formaldehyde use and alternative biobased binders for...

Review ArticleFormaldehyde Use and Alternative Biobased Binders forParticleboard Formulation A Review

Stephen Warui Kariuki Jackson Wachira Millien Kawira and Genson Murithi

Department of Physical Sciences University of Embu PO Box 6-60100 Embu Kenya

Correspondence should be addressed to Stephen Warui Kariuki stephowaruiyahoocom

Received 30 June 2019 Revised 1 September 2019 Accepted 19 September 2019 Published 13 October 2019

Guest Editor Zhichao Jin

Copyright copy 2019 StephenWarui Kariuki et alis is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Formaldehyde-based resins are conventionally used as a binder in formulation of particleboard Epidemiologic studieshave shown that formaldehyde is carcinogenic Efforts to reduce the health hazard effects of the fomaldehyde-based resin inthe particleboard formulation have included use of scavengers for formaldehydes and use of an alternative binder Use ofscavengers for the formaldehyde increases the cost and maintenance of particleboard formulation ere is no proof thatscavengers eliminate the emission of formaldehyde from particleboard Use of biobased binders in particleboard for-mulation provides an alternative for eliminating use of the formaldehyde-based resin However the alternative is hinderedby challenges which include limitations of physical and mechanical properties e challenge has continuously been actedupon through research e paper presents an overview of the use of starch as an alternative binder Improvement overtime of the starch and limitations thereof requires to be addressed Use of the modified starch has shown increasedparticleboard performance Mechanical strength such as modulus of rupture modulus of elasticity and internal bondingin particleboards however remains to be a challenge

1 Introduction

11 Formaldehyde-Based Resins and ParticleboardFormulation Formaldehyde is used in industries for thesynthesis of resins and adhesives used during formulation ofparticleboard [1] Phenol formaldehyde (PF) resins are usedas adhesive for fixing together panels of exterior-gradeplywood the flakes of oriented strandboard panels andparticleboard [2] Phenol formaldehyde resins provide highstandards of physical and mechanical properties whichinvolve high strength and resistant to moisture is pre-vents delamination and gives excellent temperature stabilityis is due to the more flexible nature of phenolic resins [3]However high cost of PF is due to fluctuations in cost ofphenols and undergoes hydrolysis to emit formaldehydesInvestigation aimed at use of cheaper and formaldehyde-freeproducts as substitute of phenol-formaldehyde based on notonly environmental but also economic grounds Lignin hascomparatively low price and high phenolic moieties along

with environmental considerations render it as a suitablesubstitute for phenols in the manufacture of PF [4 5]

Urea formaldehyde (UF) resin is widely used as adhesives inthe particleboard industryUF is cheaper compared to PFereare two major limitations of wood composite boards based onUF binders first high emission of formaldehyde during bothproduction and second subsequent exploitaion of the boards[6] Particleboard formulated with urea formaldehyde shownpronounced thickness swelling to water and hence they areunsuitable for outdoor use [7] Measures used to reduceformaldehyde emissions involve decrease of the formaldehydeurea molar ratio [8] Unfortunately the decrease in formal-dehydeurea ratio has resulted in deterioration of physical andmechanical properties of particleboard at the same time

12 Formaldehyde Emission and Formaldehyde Scavangerse other method used to reduce formaldehyde emission isby use of chemical additives called formaldehyde scavangers

HindawiJournal of ChemistryVolume 2019 Article ID 5256897 12 pageshttpsdoiorg10115520195256897

e most commonly used scavangers are compoundscontaining amine such as urea ammonia melamine anddicyandiamide [9] Melamine reacts with formaldehyde toform methylolamine as shown in equation (1) [10]

C3H6N6 + CH2O⟶ C4H8N6O (1)

Dicyandiamide reacts with two moles of formaldehydeas illustrated in equation (2) to form methyloldicyanamides[11]

C2H4N4 + 2CH2O⟶ C4H6N4O (2)

Urea reacts with formaldehyde to form mono-methylolurea as shown in equation (3) [12 13] Ureaformaldehyde resin is used in formulation of particleboardas a binder other than a scavanger

CO NH2( 11138572 + CH2O⟶ C2H6N2O2 (3)

Sodium metabisulphite (Na2S2O5) is a scavenger used inparticleboards produced with urea formaldehyde and mel-amine formaldehyde resins Sodium metabisulphite reactswith water to form sodium hydrogen sulfite as shown inequation (4)

Na2S2O5 + H2O⟶ 2NaHSO3 (4)

Sodium metabisulphite reacts with formaldehyde as ascavenger to form a bisulfite adduct [14] as shown inequation (5)

HCHO + NaHSO3⟶ HOCH2SO3Na (5)

Sodium hydrogen sulfite also reacts with sodium hy-droxide to form sodium sulfite as shown in equation (6)

NaHSO3 + NaOH⟶ H2O + Na2SO3 (6)

Sodium sulfite scavenger formaldehyde in the presenceof water to form bisulfite adduct as in equation (7) [14]

HCHO + Na2SO3 + H2O⟶ NaOH + NaSO3CH2OH(7)

Ammonia is a good scavenger for the emitted formal-dehyde [15] Green tea catechin as a formaldehyde scavengerreduced formaldehyde from plywood manufactured withformaldehyde-based resin Green tea extract reducedformaldehyde emissions from plywood [16] Proanthocya-nidic was found to protect kidney tissue against formalde-hyde [17] Tannin was mixed with low molecular phenol-formaldehyde resin in manufacture of plywood It was usedto scavenge against emitted formaldehyde [18]

Prolonged human exposure of formaldehyde lead tochronic toxicity and cancer [12 19] Formaldehyde can causenasopharyngeal cancer [20] Lu et al [21] reported on gen-otoxic and cytotoxic modes of action for the carcinogenesis ofinhaled formaldehyde in respiratory nasal epithelium [21] Anincreased incidence of myeloid leukemia has been reported

Increased exposure of formaldehyde to workers in a fu-neral homes resulted in mortality from myeloid leukemia [22]and lymphohematopoietic malignancies [23ndash25] e mostconsistent pattern was death as a result of myeloid leukemis

[26] A study of 11039 textile workers produced a certainrelationship between the duration of formaldehyde exposureand leukemia-related deaths [27] e exposure assessmentbased on 594 workers produced the mean exposure levelsbetween 009 and 020 ppm and the levels were relativelyconstant with no peaks or intermittent exposures Leukemiahad the highest standardized mortality ratio (SMR) withmajority of occurrences from garment factory e epide-miological literature on formaldehyde and leukemia is ex-tensive Many studies have shown a correlation betweenformaldehyde and cancer-related complications [26]

13 Use of Starch and Starch Derivatives as Substitutes forParticleboard Formulation Adhesive technology is movingtowards replacements of formaldehyde-based adhesives touse of biobased resources [28ndash30] Various types of starchmodification on its crystalline nature include chemicaltreatments such as oxidation using hypochlorite [31] and air[32] esterification [33] and cationization [34 35] Physicalmodification of starch includes mechanical activation [36]microwave [37 38] ultrasonic degradation [39 40] heat-moisture treatment [41] and enzymatic treatment [42ndash44]e modified starch has been utilized in particleboardformulation [45ndash48]

Selamat et al [46] compared physical and mechanicalproperties of particleboard formulated from rubberwoodwith urea formaldehydes and native starch separately asbinderse native starch was extracted from oil palm trunkParticleboard bonded with formaldehyde showed thicknessswelling of 1117 and water absorption of 8208 whencompared to the native starch with thickness swelling of8208 and water absorption of 17452 [46] is showsthat formaldehyde-based resin is more than twice better thanthe carboxymethyl starch although the main drawback isemission of formaldehyde Formaldehyde has been found tohave carcinogenic properties [21 49ndash51] High water ab-sorption of particleboard formulated with the carbox-ymethyl starch may be attributed to the presence of hydroxylgroups Hydroxyl groups form hydrogen bonding withwater is increases water absorption and thicknessswelling thus affecting mechanical properties of the parti-cleboards Methylene diphenyl diisocyanate (MDI) weresmall and had better mechanical and chemical bondingability [52] Improvement in chemical bonding results inimprovement in mechanical properties of the particleboardformulated

Natural starch is in the disorganized metastable state andas such is easily dispersed in warm water [53] Carbox-ymethylation therefore is a chemical modification methodthat is vital and versatile for transforming starch Trans-formation of starch involves provision of water solublepolymers and intermediate of valuable functional attributes[54] Carboxymethylation of starch (CMS) involves partialsubstitution of hydroxyl group (-OH) with ether group (-O-CH2COOH) Starch reacts with monochloroacetic acid toproduce carboxymethyl in the presence of sodium hydroxidein three different steps Step one involves reaction of starchwith starch as shown in equation (8)

2 Journal of Chemistry

ROH + NaOH⟶ RONa + H2O (8)

Step two involves the reaction between sodium saltformed with monochloroacetic acid to form sodium mon-ochloroacetate (SMCA) as shown in equation (9)

RONa + ClCH2COONa⟶ ROCH2COONa + NaCl(9)

Alternatively SMCA reacts with sodium hydroxide toform sodium glycolate

NaOH + ClCH2COONa⟶ HOCH2COONa + NaCl(10)

Carboxylmethylation therefore improves the rheologicalproperty of the native starch that improves particleboardcharacteristics [54]

Starch inwater undergoes limited reversible swelling but theintegrity of the crystal structure is such that it does not dissolve[55] Starch gelatinization at low temperatures can be induced byaddition of aqueous alkali [56] Sodium hydroxide reacts withhydroxyl groups of starch thus improving the thickness swellingand water absorption of the native starch by 8 and 22respectively is is attributed to reduction of hydroxyl groupsthat were reacted with sodium hydroxide Another reason couldbe as a result of reaction between carboxylic group in mono-chloroacetic acid and hydroxyl groups in starch through es-terification process Particleboard bound with ureaformaldehyde had the highestmodulus of rupture (MOR) valuesfor medium density of 963Nmm2 while those bound by thenative starch gave the lowest of 338Nmm2 Same trend wasfound in modulus of elasticity and internal bonding with336912Nmm2 206895Nmm2 and 198Nmm2 096Nmm2respectively [46] Improvedmechanical strength from the nativestarch to carboxymethyl starch is attributed to the cross-linkingof the composite material with highly branched carboxymethylleading to formation of stronger covalent bonds than hydrogenbonding found in the native starch Carboxymethyl starchtreatment improved the MOR thus attaining the minimumJapanese Industrial Standard [46] MOR is still very low com-pared to particleboard formulated from urea formaldehydeere is no interaction between the functional groups of thelignocellulose material and the starch which leaves a majordeficit in reinforcement of the bond between the components ofthe particleboard is presents a challenge that requires con-sideration Treatment with sodium hydroxide and temperaturereduces the sizes of starch making them disperse more withinthe lignocellulose matrix

Despite the growing interest in bioplastics the use ofstarch-based plastic is still limited due to its brittleness andmoisture sensitivity Addition of polyvinyl alcohol (PVA)reduces the brittleness of the bioplastic [57] and latex in-creases water resistance [58] Shi and Tang [47] usedpolyvinyl alcohol solution with styrene-butadiene (SBR)latex and polymeric methyl diphenyl diioscyanate to modifycorn starch Particleboard formulated showed MOR rangefrom 1326Nmm2 to 1654Nmm2 MOE range from1508Nmm2 to 1768Nmm2 and IB range from 017Nmm2 to 032Nmm2 [47] Starch-based adhesives gave the

particleboard better prepressing property and sizing uni-formity Pan et al [59] used polymeric methylene diphenyldiisocyanate to modify rice bran for making an adhesive formaking particleboard Average MOE for particleboardformulated was 2545Nmm2 MOR 21Nmm2 and IB of035Nmm2 [59] e study showed that the rice bran ad-hesive produced can be used to replace a portion of thesynthetic adhesive pMDI currently used for the fabricationof rice straw particleboard Addition of PVA latex and SBRwill improve moisture resistance water absorption andthickness swelling which in turn reduces mechanicalproperties

Xu et al [60] used butyl acrylate (BA) as a comonomer insynthesizing the corn starch-based wood adhesive ebonding performance was close to that of commercialpolivinyl alcohol solutionis cassava-based wood adhesive(SWA) improved in stability more than the corn starch-based wood adhesive Improved stability was attributed byits low minimum film forming temperature (MFFT) andglass transition temperature (Tg) of the cassava starch [60]Zhu and Zhuo [61] used butyl acryrate to modify the cornstarch used for encapsulating carborxylic-containing com-pounds through graft copolymerization e encapsulatedorganic materials showed low swellability large encapsu-lating capacity and low solubility in water [61] Lowswellability property is crucial in formulation of particle-boards Liu and Su [62] used butyl acrylate to modify potatostarch through grafting via surface-initiated atom transferradical polymerization [62] Graft modification provides asignificant route to alter physical and mechanical propertiesof biobased adhesives [63]

Starch contains many hydroxyl groups which make itextremely polar leading to low interaction with nonpolarmaterials [64] Starch-based adhesives wet the polar surfacesof cellulose penetrate crevices and pores and thus formstrong bonds Imam et al [65] cross-linked corn starch withpolyvinyl alcohol (PVOH) using hexamethoxy methyl-melamine (HMMM) to bond lignocellulose materials to-gether in an acidic medium Under this condition methoxygroups from HMMM reacted with the hydroxyl group fromstarch in the presence of PVOH to form ether bond [65] asin Scheme 1

Ether bonds are covalent bonds which are stronger thanhydrogen bonding in starch e binder in formulatedparticleboard remained intact showing superior bondstrength establishment e boards fractured during me-chanical testing is is attributed to use of an acid mediaduring particleboard formulation e use of an acid medialimits activation of functional groups in lignocellulosematerials Particleboard made from rice straw and thepolyvinyl starch-based adhesive gave the following resultsMOR IB and TS of up to 31Nmm2 049Nmm2 and 20respectively [65] Use of urea formaldehyde-based resin as abinder gave MOE IB and TS of up to 2219Nmm2 05Nmm2 and 75 [66] Researchers worked with differentparticle sizes and found that the starch-based adhesive gavecomparatively better physical and mechanical propertiesProperties of polyvinyl alcohol-based resin were greatlyinfluenced by the interaction between the adhesive and

Journal of Chemistry 3

lignocellulose material ese properties are still below ex-pectations and can be boosted by use of an alkali whichactivates functional groups in lignocellulose materials [67]

Akinyemi et al [68] used glutaraldehyde to degrade thecassava starch in the presence of acidic medium Hydroxylgroups in starch molecules were replaced by glutaraldehydeas indicated in Scheme 2

e modied starch was used to bind wood chips informulation of sawdust particleboard Particleboard for-mulated using this modied starch gave the following re-sults MOE and MOR of 3232Nmm2 and 357Nmm2respectively Comparatively melamine-formaldehyde (MF)was also used by Cui et al [69] to obtain MOE and MOR of2701Nmm2 and 1421Nmm2 respectively [68] MF un-dergoes hydrolysis leading to produce formaldehyde Starchmodied with glutaraldehyde gave better mechanicalstrength than their formaldehyde counterpart Glutaralde-hyde is harmful and this has necessitated the use of sodiumbisulfate as a scavenger to neutralize its eect [70]

2Na+HSO3ndash + OHCndash(CH2)3ndashCHO 2Na+ C

OH

SO3ndash

(CH2)3ndashC

OH

SO3ndash

(11)

Starch reacts with polyurethane polymer via terminalhydroxyl group in starch through grafting [71] as shown inScheme 3

Polar hydroxyl groups are replaced with the hydro-phobic aromatic urethane functional group [72] Poly-urethane has been used to modify castor oil starch used informulation of particleboard made from sugarcane bagassee board had WA TS MOE MOR and IB of up to 20120 226Nmm2 2850Nmm2 and 118Nmm2 re-spectively [73] Urea formaldehyde and melamine formal-dehyde resin binders for sugarcane bagasse produced WATS MOR MOE and IB of 6487 and 3252 2471 and1266 7578Nmm2 and 105328Nmm2 366Nmm2 and553Nmm2 and 02Nmm2 and 045Nmm2 respectively[74] Formaldehyde-based resin produces formaldehydewhich is a carcinogen Although modied starch resinproduced higher physical and mechanical properties com-pared to its formaldehyde-based resin its properties are stillvery low Mechanical properties of particleboard made usingstarch-based adhesive modied polyurethane improved bycrosslinking with lignocellulose material

Starches modied with octenyl succinic anhydride(OSA) have been used in a range of industrial applicationsparticularly as a food additive OSA is hydrophobic and alsohas steric eects Starch reacts with OSA to form starchoctenyl succinate as shown in Scheme 4

N

N N

NN

N

CH2

CH2

CH2

CH2

CH2 CH2

H3CO

H3CO

OCH3

OCH3

OCH3 OCH3

HO Wood

HO Starch

HO PVOH

NN

NN

N

N

CH2CH2

CH2CH2

CH2

CH2

O O

O O

O

O

Starch HOVP

Wood

Starch

WoodPVOH

H3C OH+

Catalyst

Scheme 1 Schematic chemical crosslinking reaction [65]

OHO

OH

H

O

H

H

HH

OHC

OHC

OO

O

H

O

H

H

HH

CHO

OH

OHC

OH

n

+

+

n

Starch Glutaraldehyde

H

Scheme 2 Modied starch by glutaraldehyde


Sweedman et al [75] modified indica rice maize waxymaize and potato with octenyl succinic anhydride (OSA)between the temperatures of 30 to 40degC Due to hydrophobicand steric contributions of OSA and highly branchedmacromolecular starch structure modified starch displayuseful stabilizing encapsulating interfacial thermal nu-tritional and rheological properties [75] Altuna et al [76]modified starch with octenyl succinic anhydride to yield ahydrocolloid with amphiphilic properties the octenyl suc-cinylated starch e octenyl succinylated starch finds wideapplication in the food industry mainly as emulsifier en-capsulating agent and fat replacer [76] Research in-vestigating the reaction between OSA and modified waxymaize starch showed that OSA reacts with maltodextrine

better than the native starch is indicates incorporation ofOSA into hydrated granules [77]

Succinic anhydride reacts with starch by refluxing withpyridin or by gelatinization of starch in aqueous pyridineis is followed by a reaction with succinic anhydride inpyridine Pyridine has a dual function in the reaction ac-tivates starch which makes it nucleophillic and reacts withsuccinic anhydride to form succinyl pyridinium in-termediate e intermediate reacts with starch generatingstarch succinate and pyridine as shown in Scheme 5 [78]

Mehboob et al [79] used succinic anhydride to modifythe native sorghum starch and acid-thinned starch Succi-nylation of starch introduces succinyl groups that havehydrophilic character to starch [79] is group weakens

O C N R N C O R O C N R N

H O O H

C OO

H

OH

H

OOH

HOH

H

HH

DMSO

OH

H

OOH

HOH

H

HHO C N

HR N C O R O C N R N

H O O H

C O

O

OH

H

OOH

HOH

H

HH

H O

n

+

n nStarch-based polyurethane

Starch

Prepolymer

Scheme 3 Preparation of starch-based polyurethane [70]

O

O

O

OH

O

H

HO

H

OOH

H

HHO

R=Hor

O

O O Na+ndash

OH

O

HRO

H

OOR

H

HRO

+

Scheme 4 Reaction showing starch modified with octenyl succinic anhydride (OSA)


internal bonding in starch granules and leads to solubili-zation of starch in cold water Research has shown thatsuccinylation reduced retrogradation in starches while thepeak cold paste and water-binding capacity and set backviscosities improved [77] Olayinka et al [80] demonstartedthat these parameters are increased by succinylation of redsorghum starch and decreased by modification of a whitesorghum starch e researcher stated that starch succinateshave advantages such as high viscocity greater thickeningpower and low gelatinization and retrogradation [80]Succinylated starches are used in preparation of nongellingcreams due to the increase in viscosity of starch Its im-proved hydrophilicity [79] makes them suitable for use as abinder in particleboards

Hydroxypropylation is a common etherification methodfor starch through treatment with propylene oxide in an al-kaline media [81] Starch reacts with propylene oxide to formthe hydroxylpropyl starch as shown in Scheme 6

Hydroxypropylation decreases the ability of starch torecrystallize which reduces the retrogradation property ofstarch yielding a derivative that is stable at high temperatures[82] Hydroxyl groups are substituted with hydroxylpropylgroups making its physicochemical properties similar tothose of the carboxymethylation method Hyroxypropylgroups disrupt inter- and intramolecular forces in starchthus breaking hydrogen bond is weakens the starchgranules leading to its flexibility of amorphous region Wateruptake increases and thus an increase in the swellability [83]Hydroxypropylation increases starch solubility in water andhas stabilized solubility [84] Hydroxypropylation reducesthe number of hydroxyl groups in starchis in turn reducesthe hydrophilic properties of particleboards formulated withthe hydropropylated starch is will reduce water absorp-tion and thickness selling of the particleboard

Native starches are present in semicrystalline granularforms with certain thermal properties and functionality thathave permitted its industrial use Starch requires high heat toundergo a transition process during which the granulesbreak down into a mixture of polymers-in-solution knownas gelatinization Sodium hydroxide solution reduces thetemperature required by the starch to gelatinize [85]

Sodium hydroxide is meant to stabilize the viscosity of starchadhesives when they are subjected to high shearing actionheat for prolonged periods or freeze-thaw cycles [86] Starchreacts with sodium hydroxide to produce a cationated starchas shown in Scheme 7

Other plasticizers apart fromwater and aqueous alkalineinclude salt solution such as calcium chloride and potassiumiodide [87] Starch a polyol reacts with borax to form aborax-starch complex [88] as illustrated in Scheme 8

Sodium hydroxide delignifies lignocellulose material bycleavage of the β-O-4 ether bond in which sodium cation andhydroxide ion participate [89] as illustrated in Scheme 9

Activated starch reacts with lignin in lignocellulose materialto form a plasticized starch blend [90] as shown in Figure 1

Delignification takes place during cellulosic ethanolproduction to form free cellulose hemicellulose and lignin[91] High concentration of sodium hydroxide convertscellulose and hemicellulose into organic acids furfural andhydroxymethyl furfural [92] An organic acid such as lacticacid has been used in crosslinking of starch and furfuralFurfurals were used as a substitute of formaldehyde inparticleboard formulation respectively Lignin hydroxylgroups are oxidized to carboxylic acid in the presence ofsodium hydroxide as a catalyst [93] Carboxylic acid reactswith starch hydroxyl groups to form an ester Ester for-mation is the main linkage point between the lignocellulosematerials and starch binders in the proposed compositeformulation for particleboard

Citric acid and sucrose are natural adhesives [45] Citricacid is an organic polycarboxylic acid which contains threecarboxyl groups used as cross-linking agent for woodthrough esterification [94] as shown in Figure 2

Liao et al [45] bonded sugarcane bagasse with com-mercial sucrose-based adhesive modified with citric acid inthe production of particleboard e board produced had a

NO OO

O NO

OStarch-OH

O NO

O

St C

O

CH2

CH2C

O

HON

H

+

++

Starch succinate

Succinyl pyridinium intermediateSuccinic anhydridePyridine

Scheme 5 Starch modification with succinate and pyridine

H2C+Stondash CHCH3

OOH

StOCH2CHCH3 + NaOHHydropropylationat pH 115

Scheme 6 Hydroxylpropylation of starch with propylene oxide


density of 045 gcm3 a low density particleboard [45] Boarddensity between 035 and 045 gcm3 produced modulus ofrapture (MOR) of 62Nmm2 [45] e particleboardshowed good thermal insulation properties when used asbuilding material for thermal insulation applications Par-ticleboards produced had a density of 040 gcm3 met the

requirement of Chinese national forestry industry standardSugarcane bagasse is rich in sugar-containing compoundsthat make it suitable for particleboards manufacturing [45]

Starch hydrolyzed with and acid followed with oxidationlead to the formation of aldehyde starch [95] as shown inScheme 10

O H

OH H

OH

CH2OH

H

O O

H

+ NaOH

O H

OH H

OH

CH2OndashNa+

H

O O

H nn

+ H2O

Scheme 7 Reaction between starch and sodium hydroxide

B

OH

OH

HO

HO

Na+ OH

OHO

O

B

O

OH

OHO

O

Na+ 2H2O+

ndash

ndash

+

Starch

Scheme 8 Starch molecules crosslinked with borax

O

OCH3

OCH3

R

OH

OMeMeO

Na+

H

OH

OHndash

ndashH2O

R

OMe

ONa

MeOOMe

OH

MeO

OH

OMe

OH

MeO

O

+

Scheme 9 Cleavage of the β-O-4 bond and formation of synringyl derivatives

HO

O

O

OH3C

O

OHCH2

HO

HOHO

O

CH3

HO

Figure 1 Ether bond formed between starch and lignocellulose material


OO

OH

OH

OH

O

HO OH

O

O

OO

OH

OH

OH

O

HO COOH

O OO

O

OH

OH

OH

O

HO

O

OH

OO

OH

OH

OH

O

O

Bridging reactionCellulose molecule

Figure 2 Reaction between citric acid and cellulose molecules [45]

O

O

O

O

O

O

CH2OH

CH2OHCH2OH

CH2OH

CH2OH

CH2OHCH2OHCH2OH

OH OH

OH

H

H

OH

OH

OH H

OH H

OH

HOH

H

H

OH

O

H

O

O

H

HHHO

H

H

OH

O

H

H

O OO

O

C

O

OHH

O

H

O OHO

H

n

+ n

NaIO4 HCl(aq)

Scheme 10 Reaction of acid hydrolysis and oxidation of starch

O

C

CH2OH

H

HO

O O O

HH

O

H

CH

O

CH2OH

H

OH

OH

O

O

HO

OH OH OH OH OH OH

Lignocellulosematerial

Acetal Hemiacetal

Figure 3 Acetal and hemiacetal bondage between lignocellulose material and modified starch


Starch dialdehyde reacts with lignocellulose material toform acetal and hemiacetal bondage [96 97] as proposed inFigure 3

2 Conclusion

Starch structural and functional diversity make it suitable fordifferent applications Various modifications will changeand improve functional properties of starch and facilitate itsutilization for different purposes Starch modified with otherchemicals is used as a substitute for formaldehyde-basedresin in particleboard formulations Hydroxyl group mod-ification in starch is achieved through the introduction ofalkyl groups or oxidation to carboxylic acidis reduces thehydroxyl functional groups that determine the water ab-sorption and thickness swelling which in turn affect themechanical properties of particleboard Functional groups inlignocellulose materials determine the water and thicknessswelling Interaction between modified starch-based resinand lignocellulose materials improve properties of parti-cleboard Mechanical strength of particleboard made fromstarch-based resin is due to reaction between starch andlignocellulose materials e hydroxyl group in starch andcarboxylic group in lignocellulose materials react throughcondensation polymerization to form ester linkages Es-terification produces hydrophobic material that reduceswater absorption Esterification also results in formation ofcovalent bonding that increases the interaction betweencomponents of particleboards is in turn increases themechanical properties of the particleboard Unmodifiedhydroxyl groups in both starch and lignocellulose materialsundergo etherification forming a covalent bond throughether bond Ether and ester linkages are covalent bondsstronger than hydrogen bonding found between the un-treated starch and lignocellulose materials Physical andmechanical properties of particleboards produced fromstarch-based adhesives are improved by crosslinking of thestarch and lignocellulose material using borax

Disclosure

is review is part of PhD research project without anyresearch funds

Conflicts of Interest

e authors declare no conflicts of interest

References

[1] T Salthammer S Mentese and R Marutzky ldquoFormaldehydein the indoor environmentrdquo Chemical Reviews vol 110 no 4pp 2536ndash2572 2010

[2] N S Ccediletin and N Ozmen ldquoUse of organosolv lignin inphenol-formaldehyde resins for particleboard productionrdquoInternational Journal of Adhesion and Adhesives vol 22 no 6pp 477ndash480 2002

[3] C A Finch and A Pizzi Wood Adhesives Chemistry andTechnology Marcel Dekkar New York NY USA 1984

[4] M Ghorbani F Liebner H W G Herwijnen et al ldquoLigninphenol formaldehyde resoles the impact of lignin type on

adhesive propertiesrdquo Journal for BioResource vol 11pp 6727ndash6741 2016

[5] A Pizzi ldquoRecent developments in eco-efficient bio-basedadhesives for wood bonding opportunities and issuesrdquoJournal of Adhesion Science and Technology vol 20 no 8pp 829ndash846 2006

[6] A Pizzi and K L Mittal Handbook of Adhesive TechnologyChapter 31 Marcel Dekker New York NY USA 2003

[7] R M Rowell Handbook of Wood Chemistry and WoodComposites CRC Press Boca Raton FL USA 2013

[8] Z Que T Furuno S Katoh and Y Nishino ldquoEffects of urea-formaldehyde resin mole ratio on the properties of parti-cleboardrdquo Building and Environment vol 42 no 3pp 1257ndash1263 2007

[9] F C Dupre M E Foucht W P Freese K D GabrielsonB D Gapud and H W Ingram ldquoCyclic urea formaldehydeprepolymer for use in phenol formaldehyde and melamineformaldehyde resin based bindersrdquo US Patent US 00549942002

[10] D J Merline S Vukusic and A A Abdala ldquoMelamineformaldehyde curing studies and reaction mechanismrdquoPolymer Journal vol 45 no 4 pp 413ndash419 2012

[11] Y Li C Ji Y Lu et al ldquoIn situ synthesis of carbong-C3N4composites for visible light catalysis by facile one-step py-rolysis of partially formaldehyde-modified dicyandiamiderdquoMaterials Chemistry and Physics vol 214 pp 28ndash33 2018

[12] S Boran M Usta and E Gumuskaya ldquoDecreasing formal-dehyde emission from medium density fiberboard panelsproduced by adding different amine compounds to ureaformaldehyde resinrdquo International Journal of Adhesion andAdhesives vol 31 no 7 pp 674ndash678 2011

[13] J I De Jong and J de Jonge ldquoe reaction of urea withformaldehyderdquo Recueil Des Travaux Chimiques Des Pays-Basvol 71 no 7 pp 643ndash660 2010

[14] N A Costa J Pereira J Ferra et al ldquoScavengers for achievingzero formaldehyde emission of wood-based panelsrdquo WoodScience and Technology vol 47 no 6 pp 1261ndash1272 2013

[15] A Marsal S Cuadros A M Manich F Izquierdo andJ Font ldquoReduction of the formaldehyde content in leatherstreated with formaldehyde resins by means of plant poly-phenolsrdquo Journal of Cleaner Production vol 148 pp 518ndash5262017

[16] A Takagaki K Fukai F Nanjo Y Hara M Watanabe andS Sakuragawa ldquoApplication of green tea catechins as form-aldehyde scavengersrdquo Journal for the Japan Wood Researchvol 46 p 237 2000

[17] E Bakar E Ulucam and A Cerkezkayabekir ldquoProtectiveeffects of proanthocyanidin and vitamin E against toxic effectsof formaldehyde in kidney tissuerdquo Biotechnic amp Histochem-istry vol 90 no 1 pp 69ndash78 2014

[18] Y B Hoong M T Paridah Y F Loh M P KohC A Luqman and A Zaidon ldquoAcacia mangium tannin asformaldehyde scavenger for low molecular weight phenol-formaldehyde resin in bonding tropical plywoodrdquo Journal ofAdhesion Science and Technology vol 24 no 8ndash10pp 1653ndash1664 2010

[19] B Meyer W E Johns and J K Woo ldquoFormaldehyde releasefrom sulfur-modified urea-formaldehyde resin systemsrdquoJournal for Forest Products vol 30 pp 24ndash31 1980

[20] K-H Kim S A Jahan and J-T Lee ldquoExposure to formal-dehyde and its potential human health hazardsrdquo Journal ofEnvironmental Science and Health Part C vol 29 no 4pp 277ndash299 2011


[21] K Lu L B Collins H Ru E Bermudez and J A SwenbergldquoDistribution of DNA adducts caused by inhaled formalde-hyde is consistent with induction of nasal carcinoma but notleukemiardquo Toxicological Sciences vol 116 no 2 pp 441ndash4512010

[22] M Hauptmann P A Stewart J H Lubin et al ldquoMortalityfrom lymphohematopoietic malignancies and brain canceramong embalmers exposed to formaldehyderdquo JNCI Journal ofthe National Cancer Institute vol 101 no 24 pp 1696ndash17082009

[23] R B Hayes A Blair P A Stewart R F Herrick andH Mahar ldquoMortality of US embalmers and funeral di-rectorsrdquo American Journal of Industrial Medicine vol 18no 6 pp 641ndash652 1990

[24] J Walrath and J F Fraumeni ldquoMortality patterns amongembalmersrdquo International Journal of Cancer vol 31 no 4pp 407ndash411 1983

[25] J Walrath and J F Fraumeni ldquoCancer and other causes ofdeath among embalmersrdquo Journal for Cancer Researchvol 44 no 10 pp 4638ndash4641 1984

[26] L Zhang L E B Freeman J Nakamura et al ldquoFormaldehydeand leukemia epidemiology potential mechanisms andimplications for risk assessmentrdquo Journal for Environmentaland Molecular Mutagenesis vol 51 pp 181ndash191 2010

[27] L E Pinkerton M Hein and L Stayner ldquoMortality among acohort of garment workers exposed to formaldehyde anupdaterdquo Occupational and Environmental Medicine vol 61no 3 pp 193ndash200 2004

[28] M Irle C Belloncle B Guezguez L R and R ChauvinldquoAn investigation of a ldquogreenrdquo extender for synthetic adhe-sivesrdquo in Proceedings of the ARBORA Conference pp 20-21Bordeaux France November 2008

[29] S Kim ldquoe reduction of formaldehyde and VOCs emissionfromwood-based flooring by green adhesive using cashew nutshell liquid (CNSL)rdquo Journal of Hazardous Materials vol 182no 1ndash3 pp 919ndash922 2010

[30] Y Liu and K Li ldquoChemical modification of soy protein forwood adhesivesrdquo Macromolecular Rapid Communicationsvol 23 no 13 pp 739ndash742 2002

[31] K F Patel H U Mehta and H C Srivastava ldquoKinetics andmechanism of oxidation of starch with sodium hypochloriterdquoJournal of Applied Polymer Science vol 18 no 2 pp 389ndash3991974

[32] D Gumul H Gambus and M Gibinski ldquoAir oxidation ofpotato starch over zinc (II) catalystrdquo Journal on CarbohydratePolymers vol 8 pp 45ndash50 2014

[33] Z Qiao J Gu S Lv J Cao H Tan and Y Zhang ldquoPrep-aration and properties of normal temperature cured starch-based wood adhesiverdquo Journal on BioResources vol 11pp 4839ndash4849 2016

[34] C Siau A Karim M Norziah and W Wan Rosli ldquoEffects ofcationization on DSC thermal profiles pasting and emulsi-fying properties of sago starchrdquo Journal of the Science of Foodand Agriculture vol 84 no 13 pp 1722ndash1730 2004

[35] F Xie L Yu H Liu and L Chen ldquoStarch modification usingreactive extrusionrdquo Journal on Starch vol 58 pp 131ndash1392016

[36] Z Huang J Lu X Li and Z Tong ldquoEffect of mechanicalactivation on physico-chemical properties and structure ofcassava starchrdquo Carbohydrate Polymers vol 68 no 1pp 128ndash135 2007

[37] S Emami A Perera V Meda and R T Tyler ldquoEffect ofmicrowave treatment on starch digestibility and physico-

chemical properties of three barley typesrdquo Food and Bio-process Technology vol 5 no 6 pp 2266ndash2274 2012

[38] G Lewandowicz T Jankowski and J Fornal ldquoEffect ofmicrowave radiation on physico-chemical properties andstructure of cereal starchesrdquo Carbohydrate Polymers vol 42no 2 pp 193ndash199 2000

[39] R Czechowska-Biskup B Rokita S Lotfy P Ulanski andJ M Rosiak ldquoDegradation of chitosan and starch by 360-kHzultrasoundrdquo Journal on Carbohydrate Polymers vol 60 no 2pp 175ndash184 2013

[40] Z Luo X Fu X He F Luo Q Gao and S Yu ldquoEffect ofultrasonic treatment on the physicochemical properties ofmaize starches differing in amylose contentrdquo Journal onStarchmdashStarke vol 60 no 11 pp 646ndash653 2013

[41] A Gunaratne and R Hoover ldquoEffect of heat-moisturetreatment on the structure and physicochemical properties oftuber and root starchesrdquo Carbohydrate Polymers vol 49no 4 pp 425ndash437 2002

[42] H-J Chung H S Lim and S-T Lim ldquoEffect of partialgelatinization and retrogradation on the enzymatic digestionof waxy rice starchrdquo Journal of Cereal Science vol 43 no 3pp 353ndash359 2006

[43] B Kaur F Ariffin R Bhat and A A Karim ldquoProgress instarch modification in the last decaderdquo Food Hydrocolloidsvol 26 no 2 pp 398ndash404 2012

[44] Y N Shariffa A A Karim A Fazilah and I S M ZaidulldquoEnzymatic hydrolysis of granular native and mildly heat-treated tapioca and sweet potato starches at sub-gelatinizationtemperaturerdquo Food Hydrocolloids vol 23 no 2 pp 434ndash4402009

[45] R Liao J Xu and K Umemura ldquoLow density sugarcanebagasse particleboard bonded with citric acid and sucroseeffect of board density and additiverdquo Journal for Bioresourcesvol 11 pp 2174ndash2185 2016

[46] M E Selamat O Sulaiman R Hashim et al ldquoMeasurementof some particleboard properties bonded with modifiedcarboxymethyl starch of oil palm trunkrdquo Measurementvol 53 pp 251ndash259 2014

[47] J Y Shi and Y Y Tang ldquoStudy on the rice straw-particleboardby starch-based API adhesiverdquo Advanced Materials Researchvol 113-116 pp 1017ndash1020 2010

[48] I Spiridon C-A Teaca and R Bodirlau ldquoPreparation andcharacterization of adipic acid-modified starch microparti-clesplasticized starch composite films reinforced by ligninrdquoJournal of Materials Science vol 46 no 10 pp 3241ndash32512010

[49] M Blackwell H Kang A omas and P Infante ldquoForm-aldehyde evidence of carcinogenicityrdquo American IndustrialHygiene Association Journal vol 42 pp 34ndash46 1981

[50] J A Swenberg B C Moeller and K Lu ldquoFormaldehydecarcinogenicity research 30 years and counting for mode ofaction epidemiology and cancer risk assessmentrdquo Journal onToxicologic Pathology vol 41 pp 143ndash148 2013

[51] USNTP ldquoNational toxicology program (NTP)rdquo Report onCarcinogens Depart-ment of Health and Human ServicesPublic Health Service National Toxicology Pro-Gram USNTPPatuxent River MD USA 12th edition 2011

[52] X Mo E Cheng DWang and X S Sun ldquoPhysical propertiesof medium-density wheat straw particleboard using differentadhesivesrdquo Industrial Crops and Products vol 18 no 1pp 47ndash53 2003

[53] W A Mitchell ldquoStarch solubilityrdquo Journal of Chemical Ed-ucation vol 54 no 2 p 132 1977


[54] P M Ganorkar and A S Kulkarni ldquoStudies on preparationand functional properties of carboxymethyl starch fromsorghumrdquo Journal for Food Research vol 20 pp 2205ndash22102013

[55] S A Roberts and R E Cameron ldquoe effects of concentrationand sodium hydroxide on the rheological properties of potatostarch gelatinisationrdquo Carbohydrate Polymers vol 50 no 2pp 133ndash143 2002

[56] M Wooton and P Ho ldquoAlkali gelatinisation of wheat starchrdquoJournal for StarchmdashStaErke vol 41 pp 261ndash265 1989

[57] H Judawisastra R D R Sitohang L Marta and MardiyatildquoWater absorption and its effect on the tensile properties oftapioca starchpolyvinyl alcohol bioplasticsrdquo IOP ConferenceSeries Materials Science and Engineering vol 223 Article ID012066 2017

[58] S H Imam L Mao L Chen and R V Greene ldquoWoodadhesive from crosslinked poly(vinyl alcohol) and partiallygelatinized starch preparation and propertiesrdquoStarchmdashStarke vol 51 no 6 pp 225ndash229 1999

[59] Z Pan A Cathcart and D Wang ldquoProperties of particle-board bond with rice bran and polymeric methylene diphenyldiisocyanate adhesivesrdquo Industrial Crops and Productsvol 23 no 1 pp 40ndash45 2006

[60] Q Xu J Wen and Z Wang ldquoPreparation and properties ofcassava starch-based wood adhesivesrdquo Journal on Bio-Resources vol 11 pp 6756ndash6767 2016

[61] Z Zhu and R Zhuo ldquoControlled release of carboxylic-con-taining herbicides by starch-g-poly(butyl acrylate)rdquo Journal ofApplied Polymer Science vol 81 no 6 pp 1535ndash1543 2001

[62] P Liu and Z Su ldquoSurface-initiated atom transfer radicalpolymerization (SI-ATRP) of n-butyl acrylate from starchgranulesrdquo Carbohydrate Polymers vol 62 no 2 pp 159ndash1632005

[63] K C Gupta and S Sahoo ldquoGraft copolymerization of acry-lonitrile and ethyl methacrylate comonomers on celluloseusing ceric ionsrdquo Biomacromolecules vol 2 no 1 pp 239ndash247 2001

[64] Y-P Wu Q Qi G-H Liang and L-Q Zhang ldquoA strategy toprepare high performance starchrubber composites in situmodification during latex compounding processrdquo Carbohy-drate Polymers vol 65 no 1 pp 109ndash113 2006

[65] S H Imam S H Gordon L Mao and L Chen ldquoEnviron-mentally friendly wood adhesive from a renewable plantpolymer characteristics and optimizationrdquo Polymer Degra-dation and Stability vol 73 no 3 pp 529ndash533 2001

[66] X Li Z Cai J E Winandy and A H Basta ldquoSelectedproperties of particleboard panels manufactured from ricestraws of different geometriesrdquo Bioresource Technologyvol 101 no 12 pp 4662ndash4666 2010

[67] X Erdocia R Prado M A Corcuera and J Labidi ldquoBasecatalyzed depolymerization of lignin influence of organosolvlignin naturerdquo Biomass and Bioenergy vol 66 pp 379ndash3862014

[68] A B Akinyemi J O Afolayan and E O Oluwatobi ldquoSomeproperties of composite corn cob and sawdust particleboardsrdquo Construction and Building Materials vol 127pp 436ndash441 2016

[69] J Cui et al ldquoEnhancement of mechanical strength of parti-cleboard using environmentally friendly pine (Pinus pinaster L)tannin adhesives with cellulose nanofibersrdquo Journal for Annals ofForest Science vol 72 no 1 pp 27ndash32 2015

[70] S L P Jordan ldquoInactivation of glutaraldehyde by reactionwith sodium bisulfiterdquo Journal of Toxicology And Environ-mental Health vol 47 no 3 pp 299ndash309 1996

[71] M Barikani and M Mohammadi ldquoSynthesis and charac-terization of starch-modified polyurethanerdquo CarbohydratePolymers vol 68 no 4 pp 773ndash780 2007

[72] F Zia K M Zia M Zuber S Kamal and N Aslam ldquoStarchbased polyurethanes a critical review updating recent liter-aturerdquo Carbohydrate Polymers vol 134 pp 784ndash798 2015

[73] J Fiorelli D D L Sartori J C M Cravo et al ldquoSugarcanebagasse and castor oil polyurethane adhesive-based particu-late compositerdquo Materials Research vol 16 no 2 pp 439ndash446 2013

[74] R M De Barros Filho L M Mendes K M NovackL O Aprelini and V R Botaro ldquoHybrid chipboard panelsbased on sugarcane bagasse urea formaldehyde and mela-mine formaldehyde resinrdquo Industrial Crops and Productsvol 33 no 2 pp 369ndash373 2011

[75] M C Sweedman M J Tizzotti C Schafer and R G GilbertldquoStructure and physicochemical properties of octenyl succinicanhydride modified starches a reviewrdquo Carbohydrate Poly-mers vol 92 no 1 pp 905ndash920 2013

[76] L Altuna M L Herrera and M L Foresti ldquoSynthesis andcharacterization of octenyl succinic anhydride modifiedstarches for food applications A review of recent literaturerdquoFood Hydrocolloids vol 80 pp 97ndash110 2018

[77] Z Sui K C Huber and J N BeMiller ldquoEffects of the order ofaddition of reagents and catalyst on modification of maizestarchesrdquo Carbohydrate Polymers vol 96 no 1 pp 118ndash1302013

[78] P Bhandari and R S Singhal ldquoStudies on the optimisation ofpreparation of succinate derivatives from corn and amaranthstarchesrdquo Carbohydrate Polymers vol 47 no 3 pp 277ndash2832002

[79] S Mehboob T M Ali F Alam and A Hasnain ldquoDualmodification of native white sorghum (sorghum bicolor)starch via acid hydrolysis and succinylationrdquo LWTmdashFoodScience and Technology vol 64 no 1 pp 459ndash467 2015

[80] O O Olayinka B I Olu-Owolabi and K O AdebowaleldquoEffect of succinylation on the physicochemical rheologicalthermal and retrogradation properties of red and whitesorghum starchesrdquo Food Hydrocolloids vol 25 no 3pp 515ndash520 2011

[81] J Singh L Kaur and O J McCarthy ldquoFactors influencing thephysico-chemical morphological thermal and rheologicalproperties of some chemically modified starches for foodapplicationsmdasha reviewrdquo Food Hydrocolloids vol 21 no 1pp 1ndash22 2007

[82] J Pal R S Singhal and P R Kulkarni ldquoPhysicochemicalproperties of hydroxypropyl derivative from corn and ama-ranth starchrdquo Carbohydrate Polymers vol 48 no 1 pp 49ndash53 2002

[83] N Masina Y E Choonara P Kumar et al ldquoA review of thechemical modification techniques of starchrdquo CarbohydratePolymers vol 157 pp 1226ndash1236 2017

[84] A Besheer G Hause J Kressler and K Mader ldquoHydro-phobically modified hydroxyethyl starch synthesis charac-terization and aqueous self-assembly into nano-sizedpolymeric micelles and vesiclesrdquo Biomacromolecules vol 8no 2 pp 359ndash367 2007

[85] I D Evans and D R Haisman ldquoe effect of solutes on thegelatinization temperature range of potato starchrdquoStarchmdashStarke vol 34 no 7 pp 224ndash231 1982

[86] A A Ragheb I Abdel-alouth and S Tawfik ldquoGelatini-zation of starch in aqueous alkaline solutionsrdquoStarchmdashStarke vol 47 no 9 pp 338ndash345 1995


[87] J Jane ldquoStarch properties modifications and applicationsrdquoJournal of Macromolecular Science Part A vol 32 no 4pp 751ndash757 1995

[88] P Erdem E A Bursali and M Yurdakoc ldquoPreparation andcharacterization of tannic acid resin study of boron ad-sorptionrdquo Environmental Progress amp Sustainable Energyvol 32 no 4 pp 1036ndash1044 2012

[89] V M Roberts V Stein T Reiner A Lemonidou X Li andJ A Lercher ldquoTowards quantitative catalytic lignin de-polymerizationrdquo ChemistrymdashA European Journal vol 17no 21 pp 5939ndash5948 2011

[90] R-L Wu X-L Wang F Li H-Z Li and Y-Z Wang ldquoGreencomposite films prepared from cellulose starch and lignin inroom-temperature ionic liquidrdquo Bioresource Technologyvol 100 no 9 pp 2569ndash2574 2009

[91] Z Wang D R Keshwani A P Redding and J J ChengldquoSodium hydroxide pretreatment and enzymatic hydrolysis ofcoastal Bermuda grassrdquo Bioresource Technology vol 101no 10 pp 3583ndash3585 2010

[92] D B Hodge M N Karim D J Schell and J D McMillanldquoSoluble and insoluble solids contributions to high-solidsenzymatic hydrolysis of lignocelluloserdquo Bioresource Tech-nology vol 99 no 18 pp 8940ndash8948 2008

[93] X Gu C Kanghua H Ming Y Shi and Z Li ldquoLa-modifiedSBA-15H2O2 systems for the microwave assisted oxidation oforganosolv beech wood ligninrdquo Maderas Ciencia YTecnologıa vol 14 no 1 pp 31ndash41 2012

[94] S B Vukusic D Katovic C Schramm J Trajkovic andB Sefc ldquoPolycarboxylic acids as non-formaldehyde anti-swelling agents for woodrdquo Holzforschung vol 60 no 4pp 439ndash444 2006

[95] Y Zuo W Liu J Xiao X Zhao Y Zhu and Y WuldquoPreparation and characterization of dialdehyde starch byone-step acid hydrolysis and oxidationrdquo International Journalof Biological Macromolecules vol 103 pp 1257ndash1264 2017

[96] T Saito and A Isogai ldquoIntroduction of aldehyde groups onsurfaces of native cellulose fibers by TEMPO-mediated oxi-dationrdquo Colloids and Surfaces A Physicochemical and Engi-neering Aspects vol 289 no 1ndash3 pp 219ndash225 2006

[97] B Sun Q Hou Z Liu and Y Ni ldquoSodium periodate oxi-dation of cellulose nanocrystal and its application as a paperwet strength additiverdquo Cellulose vol 22 no 2 pp 1135ndash11462015


TribologyAdvances in

Hindawiwwwhindawicom Volume 2018


International Journal ofInternational Journal ofPhotoenergy


Journal of

Chemistry


Advances inPhysical Chemistry

Hindawiwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2018

Bioinorganic Chemistry and ApplicationsHindawiwwwhindawicom Volume 2018

SpectroscopyInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Medicinal ChemistryInternational Journal of


NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Applied ChemistryJournal of



Biochemistry Research International


Enzyme Research


Journal of

SpectroscopyAnalytical ChemistryInternational Journal of


MaterialsJournal of



BioMed Research International Electrochemistry

International Journal of


Na

nom

ate

ria

ls


Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

e most commonly used scavangers are compoundscontaining amine such as urea ammonia melamine anddicyandiamide [9] Melamine reacts with formaldehyde toform methylolamine as shown in equation (1) [10]

C3H6N6 + CH2O⟶ C4H8N6O (1)

Dicyandiamide reacts with two moles of formaldehydeas illustrated in equation (2) to form methyloldicyanamides[11]

C2H4N4 + 2CH2O⟶ C4H6N4O (2)

Urea reacts with formaldehyde to form mono-methylolurea as shown in equation (3) [12 13] Ureaformaldehyde resin is used in formulation of particleboardas a binder other than a scavanger

CO NH2( 11138572 + CH2O⟶ C2H6N2O2 (3)

Sodium metabisulphite (Na2S2O5) is a scavenger used inparticleboards produced with urea formaldehyde and mel-amine formaldehyde resins Sodium metabisulphite reactswith water to form sodium hydrogen sulfite as shown inequation (4)

Na2S2O5 + H2O⟶ 2NaHSO3 (4)

Sodium metabisulphite reacts with formaldehyde as ascavenger to form a bisulfite adduct [14] as shown inequation (5)

HCHO + NaHSO3⟶ HOCH2SO3Na (5)

Sodium hydrogen sulfite also reacts with sodium hy-droxide to form sodium sulfite as shown in equation (6)

NaHSO3 + NaOH⟶ H2O + Na2SO3 (6)

Sodium sulfite scavenger formaldehyde in the presenceof water to form bisulfite adduct as in equation (7) [14]

HCHO + Na2SO3 + H2O⟶ NaOH + NaSO3CH2OH(7)

Ammonia is a good scavenger for the emitted formal-dehyde [15] Green tea catechin as a formaldehyde scavengerreduced formaldehyde from plywood manufactured withformaldehyde-based resin Green tea extract reducedformaldehyde emissions from plywood [16] Proanthocya-nidic was found to protect kidney tissue against formalde-hyde [17] Tannin was mixed with low molecular phenol-formaldehyde resin in manufacture of plywood It was usedto scavenge against emitted formaldehyde [18]

Prolonged human exposure of formaldehyde lead tochronic toxicity and cancer [12 19] Formaldehyde can causenasopharyngeal cancer [20] Lu et al [21] reported on gen-otoxic and cytotoxic modes of action for the carcinogenesis ofinhaled formaldehyde in respiratory nasal epithelium [21] Anincreased incidence of myeloid leukemia has been reported

Increased exposure of formaldehyde to workers in a fu-neral homes resulted in mortality from myeloid leukemia [22]and lymphohematopoietic malignancies [23ndash25] e mostconsistent pattern was death as a result of myeloid leukemis

[26] A study of 11039 textile workers produced a certainrelationship between the duration of formaldehyde exposureand leukemia-related deaths [27] e exposure assessmentbased on 594 workers produced the mean exposure levelsbetween 009 and 020 ppm and the levels were relativelyconstant with no peaks or intermittent exposures Leukemiahad the highest standardized mortality ratio (SMR) withmajority of occurrences from garment factory e epide-miological literature on formaldehyde and leukemia is ex-tensive Many studies have shown a correlation betweenformaldehyde and cancer-related complications [26]

13 Use of Starch and Starch Derivatives as Substitutes forParticleboard Formulation Adhesive technology is movingtowards replacements of formaldehyde-based adhesives touse of biobased resources [28ndash30] Various types of starchmodification on its crystalline nature include chemicaltreatments such as oxidation using hypochlorite [31] and air[32] esterification [33] and cationization [34 35] Physicalmodification of starch includes mechanical activation [36]microwave [37 38] ultrasonic degradation [39 40] heat-moisture treatment [41] and enzymatic treatment [42ndash44]e modified starch has been utilized in particleboardformulation [45ndash48]

Selamat et al [46] compared physical and mechanicalproperties of particleboard formulated from rubberwoodwith urea formaldehydes and native starch separately asbinderse native starch was extracted from oil palm trunkParticleboard bonded with formaldehyde showed thicknessswelling of 1117 and water absorption of 8208 whencompared to the native starch with thickness swelling of8208 and water absorption of 17452 [46] is showsthat formaldehyde-based resin is more than twice better thanthe carboxymethyl starch although the main drawback isemission of formaldehyde Formaldehyde has been found tohave carcinogenic properties [21 49ndash51] High water ab-sorption of particleboard formulated with the carbox-ymethyl starch may be attributed to the presence of hydroxylgroups Hydroxyl groups form hydrogen bonding withwater is increases water absorption and thicknessswelling thus affecting mechanical properties of the parti-cleboards Methylene diphenyl diisocyanate (MDI) weresmall and had better mechanical and chemical bondingability [52] Improvement in chemical bonding results inimprovement in mechanical properties of the particleboardformulated

Natural starch is in the disorganized metastable state andas such is easily dispersed in warm water [53] Carbox-ymethylation therefore is a chemical modification methodthat is vital and versatile for transforming starch Trans-formation of starch involves provision of water solublepolymers and intermediate of valuable functional attributes[54] Carboxymethylation of starch (CMS) involves partialsubstitution of hydroxyl group (-OH) with ether group (-O-CH2COOH) Starch reacts with monochloroacetic acid toproduce carboxymethyl in the presence of sodium hydroxidein three different steps Step one involves reaction of starchwith starch as shown in equation (8)



















OH

SO3ndash

(CH2)3ndashC

OH

SO3ndash

(11)




N

N N

NN

N

CH2

CH2

CH2

CH2

CH2 CH2

H3CO

H3CO

OCH3

OCH3

OCH3 OCH3

HO Wood

HO Starch

HO PVOH

NN

NN

N

N

CH2CH2

CH2CH2

CH2

CH2

O O

O O

O

O

Starch HOVP

Wood

Starch

WoodPVOH

H3C OH+

Catalyst


OHO

OH

H

O

H

H

HH

OHC

OHC

OO

O

H

O

H

H

HH

CHO

OH

OHC

OH

n

+

+

n


H








H O O H

C OO

H

OH

H

OOH

HOH

H

HH

DMSO

OH

H

OOH

HOH

H

HHO C N


H O O H

C O

O

OH

H

OOH

HOH

H

HH

H O

n

+


Starch

Prepolymer


O

O

O

OH

O

H

HO

H

OOH

H

HHO

R=Hor

O

O O Na+ndash

OH

O

HRO

H

OOR

H

HRO

+














NO OO

O NO

OStarch-OH

O NO

O

St C

O

CH2

CH2C

O

HON

H

+

++

Starch succinate



H2C+Stondash CHCH3

OOH







O H

OH H

OH

CH2OH

H

O O

H

+ NaOH

O H

OH H

OH

CH2OndashNa+

H

O O

H nn

+ H2O


B

OH

OH

HO

HO

Na+ OH

OHO

O

B

O

OH

OHO

O

Na+ 2H2O+

ndash

ndash

+

Starch


O

OCH3

OCH3

R

OH

OMeMeO

Na+

H

OH

OHndash

ndashH2O

R

OMe

ONa

MeOOMe

OH

MeO

OH

OMe

OH

MeO

O

+


HO

O

O

OH3C

O

OHCH2

HO

HOHO

O

CH3

HO



OO

OH

OH

OH

O

HO OH

O

O

OO

OH

OH

OH

O

HO COOH

O OO

O

OH

OH

OH

O

HO

O

OH

OO

OH

OH

OH

O

O



O

O

O

O

O

O

CH2OH

CH2OHCH2OH

CH2OH

CH2OH

CH2OHCH2OHCH2OH

OH OH

OH

H

H

OH

OH

OH H

OH H

OH

HOH

H

H

OH

O

H

O

O

H

HHHO

H

H

OH

O

H

H

O OO

O

C

O

OHH

O

H

O OHO

H

n

+ n

NaIO4 HCl(aq)


O

C

CH2OH

H

HO

O O O

HH

O

H

CH

O

CH2OH

H

OH

OH

O

O

HO

OH OH OH OH OH OH


Acetal Hemiacetal




2 Conclusion


Disclosure




References













































































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





















OH

SO3ndash

(CH2)3ndashC

OH

SO3ndash

(11)




N

N N

NN

N

CH2

CH2

CH2

CH2

CH2 CH2

H3CO

H3CO

OCH3

OCH3

OCH3 OCH3

HO Wood

HO Starch

HO PVOH

NN

NN

N

N

CH2CH2

CH2CH2

CH2

CH2

O O

O O

O

O

Starch HOVP

Wood

Starch

WoodPVOH

H3C OH+

Catalyst


OHO

OH

H

O

H

H

HH

OHC

OHC

OO

O

H

O

H

H

HH

CHO

OH

OHC

OH

n

+

+

n


H








H O O H

C OO

H

OH

H

OOH

HOH

H

HH

DMSO

OH

H

OOH

HOH

H

HHO C N


H O O H

C O

O

OH

H

OOH

HOH

H

HH

H O

n

+


Starch

Prepolymer


O

O

O

OH

O

H

HO

H

OOH

H

HHO

R=Hor

O

O O Na+ndash

OH

O

HRO

H

OOR

H

HRO

+














NO OO

O NO

OStarch-OH

O NO

O

St C

O

CH2

CH2C

O

HON

H

+

++

Starch succinate



H2C+Stondash CHCH3

OOH







O H

OH H

OH

CH2OH

H

O O

H

+ NaOH

O H

OH H

OH

CH2OndashNa+

H

O O

H nn

+ H2O


B

OH

OH

HO

HO

Na+ OH

OHO

O

B

O

OH

OHO

O

Na+ 2H2O+

ndash

ndash

+

Starch


O

OCH3

OCH3

R

OH

OMeMeO

Na+

H

OH

OHndash

ndashH2O

R

OMe

ONa

MeOOMe

OH

MeO

OH

OMe

OH

MeO

O

+


HO

O

O

OH3C

O

OHCH2

HO

HOHO

O

CH3

HO



OO

OH

OH

OH

O

HO OH

O

O

OO

OH

OH

OH

O

HO COOH

O OO

O

OH

OH

OH

O

HO

O

OH

OO

OH

OH

OH

O

O



O

O

O

O

O

O

CH2OH

CH2OHCH2OH

CH2OH

CH2OH

CH2OHCH2OHCH2OH

OH OH

OH

H

H

OH

OH

OH H

OH H

OH

HOH

H

H

OH

O

H

O

O

H

HHHO

H

H

OH

O

H

H

O OO

O

C

O

OHH

O

H

O OHO

H

n

+ n

NaIO4 HCl(aq)


O

C

CH2OH

H

HO

O O O

HH

O

H

CH

O

CH2OH

H

OH

OH

O

O

HO

OH OH OH OH OH OH


Acetal Hemiacetal




2 Conclusion


Disclosure




References













































































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls









H O O H

C OO

H

OH

H

OOH

HOH

H

HH

DMSO

OH

H

OOH

HOH

H

HHO C N


H O O H

C O

O

OH

H

OOH

HOH

H

HH

H O

n

+


Starch

Prepolymer


O

O

O

OH

O

H

HO

H

OOH

H

HHO

R=Hor

O

O O Na+ndash

OH

O

HRO

H

OOR

H

HRO

+














NO OO

O NO

OStarch-OH

O NO

O

St C

O

CH2

CH2C

O

HON

H

+

++

Starch succinate



H2C+Stondash CHCH3

OOH







O H

OH H

OH

CH2OH

H

O O

H

+ NaOH

O H

OH H

OH

CH2OndashNa+

H

O O

H nn

+ H2O


B

OH

OH

HO

HO

Na+ OH

OHO

O

B

O

OH

OHO

O

Na+ 2H2O+

ndash

ndash

+

Starch


O

OCH3

OCH3

R

OH

OMeMeO

Na+

H

OH

OHndash

ndashH2O

R

OMe

ONa

MeOOMe

OH

MeO

OH

OMe

OH

MeO

O

+


HO

O

O

OH3C

O

OHCH2

HO

HOHO

O

CH3

HO



OO

OH

OH

OH

O

HO OH

O

O

OO

OH

OH

OH

O

HO COOH

O OO

O

OH

OH

OH

O

HO

O

OH

OO

OH

OH

OH

O

O



O

O

O

O

O

O

CH2OH

CH2OHCH2OH

CH2OH

CH2OH

CH2OHCH2OHCH2OH

OH OH

OH

H

H

OH

OH

OH H

OH H

OH

HOH

H

H

OH

O

H

O

O

H

HHHO

H

H

OH

O

H

H

O OO

O

C

O

OHH

O

H

O OHO

H

n

+ n

NaIO4 HCl(aq)


O

C

CH2OH

H

HO

O O O

HH

O

H

CH

O

CH2OH

H

OH

OH

O

O

HO

OH OH OH OH OH OH


Acetal Hemiacetal




2 Conclusion


Disclosure




References













































































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls















NO OO

O NO

OStarch-OH

O NO

O

St C

O

CH2

CH2C

O

HON

H

+

++

Starch succinate



H2C+Stondash CHCH3

OOH







O H

OH H

OH

CH2OH

H

O O

H

+ NaOH

O H

OH H

OH

CH2OndashNa+

H

O O

H nn

+ H2O


B

OH

OH

HO

HO

Na+ OH

OHO

O

B

O

OH

OHO

O

Na+ 2H2O+

ndash

ndash

+

Starch


O

OCH3

OCH3

R

OH

OMeMeO

Na+

H

OH

OHndash

ndashH2O

R

OMe

ONa

MeOOMe

OH

MeO

OH

OMe

OH

MeO

O

+


HO

O

O

OH3C

O

OHCH2

HO

HOHO

O

CH3

HO



OO

OH

OH

OH

O

HO OH

O

O

OO

OH

OH

OH

O

HO COOH

O OO

O

OH

OH

OH

O

HO

O

OH

OO

OH

OH

OH

O

O



O

O

O

O

O

O

CH2OH

CH2OHCH2OH

CH2OH

CH2OH

CH2OHCH2OHCH2OH

OH OH

OH

H

H

OH

OH

OH H

OH H

OH

HOH

H

H

OH

O

H

O

O

H

HHHO

H

H

OH

O

H

H

O OO

O

C

O

OHH

O

H

O OHO

H

n

+ n

NaIO4 HCl(aq)


O

C

CH2OH

H

HO

O O O

HH

O

H

CH

O

CH2OH

H

OH

OH

O

O

HO

OH OH OH OH OH OH


Acetal Hemiacetal




2 Conclusion


Disclosure




References













































































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls







O H

OH H

OH

CH2OH

H

O O

H

+ NaOH

O H

OH H

OH

CH2OndashNa+

H

O O

H nn

+ H2O


B

OH

OH

HO

HO

Na+ OH

OHO

O

B

O

OH

OHO

O

Na+ 2H2O+

ndash

ndash

+

Starch


O

OCH3

OCH3

R

OH

OMeMeO

Na+

H

OH

OHndash

ndashH2O

R

OMe

ONa

MeOOMe

OH

MeO

OH

OMe

OH

MeO

O

+


HO

O

O

OH3C

O

OHCH2

HO

HOHO

O

CH3

HO



OO

OH

OH

OH

O

HO OH

O

O

OO

OH

OH

OH

O

HO COOH

O OO

O

OH

OH

OH

O

HO

O

OH

OO

OH

OH

OH

O

O



O

O

O

O

O

O

CH2OH

CH2OHCH2OH

CH2OH

CH2OH

CH2OHCH2OHCH2OH

OH OH

OH

H

H

OH

OH

OH H

OH H

OH

HOH

H

H

OH

O

H

O

O

H

HHHO

H

H

OH

O

H

H

O OO

O

C

O

OHH

O

H

O OHO

H

n

+ n

NaIO4 HCl(aq)


O

C

CH2OH

H

HO

O O O

HH

O

H

CH

O

CH2OH

H

OH

OH

O

O

HO

OH OH OH OH OH OH


Acetal Hemiacetal




2 Conclusion


Disclosure




References













































































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




OO

OH

OH

OH

O

HO OH

O

O

OO

OH

OH

OH

O

HO COOH

O OO

O

OH

OH

OH

O

HO

O

OH

OO

OH

OH

OH

O

O



O

O

O

O

O

O

CH2OH

CH2OHCH2OH

CH2OH

CH2OH

CH2OHCH2OHCH2OH

OH OH

OH

H

H

OH

OH

OH H

OH H

OH

HOH

H

H

OH

O

H

O

O

H

HHHO

H

H

OH

O

H

H

O OO

O

C

O

OHH

O

H

O OHO

H

n

+ n

NaIO4 HCl(aq)


O

C

CH2OH

H

HO

O O O

HH

O

H

CH

O

CH2OH

H

OH

OH

O

O

HO

OH OH OH OH OH OH


Acetal Hemiacetal




2 Conclusion


Disclosure




References













































































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls





2 Conclusion


Disclosure




References













































































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls


























































































Journal of

Chemistry





Journal of

Volume 2018






Volume 2018




Journal of






Enzyme Research


Journal of



MaterialsJournal of






Na

nom

ate

ria

ls




formaldehyde use and alternative biobased binders for...

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