The microstructure and fracture performance of styrene–butadiene–methylmethacrylate block copolymer-modified epoxy polymers

• DOI: 10.1007/s10853-013-7481-8
• Publication Date: 2013-06-10T15:38:28Z
• Authors: H. M. Chong; A. C. Taylor
• Keywords: Materials Science(all); Mechanics of Materials; Mechanical Engineering; 02 engineering and technology; 0210 nano-technology; 620

The microstructure and fracture performance of an anhydride-cured epoxy polymer modified with two poly(styrene)-b-1,4-poly(butadiene)-b-poly(methyl methacrylate) (SBM) block copolymers were investigated in bulk form, when used as the matrix material carbon fibre reinforced composites. 'E21' SBM copolymer has a higher butadiene content molecular weight than 'E41'. A network aggregated spherical micelles was observed for E21 epoxy, which became increasingly interconnected increased. steady increase energy measured increasing content, from 96 to 511 J/m2 15 wt% E21. Well-dispersed 'raspberry'-like particles, sphere-on-sphere morphology poly(styrene) core covered poly(butadiene) obtained loadings up 7.5 E41 SBM. This changed partially phase-inverted structure at contents, accompanied by significant jump 1032 E41. glass transition temperatures remained unchanged addition SBM, indicating complete phase separation. Electron microscopy cross polarised transmission optical revealed localised shear band yielding, debonding void growth main toughening mechanisms. Significant improvements not composites, poor toughness transfer composite. bridging unmodified reduced due better fibre–matrix adhesion. size crack tip deformation zone composites restricted fibres, hence reducing compared toughest materials.