Effect of dicarboxy terminated polystyrene strengthening immiscible polystyrene poly(methyl methacrylate) interface

The fracture toughness between polystyrene (PS)/ poly(methyl methacrylate) (PMMA) reinforced with reactive polymers, poly(glycidyl methacrylate) (PGMA ) and dicarboxy or monocarboxy terminated PS (dcPS and mcPS), was measured by the asymmetric fracture test. Molecular weight effect of mcPS, although the molecular weight distribution is rather polydisperse, on the maximum ac hievable fracture toughness, G(max) qualitatively agreed with the results o f the monodisperse case(4,5)). In the case of dcPS with M-w congruent to 14 2 K, G(max) reached ca. 170 J/m(2) which is nearly 8 times higher than that of mcPS of molecular weight of about 150K. From the mechanical point of vi ew, dcPS with a degree of polymerization (N) greater than the ratio of chai n breaking force to monomeric friction force (f(b)/f(mono)) is more effecti ve in enhancing the interfacial adhesion than mcPS since it provides two st itches to the interface. It was also shown by Monte Carlo simulation on rea ctive polymer system that the di-endfunctional polymers are more effective than mono-endfunctional polymers in reinforcing the week interface between immiscible polymers.