NanoCentral: Collaboration through the nanomaterials value chain · 2010. 10. 6. · Sample 44...
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NanoCentral: Collaboration through the nanomaterials value chain Allen Reid NanoMaterials09 17-18 th June 2009, Bonn
Transcript of NanoCentral: Collaboration through the nanomaterials value chain · 2010. 10. 6. · Sample 44...
NanoCentral: Collaboration through the nanomaterials value chain
Allen Reid NanoMaterials09 17-18th June 2009, Bonn
• Development of optically transparent coated plastic films containing nano ZnO with enhanced durability for outdoor applications
– Development of R&D grades of nano ZnO and comparison to commercially available material
– Optimisation of dispersion process– Preparation and evaluation of coated films
Nano ZnO Case Study
MSG
NanoCentral Case Study Nano
ZnO
in coated plastic films
Nano ZnO Preparation(range of properties)
Johnson Matthey Intrinsiq Materials
Commercial ZnOSamples
Disperse in acrylate(optimise)
Lubrizol Primary Dispersions
University of Liverpool
Formulate and apply acrylate coatingson plastic films
MacDermid Autotype
• Characterise physical and chemical properties of powders and simple dispersions (TEM, Gas Ads, PSD, XRD)
•Compare R&D and Commercial samples
Johnson Matthey Intrinsiq MaterialsIntertek MSG
• Characterise quality of dispersions (PSD, TEM, XRD, Stability)
•Compare R&D and Commercial ZnO samples
LubrizolUoLIntertek MSG
• Evaluate performance of coated films (durability, UV screening, physical and mechanical properties)
•Compare R&D and Commercial ZnO samples
MacDermid AutotypeIntertek MSG
Production
Characterisation & Evaluation
NanoCentral Case Study Nano
ZnO
in coated plastic films
Nano ZnO Preparation(range of properties)
Johnson Matthey Intrinsiq Materials
Commercial ZnOSample
Disperse in acrylate(optimise)
LubrizolPrimary Dispersions
University of Liverpool
Formulate and apply acrylate coatingson plastic films
MacDermid Autotype
• Characterise physical and chemical properties of powders and simple dispersions (TEM, Gas Ads, PSD, XRD)
•Compare R&D and Commercial samples
Johnson Matthey Intrinsiq MaterialsIntertek MSG
• Characterise quality of dispersions (PSD, TEM, XRD, Stability)
•Compare R&D and Commercial ZnO samples
LubrizolUoLIntertek MSG
• Evaluate performance of coated films (durability, UV screening, physical and mechanical properties)
•Compare R&D and Commercial ZnO samples
MacDermid AutotypeIntertek MSG
Production
Characterisation & Evaluation
Commercial Nano ZnO
• Supplied in powder form
• High purity un-coated ZnO
• Manufactured by flame spray pyrolysis process
• Typical surface area 20m2/g
• Equivalent to ~55 nm primary particle size
Nano ZnO Case Study
Lubrizol Advanced Materials Dispersion
Products•
A product range of over 60 different dispersant systems
•
Solsperse, Solplus, Ircosperse, Colorburst
Process•
Application development labs covering coatings, inks and plastics
•
Latest nano bead mills•
Twin screw extruders
Facility•
Provide services to NanoCentral on a commercial basis
•
Located at Blackley, Manchester
Polymer with terminalfunctional groups
Lubrizol Advanced Materials Dispersion
•
Select potentially suitable dispersants based on particle and carrier chemistry•
Solplus D530, AX5•
Solsperse 28000, 35000, 39000, 71000
•
Determine optimum milling conditions (WAB RL, 0.1mm ZrO Yi beads) using one dispersant from above (Solplus D530)•
Visc=0.5Pas, 3000rpm, Tip speed 7.75m/s
Zinc Oxide 645.92 Solplus D530 129.18 HDDA 516.74 TOTAL 1291.84 Initial Millbase Viscosity - % Pigment 50.00 % AOWP 20.00
Lubrizol Advanced Materials Dispersion
•
Test viscosity profiles for all potential dispersants and select best three•
Solsperse 28000 (lower polarity polyester comb-type with amine anchor)
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Solsperse 71000 (higher polarity polyester comb-type with amine anchor)
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Solplus AX5 (acidic anchor alkoxylate chain)
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Optimise formulations with Scandex / glass bead pre-screen milling process
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Prepare final formulations on WAB RL mill
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All dispersions have average particle size <100nm and excellent stability
%Formulations used in WAB Sample Number 44 56 58 Zinc Oxide 40.43 44.00 46.41 Solsperse 71000 (HPA 56B) - 8.80 - Solsperse 28000 9.36 - - Solplus AX5 - - 10.72 HDDA 50.21 47.20 42.87 TOTAL 100.00 100.00 100.00 Initial Millbase Viscosity 0.530 0.701 1.429 % Pigment 40.43 44.00 46.41 % AOWP 23.15 20.00 23.10
Details of agitator mill Type WAB RL mill Mode of operation Re-Circu lation Screen 0.025 Grinding chamber design Silicon nitride Rotor design Zirconium Yi Feed pump Helical Rotational speed (rpm) 3000 Tip speed (m/s) 7.75 Temperature (°C) 26± 2 Premix Volume (ml) 100 Milling time (hrs) 10 Details of grinding media Type ZrO Yi Diameter[mm] 0.10 Grinding media density[kg/m^3] 6.3 Grinding media bulk density[kg/m^3] 3.78 Volume[cc] 55.7 Grinding chamber filling degree[%] 70.0
Laser Diffraction PSD (nm) (by vol)Sample D50 D90
44 72 125
56 64 115
58 80 133
MacDermid Autotype Coated Film Production
Products•
Coated Plastic Films•
Displays, Solar Energy, Diagnostics•
In automotive, hard coated switches for Mercedes
Process•
Coat UV cure solvent-free formulations, typically 3-30 microns thick onto polyester, polycarbonate and PMMA films
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Gloss, textured, or structured surface with customised properties
•
Pilot facilities available
Facility•
Provide services to NanoCentral on a commercial basis
•
Located at Wantage, Oxon
MacDermid Autotype Coated Film Production
Film Production•
Three samples of ZnO dispersion in HDDA received from Lubrizol
•
A series of model coating formulations prepared containing:
•
HDDA•
Urethane acrylate oligomer•
Photoinitiator•
ZnO dispersions
•
Formulations were coated onto PET and UV cured using Autotype process
•
Final films were approximately 5 microns thick containing ZnO at approximately 6, 16 and 30% (wt)
MacDermid Autotype Coated Film Production
Testing•
Coated film samples subjected to environmental testing•
Condensation & UV ageing on Atlas UVCON
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Arid UV Exposure on Heraeus sunlight tester
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Haze measurements (Byk Gardner Haze-Gard Plus)
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Transmission measurements (Byk Gardner Haze-Gard Plus)
•
Yellowing (X-Rite SP68 spectrophotometer, E313 & D1925 standards)
MacDermid Autotype Coated Film Production
Results•
Sample 44 (Solsperse 28000) rejected due to formulation instability problems when mixed with acrylate oligomer
•
The 6% ZnO films had good optical properties. The 16% and 30% ZnO films were slightly hazy to the naked eye
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ZnO addition improved adhesion performance on ageing, although 30% ZnO required for improvement in pure sunlight testing adhesion
•
6% and 16% ZnO films showed no negative impact on abrasion resistance. 30% ZnO films compromised abrasion resistance
•
ZnO addition increases haze when subjected to environmental testing. Sample 58 (Solplus AX5) not as bad as sample 56 (Solsperse 71000)
Conclusions•
Some positives but further work required•
Smaller particle size ZnO dispersions required for better optical properties•
Co-formulation with organic UV absorbers and stabilisers may be required to optimise weathering performance
•
Other formulation changes may improve abrasion resistance
Intertek MSG CharacterisationParticle Size Determination•
PCCS•
Disc Centrifuge•
Laser Diffraction
Processing of Polymer Nano-composites•
Effect of filler loading on processability•
Effect of processing on filler distribution•
Optimum processing conditions
Facility•
Publicly Funded – Open Access•
Located at Wilton Centre•
Wide range of supporting techniques, e.g. TEM, XRD, surface analysis
MSG
Victory 40
Intertek MSG Characterisation•
Received samples of ZnO powder raw material, ZnO dispersions from Lubrizol and samples of coated films containing ZnO from MacDermid
•
Analysis of ZnO powder•
BET surface area and pore size analysis•
XRD
•
Analysis of ZnO dispersions•
TEM•
XRD •
Particle size distribution•
PCCS•
CPS Disc Centrifuge•
Image Analysis (TEM images)
•
Analysis of ZnO containing films•
TEM, EDX, CBED•
XRD•
UV-Vis spectroscopy
MSG
Intertek MSG Particle Size DistributionPhoton Cross Correlation Spectroscopy (PCCS) on diluted dispersions•
Reproducible data obtained•
Dispersions very stable to dilution (required for analysis)•
Mean diameters by volume•
44 – 75.2nm•
56 – 73.0nm•
58 – 90.6nm•
PCCS measures hydrodynamic diameter, which will include a contribution from particle and dispersant. The larger size of sample 58 compared to samples 56 and 44 is consistent with differences in the nature of the dispersants
MSG
0
1
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Cor
rela
tion
/ %
0.0001 0.0005 0.0010 0.005 0.010 0.05 0.10 0.5 1.0 5 10 50Lag time / ms
Correlation curves for ZnO in HDDA - 58Runs that make up Integral 110Mean - 92.5 nm
Intertek MSG Particle Size Distribution
•
Reproducible data obtained•
Smaller values obtained compared to PCCS
•
Mean diameters by volume•
44 – 58.9nm•
56 – 56.8nm•
58 – 55.7nm•
Calculated mean diameter by number•
44 – 38.8nm•
56 – 37.5nm•
58 – 34.9nm•
DC measures Stokes diameter, which in this case is smaller than the hydrodynamic diameter measured by PCCS, and is relatively consistent across all three samples
MSG
Disc Centrifuge analysis of diluted dispersions
Intertek MSG TEM on dried Dispersions
MSG
• 3 crystalline particle types detected
– ZnO nano-particles– Larger ZnO platelets– Rods (organic, not ZnO)
44 – 45.9 nm 56 – 35.3 nm 58 – 34.8 nm
Image Analysis Diameter Distribution (nm)
0
5
10
15
20
25
30
0 20 40 60 80 100 120
Diameter (DCircle - nm)
% C
ount 44
56580.2 µm
More clusters
Nano
ZnO
Case Study Comparison of all PSD measurements
SampleLaser Diffraction (D50)Lubrizol
PCCSIntertek
Disc CentrifugeIntertek
44 72 75 5956 64 73 5758 80 91 56
SampleLaser Diffraction (D50)Lubrizol
TEMIntertek
Disc CentrifugeIntertek
44 33 46 3956 34 35 3858 41 35 35
Mean Volume Distributions (nm)
Mean Number Distributions (nm)
Good correlation
Intertek MSG TEM on cross-sections of 30% ZnO
film
MSG
0.5 µm
56
• Generally well dispersed• Decoration of interfaces by ZnO• Some pullout at section faces
– equal numbers to those left in?
PET film
0.2 µm
PET film
58
Some chains of ZnO particles
Intertek MSG TEM – Platelet composition and structure
MSG
PET film
• Platelets are ZnO• c-axis found in plane, normal to
plane, and possibly “randomly” oriented w.r.t. platelet
• “Random” crystallography believed to be a consequence of ZnO production process (currently under investigation)
Platelet composition: "58" film coating
0
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100
0 1 2 3 4 5 6 7 8 9 10
keV
Cou
nts
NanoCent/58F/A3 acicular or plateZn-L
O-K
Zn-Kα
Cu-Kα(Cu grid)
Zn-KβC-KCu-Kβ(Cu grid)
EDX
EDX and CBED performed at very low beam currents to avoid sample damage
(1010)_
(1010)_
(1120)_
(0000)
Near [0001] zone-axis in ZnO
Near [0001] zone-axis in ZnO
(1010)_
(1010)_ (1120)
_
(0000)
Convergent Beam Electron Diffraction
Intertek MSG TEM –
Summary
MSG
• ZnO particles of 2 types– Approximately equi-axed nano-particles - 10-50nm– Platelets from the skin on sprayed droplets - up to 200nm x 30nm
• In platelets, ZnO crystallography shows variable orientation
• Little ZnO aggregation in coatings (56 and 58)– Some chains of nanoparticles
• In coatings the particles sit in a partial monolayer at the interfaces with substrate and air
– Tendency for the platelets to be aligned parallel to the interface– Implications for adhesion to substrate?– Some scratch resistance imparted?
Intertek MSG XRD
MSG
Lin
(Cps
)
0
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Zinc Oxide – ZnOZincite structureHexagonal
40% ZnO thin film in HDDA
ZnO (dry powder)
scatter fromliquid
0 0.2 0.4 0.6 0.8 10
5 10 3−×
0.01selected peak dataWH fitIntercept
Williamson Hall Plot
sin (theta)
IB.c
os(th
eta)
0 0.2 0.4 0.6 0.8 10
7.5 10 3−×
0.015selected peak dataWH fitIntercept
Williamson Hall Plot
sin (theta)
IB.c
os(th
eta)
40% ZnO thin film in HDDA
crystallite size = 32 nm(from intercept)lattice distortion = 0.08%(from slope)
ZnO (dry powder)
crystallite size = 38 nm(from intercept)lattice distortion = 0.02%(from slope)
Microstructure of ZnO materials from XRD
wh ⎯ ≈ 1w
h
Approx. equiax crystallites with some lattice distortion
Intertek MSG UV-Vis Spectroscopy
MSG
Nano ZnO Case Study MSG
Conclusions• ZnO is well dispersed in both dispersions and
coated films• Particle size measurements using various
techniques correlate well and show mean particle sizes in the 30 – 90nm range
• Crystallite size correlates well with particle size• Particle size distributions need to be further
reduced to improve optical properties• Larger platelet morphology probably results in
major contribution to haze, and platelet alignment at interface may adversely affect adhesion
Further Work• Further refine the Lubrizol bead mill dispersion
process including using smaller beads to further reduce particle size distributions
• Incorporate R&D ZnO samples prepared by Johnson Matthey and Intrinsiq Materials
• Evaluate novel milling techniques as alternative to bead mill process (University of Liverpool, Primary Dispersions)
-5
15
35
55
75
95
100 200 300 400 500 600 700 800 900
wavelength (nm)
% T
[Zn] 0.25 mol/L
[Zn] 0.5 mol/L
[Zn] 0.75 mol/L
[Zn] 1 mol/L
Commercial ZnOnanopowder
Johnson Matthey R&D ZnO
Acknowledgments MSG
• Lubrizol– Gregory Brown, Ian Maxwell
• Autotype– Nigel Holmes, Steve Abbott
• Intertek– Bill Meredith, Mervyn Shannon, Steve Norvel, Ian Priestnall
• Johnson Matthey– Peter Bishop, Benedicte Thiebaut, Hanna Rajentie, Virginia
Buche, Graham Henderson
• Intrinsiq Materials– Ian Clark
• If you would like to benefit from collaborating through the nanomaterials value chain……
• If you would like to access the world-class facilities and expertise with the Nanocentral Alliance……
……….Then please contact us
NanoMaterials09 Exhibition Areawww.nanocentral.eu +44 (0) 1642 442 464
How to participate in NanoCentral
Key Contact Information
Stephen [email protected] 625 000
Allen ReidBusiness Development [email protected] 855 263
Dan GoodingBusiness Development [email protected] 772 497
Steve DevineOperations [email protected] 442 464
Helen ParsonsProject [email protected] 443 643
