| Abstract: | A series of polyurethane-poly(ethyl acrylate) interpenetrating networks (IPNs) containing 40 wt% polyurethane were prepared, in which the cross-link density of the polyurethane component was varied by altering the ratio of diol/triol. Decreasing the molecular weight between crosslinks from 9500 to 1200 g/mol brought about an increase in the tensile strength accompanied by a decrease in elongation at break. The tensile properties of the IPNs are, however, poorer than those of the equivalent polyurethane homopolymers. Electron microscopy showed that the polyurethane was present as distinct phases, connected by a cellular fine structure, in the poly(ethyl acrylate) matrix. Dynamic mechanical analysis as well as sonic velocity studies gave results which were consistent with this morphological picture. |
