COMPATIBILIZING EFFECT IN INTERPENETRATING POLYMER NETWORKS

alpha,omega-Acrylate terminated poly(1,3-dioxolane) (polyDXL) was copolymerized with methyl acrylate and methyl methacrylate for the synthesis of block copolymer networks. It was shown by dynamic mechanical thermal analysis (DMTA) that the presence of covalent bonds between polyDXL and the polyacrylate leads to a high degree of compatibility. In contrast, the combination of the same two components in network form, leading to sequential interpenetrating polymer networks (IPN's), resulted in phase-separated materials. When the above-mentioned block copolymer structures, in which one of the blocks is chemically identical to the polyacrylate used in the second network, were applied in the first network of the IPN, an increase of miscibility between the two types of polymers was observed. DMTA analysis revealed that the morphology of these IPN's could be varied from phase-separated to homogeneous materials by increasing the polyacrylate fraction in the first block copolymer network. The possibility to degrade the polyDXL segments in an acid environment allows the complete degradation and extraction of one network in the IPN's and hence provided an interesting approach to the study of domain characteristics by optical microscopy.