09 silicone nanocoatings-dubois-u mons
TRANSCRIPT
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Silicone Nanocoatings electrical properties, anti- adhesion and fire
resistance Pr. Philippe DUBOIS
Center of Innovation and Research in Materials and Polymers
MATERIA NOVA Research Center & UNIVERSITY of MONS
Place du Parc 20, 7000 Mons Belgium
http://morris.umons.ac.be/CIRMAP
NANORA seminar 'Using nanotechnologies to optimise your coatings, SIRRIS, Seraing, January 15th, 2015
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Nanocomposites : Definition and Generalities
Nanocomposite : heterophasic system where the dispersed phase
(of a different nature than the continuous phase)
has at least one of its dimensions in the order of a few nanometers
3 nanodimensions : nanosized "isotropic" particles - metallic : Ag, ZnO, metal oxides, - inorganic : POSS, CdS, SiO2, Ca/Mg(OH)2, ferrites, - organic : carbon black, 2 nanodimensions : nanotubes, nanofibers and nanowhiskers - inorganic : sepiolite, halloysites - organic : carbon nanotubes/nanofibers, cellulose nanowhiskers and microfibers, 1 nanodimension : nanolayers - organic : exfoliated graphite, cristalline starch nanoplatelets, - inorganic : layered double hydroxides, layered silicates/clays,
Continuous phase : metal, ceramic, polymer,
Dispersed phase : nanofiller(s)
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~ 1-2 nm
Few microns
Single-wall nanotubes
~ 2 - 50 nm
TEM images of various MWNTs
Multi-wall nanotubes
Carbon Nanotubes
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Polymer Nanocomposites : Definition
Heterophasic polymer-based materials
where the dispersed phase, i.e. nanofiller(s), has
at least one of its three dimensions
in the order of a few nanometers
However,
-ALL nanofillers do form aggregates and even larger (m-size) agglomerates
- At best, in polymer matrices, nanofiller dispersion/individualization can be reached at filler content of max. 10 wt% (depending on filler geometry and shape factor)
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from m-size to >>> thousands aggregates individual nanoparticles
Nanocomposites : the Processing Challenge
Polymer
Huge polymer-nanofiller interface
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Synthetic MWNTs as produced via CCVD
NC 7000 (CNTs) from Nanocyl 0.1 10 m
10 nm
Characterization
Property Unit Value Method of Measurement
Average diameter
Average Length
Carbon Purity
Metal Oxide (impurity)
Amorphous Carbon &
Carbon Shells (impurity)
Surface area
nanometers
microns
% %
%
m2/g
9.5
1.5
90
10
Not detectable
250-300
TEM
TEM
TGA
TGA
HRTEM
BET
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Studied silicone : hydrosilylation curing Sylgard 184 PDMS*
Si O Si O SiH
p
Si O m
Si O Si O Sip
SiO
m +
Optimized reaction conditions (time, T(C), molar ratio, catalyst, etc.) :
highly cross-linked & stable
PDMS networks 100-500m thick PDMS coatings
PART A
PART B
Pt catalyst
* From Dow Corning
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Comp. 1 (Nature-%)
Comp. 2 (Nature -%)
Comp. 3 (Nature-%)
Other components
Dynamic viscosity
Part A (10 parts)
Vinyl-ended PDMS : SFD 117
67%
VQM 1 (2% vinyl)
31%
Pt Catalyst
0.14%
Volatile cyclics and
low MW silicone (1.5%)
and xylne (0.7%)
4817 cP
Part B
(1 part)
Si-H containing
PDMS (0.76% H) :
MDD(H) 60%
SFD 117
39%
Inhibitor
1% -
89.1 cP
Sylgard 184 resin : hydrosilylation curing resin
CH2 CH ( CH2)n ( Si O ) 434Si ( CH2)2n CH CH2
SFD 117 :
Si O Si O
Me Me
Me H
( ) ( )MDD(H) : SiSi O
Si O Si O Si
Me
O
O
SiO
Si
O
: VQM 1
Si
SiO
Si
O SiO
O
Inhibitor :
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Production of nanofiller-modified silicone systems
mixing for 2h (by mechanical stirring at
1200 rpm, r.t.) of part A + nanofillers Addition of part B, mixing, casting and
then curing for min. 6h.
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Viscosity evolution of CNTs-filled PDMS (part A) with shear rate
- Huge increase of the viscosity at lower shear rate - Rheothinning effect !!
Moreira L. et al., Macromolecules, 43, 1467(2010)
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Viscosity evolution of CNTs-filled PDMS with shear rate
In other words : high interests of MWCNTs for coating application Easiness of the application process Possibility to brush-paint the PDMS formulation (before cross-linking reaction) in every position (e.g. floor, walls, ceiling)
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Remarkable affinity between MWNTs and PDMS
OSi
OSi
OSi
OSi
O
Me MeMe MeMe Me MeMe
Si Si Si Si OH OH O O
Silica
PDMS
fully confirmed by theoretical modeling
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Crosslinked PDMS + 0.5
wt% MWNTs
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CNT-filled Silicone : ELECTRICAL CONDUCTIVITY
-14
-12
-10
-8
-6
-4
-2
00 0,5 1 1,5 2 2,5 3
Filler content (wt%)
LOG
Con
duct
ivity
(S.c
m-1
)
PDMS + PMWNTs 7000 (from NANOCYL)
2-point method
GOOD CONDUCTIVITY AT LOW FILLER CONTENT
NANOCYL (Belgium) : Commercial STATICYL Grade
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Tests of different methods to apply the (nano)coating
By brush By injection
By spray on different supports, incl. foams
The core of the material (e.g. foam) is
not modified
NANOCYL (Belgium) : Commercial Grade NC7500 Courtesy from Nanocyl
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CNT-filled Silicone : FIRE RESISTANCE BEHAVIOR
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Flame-resistance testing
Aluminum 4 mm
Recorded temperature
vs. time
Alkoxysilane primer
(CNTs-filled) silicone
~2-4 mm
~ 1100C
>60 kW/m2
Adaptation of ISO 2685 test
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Flame-resistance testing : coating thickness ~2 mm (readily applied by brush painting)
Exceptional resistance to fire !
0
50
100
150
200
250
300
350
0 10 20 30 40 50 60 70 80 90
Time (min)
Tem
pera
ture
(C
)
0,1% CN7500 (1100C)
0,25 % CN7500 (1100C)
Non coated Aluminum
Unfilled Silicone
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Why such a flame barrier behavior ?
Fine CNTs dispersion and interconnectivity within cross-linked silicone
- Better dissipation of heat flow all over the coated surface - Higher char cohesion and
mechanical performances
NANOCYL (Belgium) : THERMOCYL Grade
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Protection of PU foams :
Without THERMOCYL :
Burns quickly with dripping
With THERMOCYL :
No burning (even after few minutes)
Courtesy from Nanocyl
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Biofouling of a ship hull by barnacles (photo courtesy International Paint Ltd)
Silicone Carbon Nanotube Nanocomposites :
anti-biofouling properties ?
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Biofouling : economic and environmental costs
Just for shipping : Biofouling causes increase in frictional drag on ships >>>>> Antifouling estimated annual
savings of 20 billion! (~ 120 million tons fuel/year) >>>>> Antifouling estimated annual CO2
reduction : 384 million tons CO2
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Biofouling is the accumulation of unwanted microorganisms, plants and animals on man-made surfaces-
such as those exposed to the marine environment - Fouling has been controlled traditionally by antifouling paints that contain biocides (i.e. compounds that are toxic to the organisms; tin or copper-based biocides). - But, regulations now require that antifouling paints must not cause adverse effects in the environment and the search is on for more environmentally friendly ways of deterring marine life from hitching a ride on the hull of a vessel
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As checked at two levels : - Lab scale : on Alga Ulva spores, barnacles (cyprids) - field tests : immersion in sea water (on the raft)
* Coll. with University of Birminghan, University of Newcastle and TNO
(AMBIO Project; 6th FP of EU)
CNT-filled silicone coatings : Anti-biofouling behavior
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Carbon nanotube-filled PDMS coatings
After 4 months of field trials
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Barnacle evaluation: 24h settlement assays with Barnacle Cyprids. Effect of MWNTs relative content
0
20
40
60
80
100
120
140
160
Glass UnfilledPDMS
0.05 wt %,MWCNTs
0.3 wt %,MWCNTs
0.5 wt %,MWCNTs
1 wt %,MWCNTs
2.5 wt %,MWCNTs m
ean
perc
en
tag
e s
ett
lem
en
t co
mp
are
d t
o t
he g
lass
st
an
dard
(%
)
Srie1
Equivocal pass line Outright pass line
Important effect of CNTs on the settlement behavior, even well under the already performant
(unfilled) silicone
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Removal* of AlgaUlva spores from MWCNTs-based coatings (*by exposure to a 52 Pa wall shear stress in a water-channel apparatus)
A. Beigbeder et al., J. Nanosci. Nanotechnol., 10, 2972(2010)
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Surface characterisation of CNTs- filled PDMS Atomic Force Microscopy
AFM images of (A) unfilled PDMS and (B) coatings filled with 0.1 wt% CNTs after one day immersion in water.
Upon MWNTs addition and after immersion in water, the flat surface is transformed into a nanostructured surface and consequently accounts
for the recorded enhancement in terms of fouling release properties.
B Z = 20 nm Z = 30 nm Z = 30 nm
(A) unfilled PDMS (B) PDMS filled with 0.1 wt% CNTs
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3D AFM topographic profiles of MWCNT-filled silicone coatings - after 1 and 6 days of immersion (a &,b) as observed in air, - and after 6 days of immersion (c) as observed directly in water
Nanostructuration of the coatings upon immersion in water.
0.1 wt% MWCNTS
1 day 6 days 6 days
Observations in air Obs. in water
A. Beigbeder et al., J. Nanostruct. Polym. Nanocomp. 5/2, 37 (2009)
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Carbon nanotube-filled PDMS coatings
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Carbon nanotube-filled PDMS coatings Biocyl/Liocyl TopCoat on Nadine super-tanker :
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Carbon nanotube-reinforced PDMS Conclusions : Possibility to strongly improve rheological and processing/applicability properties
high interfacial affinity >>> fine MWNTs dispersion >>>> - low percolation threshold (~ < 0.2wt%) Fine tuning of both electrical and thermal properties without any change of the bulk properties.
Remarkable flame resistance behavior
Improve of the foul release properties against alga foulers and macrofoulers via a lotus-like effect (nanorugosity) ?
BIOCYL
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Acknowledgements
AMBIO partners Pr. Callows group, University of Birminghan (biological evaluations)
Pr. Clares group, University of Newcasttle (biological evaluations)
TNO (biological evaluations)
BASF (AFM in sea water and dynamic contact angles)
Nanocyl (MWCNTs supplier) : F. LUIZI, M. CLAES, D. BONDUEL
UMONS-CIRMAP Alexandre BEIGBEDER
Philippe DEGEE
Rosica MINCHEVA
Myriam DEVALKENAERE
Joao BOMFIM
UMONS-CIRMAP (dynamic molecular simulation) Mathieu LINARES
David BELJONNE
Roberto LAZZARONI
European Framework Program
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Thank you for your attention !
Slide Number 1Slide Number 2Slide Number 3Slide Number 4Slide Number 5Slide Number 6Slide Number 7Slide Number 8Production of nanofiller-modified silicone systemsSlide Number 10Slide Number 11Slide Number 12Remarkable affinity between MWNTs and PDMSSlide Number 14Slide Number 15Slide Number 16CNT-filled Silicone : FIRE RESISTANCE BEHAVIORFlame-resistance testingFlame-resistance testing : coating thickness ~2 mm (readily applied by brush painting)Why such a flame barrier behavior ?Slide Number 21Slide Number 22Biofouling : economic and environmental costsSlide Number 24CNT-filled silicone coatings : Anti-biofouling behaviorSlide Number 26Slide Number 27Slide Number 28Slide Number 29Slide Number 30Slide Number 31Slide Number 32Slide Number 33Slide Number 34Slide Number 35