Fracture of polymer blends: Effect of characteristic number of interfacial entanglements and matrix toughness

Fracture behavior of polymer blends with variable miscibility and matrix toughness was investigated using partially annealed films of sintered poly (styrene-co-acrylonitrile) and poly (methyl methacrylate-co-butyl acrylate) nanoparticle mixtures with uniform distributions, asymmetric polyinterface systems, to elucidate the whole interpenetration spectrum. The effect of copolymers composition distribution on their interdiffusion was also modeled to achieve precise interpenetration depths. Normalized specific wear energy to the matrix toughness correlated the characteristic number of interfacial entanglements/degree of segregation with three distinct regimes: weak and transition ones with slopes of 0.33 and 2 complementing the strong regime with system dependent slope. Polymer blends fracture in the weak and transition regimes corresponds their governing micro-mechanisms: chain pullout and mixed pullout/scission, respectively. Slope system dependency in long annealed strong regime appears due to the components intrinsic stiffness disparity. Molecular weight distribution also causes a none-zero slope for strength build up of symmetric systems in the third regime.