chy ca mng cht lng di

tc dng ca trng lc. Vai tr cacht to bt l lm chm li s chy ca cht lng (cu to ca

mng bt nh sau)

Hnh 2.9: Cu to mng bt


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bn vng cc i ca bt ng vi cht hot ng b mt c gc hydrocarbon trung b nh v

vi dung dch c nng trung bnh. Nhng cht thp hn trong dy ng ng c tnh hot

ng b mt km, nhng cht cao hn c ha tan thp.Bn cnh bn cht v nng ca cht to bt, thi gian tn ti ca bt cn ph thuc vo

nhit , nht ca dung dch..Tc ph vbt thng tng theo nhit do s gii hp

ph cht to bt trn b mt phn chia pha v do s bong trng cht lng, lm cho mng b

mng i dn n ph v. S tng nht ca dung dch lm tng bn cho bt.

5.2 CC NGUYN NHN LM BN BT

Cc nguyn nhn lm bn bt cho n nay cng cha c lm sng t, nhiu nh nghin

cu kt lun rng khng c mt thuyt duy nht gii thch cho s bn vng ca bt, nguyn nhn

tn ti ca bt iu ch t cc cht to bt khc nhau, trong cc iu kin khc nhau c th rt

khc nhau. Cc nguyn nhn chnh lm bn bt nh: do lc tnh in, do s hydrate ha, do

nht, do tnh n hi ca mng..

Lc tnh in: do lc y tnh in gia hai u phn cc cahai lp anionic hp ph trn

ranh gii lng kh, lm cho mng ngn cch bt kh khng b mng i. Khi c mt cht

in ly vi lng ln, dy ny gim do lp in tch kp gim n mt lc no ,

mng bn do s hydrate ha cht to bt ch khng cn do lc y tnh in na.

nht: mt s nh nghin cu cho rng cc mng bn vng do c nht cao khi c

cht to bt hp ph ln mng, tuy nhin nhiu nh nghin cu khc cho thy c th to ra

cc mng bn m khng cn c nht cao.

Tnh n hi ca mng: nhiu nh nghin cu cho rng cc mng ny bn l do c tnh

n hi. Tuy nhin, theo s gim b dy ca mng, tnh n hi tng. iu ny cha gii

thch c ti sao tnh codn tng, mng b v.

5.3 CC TC NHN LM TNG BT (FOAM BOOTSTER)

Khi lp cng thc c th thay i c tnh to bt ca sn phm ty theo yu cu ca ngi

tiu dng. C th thc hin:

Chn cht hot ng b mt to bt hay khng to bt

S dng cc ph gia lm tng bt.


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5.3.1 Chn la cht hot ng b mt

Mt cht hot ng b mt hay hn hp cht hot ng b mt c th lm thnh h thng to

bt. Thng thng, s lng bt tng vi nng t ti a quanh CMC. Nh vy v mt l

thuyt c th tin on khnng to bt ca mt cht hot ng b mt da trn CMC ca n.

Tuy nhin iu ny khng c lin quan n tnh cht n nh ca bt.

Cc yu t nh hng n CMC c th tng hoc gim bt l:

Nhit :Khi nhit tng, ha tan ca cht hot ng b mt anionic tng lm

kh nng to bt tng.Ngc li i vi NI, ha tan (do kh nng to bt) gim

vi nhit sau im c.

S c mt ca cht in ly: lm gim tr s CMC ca cht hot ng b mt lm

thay i kh nng to bt ca cht hot ngb mt

Cu trc phn t ca cht hot ng b mt:Theo l thuyt kh nng to bt ty

theo cu trc phn t ca cht hot ng b mt .

Tuy nhin trn thc t rt phc tp v khng c s tng quan trc tip gia kh nng

to bt v s n nh bt. Tuy nhin c nhng nguyn tc tng qut nh sau:

+ Cht hot ng b mt NI t to bt hn cht hot ng b mt ion trong dungdch nc.

+ i vi cng mt h cht hot ng b mt, CMC cng km th kh nng to bt

cng cao. V d nh i vi alkyl sulfate, khi chiu di mch C tng kh nng to bt tng.

+ Cation i ca cht hot ng b mt anion c lin quan n s n nh ( bn)

ca bt. Theo Kondon v Co s n nh bt ca dodecyl sulfate gim theo th t sau:

NH4+> (CH3)4N

+> (C2H5)4N+> (C4H9)4N

+

5.3.2 S dng cc cht ph gia lm tng bt

Theo Schick v Fowker, vic thm vo mt s hp cht i cc (ion i) c th lm gim

CMC ca cht hot ng b mt. Khi hp cht c cng mch C vi cht hot ng b mt th kh

nng to bt v n nh bt tng:

Ether glycerol < Ether sulfonyl < Amide < Amide thay th

Trong thc t ngi ta s dng mono hay diethanol amide lm nhng cht tng bt trong

bt git to bt, nc ra chn hoc du gi u.


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5.4 CC TC NHN CHNG BT (ANTIFOAMER)

Cc cht chng bt tc ng theo hai cch:

- Ngn cn s to bt: thng l cc ion v c nh canxi c nh hng n s n nh

tnh in hoc gim nng anion bng kt ta

- Hoc tng tc phn hy bt: l cc cht v c hay hu c s n thay th cc phn

t cc cht hot ng b mt ca mng bt lm mng bt t n nh (khng bn).

Khi thm cht hot ng b mt NI vo cht hot ng b mt anion lm gim bt ng k.

Tuy nhin h thng anionic/ NI ny vn cn qu nhiu bt.

5.4.1 C ch ph vbt bng cc ht k nc

Xt m hnh sau:

Cc ht k nc c th c to thnh khi cho x phng vo cng thc bt git. X phng s

tc dng vi ion canxi to thnh x phng canxi (k nc) khng tan. Cc ht ny s nm trn

mng bt v tr nn khng ng nht.Phn mng tip xc vi ht k nc tr nn mng dn v

sau cng t to l v bt b ph v.

H thng anionic/NI/x phng c s dng trong thi gian di sn xut cc sn phm

khng bt dng cho cc my git. X phng no c hiu qu ph bt caov c sp xp theo dy

sau:

X phng m c voi > x phng colza > stearate > x phng m b > x phng du da.

Tuy nhin h thng ny c cc nhc im sau:

+ Thiu hiu qu nc ngt (khng c s to thnh x phng canxi)

+ ng bnh (gel ha) trong b phn phn phi bt (khi nhit thp)

Lng(L)

Khng kh(K)

Phim

(K)

Ht knc

Lng(L)

Khng kh(K)

(K)

Ht knc

Phim


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5.4.2 C ch chy loang (spreading)

Xt m hnh sau:

H thnganionic/NI vi cc tc nhn chng bt c s dng rng ri bao gm:

+ Stearyl phosphate (mono v distearyl phosphate)

+ Du v sp

+ Cc silicon,silic k nc

Cc hp cht ny tc dng theo c ch chy loang. Cc phn t ca chng di chuyn v pha

b mt ca mng bt thay th cc phn t ca cht hotng b mt. Nh vy mt b mt c

bt c thay th bi b mt t bt hn.iu ny ch c th thc hin c bi mt hp cht c

sc cng b mt km c kh nng chy loang trn b mt dung dch. c tnh ny c biu din

bi h s chy loang S:

S = F (A- FA)

Vi: * F: sc cng b mt ca dung dch to bt

* A: sc cng b mt ca tc nhn chng bt

* FA: sc cng b mt ca dung dch to bt/chng bt

5.5 IU CH V PH V BT

Bt c iu ch bng cch sc kh cn thit (thng l khng kh) i qua dung dch cht

to bt bng cch khuy mnh cht to bt. Trong nhiu trng hp s to bt c ngha

thc t to ln:

+ Bt c vai tr trong qu trnh tuyn ni qung

+ S to bt l yu t tch cc trong qu trnh git gi

Lng(L)

Khng kh(K)

Phim

(K)

Silicon/Du

Lng(L)

Khng kh(K)

(K)

Silicon/Du

Phim


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+ Nh s to bt v sau khbt, c th lm sch mt s cht lng khi cht hot ng b

mt

+ Bt c ngha to ln trong cu ho, dp tt m chy ngi ta d ng bt trong phaphn tn l carbon dioxide, ngn khng cho khng kh tip xc vi m chy

+ S to bt l cn thit khi sn xut cc cht do xp

Trong mt s trng hp s to bt l khng cn thit, cn loi tr. V d nh khuy trn

mt s dung dch bt d hnh thnh, gy kh khn cho qu trnh khuy trn. . Vic ph bt

bng cch thm vo cht chng bt (antifoamer) nh cc dn xut ca silicon, mt s ru.

C th ph bt bng cch gia nhit. Khi nhit tng xy ra s gii hp cht to bt, nhit

lm bc hi dung mi, lm cho bt b ph v. C th ph bt bng bin php c hc hay htchn khng.


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CHNG 6 KH NNG TY RA

6.1 C CH TY RATy rani chung (detergency) l mt qu trnh lm sch (cleaning). Cht ty ra ni chung

(detergent) l bt c tc nhn no c kh nng lm sch. Tuy nhin khi nim ty ra y ch

qu trnh lm sch b mt rn (bao gm c vi si) trong mt dung dch trong c cc qu trnh

ho l xy ra. Nu b mt rn b dnh cc cht bn tan c trong nc (nh ng) th chuyn

cc ht bn vo dung dch khng c kh khn g, ch cn tc dng ca cc lcc hc nh ch

xt.hoc ty ra cc vt bn du mbng dung mi hu c. Vic ty ra ny khng xt y.

S ty ra bao gm:

Ly i cc vt bn khi cc b mt rn (vt dng, vi vc)

Gi cc vt bn ly i ang l lng trn

giao trinh_chat hoat dong be mat

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