This study investigated toughening epoxy coatings by adding a block copolymer called PEP-PEO at 5 wt%. The copolymer was hypothesized to self-assemble into structures that prevent crack propagation, improving coating toughness and durability. Coatings were produced with varying copolymer morphology by adjusting processing. Mechanical properties testing showed coatings with mixtures of spherical and worm-like micelles had significantly improved abrasion resistance compared to the neat epoxy, with no reduction in modulus or glass transition temperature. TEM imaging confirmed the micelle morphology was tunable but did not segregate within the coating thickness.

1. Microstructure and Mechanical Properties of
Block Copolymer Modified Epoxy Resins
Authors: Monique E. Cook, Tuoqi Li, Dr. Frank Bates
Home Institution: Florida A&M University
Summer Sponsor: UMN MRSEC
From hardwood floor finishing to food packaging, epoxy coatings are widely used today to extend the life of
materials that would otherwise be susceptible to deterioration (i.e. corrosion). This investigation takes a
closer look into toughening epoxy coatings by the inclusion of block polymers at a low weight percentage (5
wt %) with the hope of creating a more durable coating. The epoxy resin being studied contains a
commercially available epoxy monomer (Epon 828) and a curing agent (C541). When added to the resin,
poly(ethylene-alt-propylene)-b-poly(ethylene oxide) (PEP–PEO), the block polymer, will self-assemble into
various structures that will toughen the coating by preventing the propagation of cracks. By varying the
morphology of PEP-PEO in the resin, tougher coatings can be prepared. Mechanical properties, which are
dependent on the thickness of the coating and the morphology of the block polymer, will be determined by
various techniques. It has been hypothesized that a worm-like structure would be the most beneficial while
still maintaining the integrity of the original resin; that is to say, that the modulus and glass transition
temperature will not be sacrificed.
Long-lasting
Flexible
Good Adhesion
Transparent
Abrasion Resistant
Tough
Abstract
I. Background
What makes a good coating?
IV. Results & Conclusions
II. Materials
Block Polymer “Hardener” Epoxy Monomer
PEP-PEO C541
DMP 30
Epon 828
Resin
Micelle Shape: controlled by
p and q
Concentration in resin: 5 wt%
Casting Solvent
Toluene
curing agent
accelerator
III. Method
Rod Coating
Sol'n Conc. (wt%) 10, 20, 30
Substrate *PET
Critical Parameters Wire-Wound Rod: #0
Curing Temp. 60°C
Thickness ~10 µm
*Polyethylene terephthalate, donated by 3M
> Wear Resistance (Abrasion Test)
> Adhesion (Fragmentation)
> Distriubution (TEM)
> Morphology (TEM)
> Glass Transition Temp. (DSC)
Prepare Sample
Solution
• 30 wt% in Toluene
Coat Substrate
• Wire Wound Rod: #0
Cure
• 60°C for 8 hrs.
Measure Thickness
Cut and Scratch
• 460x
Plot and Analyze
• Abrasion Cycles vs.
Intensity (% T)
• Transmission Electron
Microscopy (TEM)
Spin Coating
Sol'n Conc. (wt%) 10
Substrate Silicon Wafer
Critical Parameters 3000 RPM, 40s
Curing Temp. 60°C
Thickness ~100 nm
Prepare Sample
Solution
• 10 wt% in Toluene
Substrate
• Clean: Plasma Treated
Cure
• 60°C for 8 hrs.
Analyze
• Transmission Electron
Microscopy (TEM)
0.0
20.0
40.0
60.0
80.0
100.0
120.0
10 40 70 100 130 160 190 220 280 340 400 460
RelativeIntensity(%T)
Abrasion Cycles
Wear Resistance
Neat
EB12-34
EB15-49
EB17-54
Acknowledgements
> Tuoqi Li > Dr. Frank Bates > Dr. Lorraine Francis > Dr. Nelly Mateeva
This work was supported primarily by the National Science Foundation MRSEC and
REU programs under Award Numbers DMR-1263062 & DMR-0819885
Toughening Strategies for Bulk Epoxy Thermoset
Block Copolymers as Toughening Agents
 Low loadings ( ~ 5 wt.%)
 Significant toughening effects
Advantages:
 Epoxy-philic & epoxy-phobic block(s) thermodynamically driven
self-assembly
Micelle Morphology
EB17-54 (5 wt.%) Thickness = ~ 10 μm
Coating/air free surface Bulk portion Coating/PET interface
sphere
EB15-49 (5 wt.%) Thickness = ~ 10 μm
Coating/air free surface Bulk portion Coating/PET interfaceworm
sphere
EB12-34 (5 wt.%) Thickness = ~ 10 μm
Coating/air free surface Bulk portion Coating/PET interface
sphere
worm
 Not much reduction in E and Tg
 Morphology tunable
• Block Copolymer Morphology (TEM) by Rod Casting
• Abrasive Wear Resistance Results
1. Mixture of spherical & worm-like micelles (EB12-34 & 15-49) and spherical micelles (EB17-54)
2. No micelle segregation to the interface or free surface
1. Significantly improved abrasive wear resistance at as low as 5 wt % of modifiers loading
2. A great improvement in the coating fracture toughness
• Block Copolymer Morphology (TEM) by Spin Coating
EB12-34 (5 wt.%) Thickness = ~ 500 nm
1. Mixture of spherical & worm-like micelles
2. No micelle segregation to the interface or free surface
3. Thickness doesn’t effect the micelle morphology or
distribution