"Epoxy-matrices have high modulus, strength, excellent creep resistance, but lacks ductility. One approach to improve the mechanical toughness is the addition of thermoplastic elastomers (TPEs). The TPEs investigated here are triblock copolymers of styrene-butadiene-methyl methacrylate (SBM) and methylmethacrylate-butylacrylate-methylmethacrylate (MAM) of the ABC and ABA type, respectively. The effect of concentration (1-12.5 wt %) of these TPEs on a diglycidyl ether of bisphenol-A (DGEBA) epoxy cured with metaphenylenediamine (mPDA), has been investigated. The TPE-DGEBA epoxies were characterized by TGA, DMA, SEM and impact. The flexural modulus, flexural strength and thermal resistance remained unaffected up to 5 wt% loading of TPEs, and exhibited less than 10% decrease at higher weight percent. Tg was unaffected for all concentrations. Fracture toughness was improved 2503030% and up to 3703035% (when non- stoichiometric amount of curing agent was used) with TPE addition to epoxy/mPDA matrix. A SBM(1phr)EPON system was chosen to be the matrix of choice for a fiber reinforced composite system with a 4wt% aromatic epoxy sizing on a AS4 (UV-treated) carbon fiber. The 01D3C and 901D3C flexural modulus and strength of a SBM modified system was compared with the neat and their fracture surfaces were analyzed. A 89% increase in flexural strength was observed in a 901D3C flexural test for the modified system when compared with the neat. Novel sizing agents were also developed to enhance interfacial shear strength (IFSS) and the fiber-matrix adhesion and their birefringence pattern were analyzed."--Page ii.
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