Synthesis and characterization of polymer networks based on two kinds of macromonomer

Abstract

pH-sensitive networks were obtained by radical copolymerization of telechelic poly(1,3-dioxolane) (PDXL) with acrylic acid (AA). The PDXL bismacromonomer was synthesized by two methods: one (PDXLDA) by acrylation of the corresponding dihydroxylated PDXL with AA in pyridine; the other (PDXLHM) by adding 2-hydroxyethylmethacrylate as a transfer agent during the cationic polymerization of 1,3-dioxolane (DXL). The copolymer networks of poly(AA-b1-DXL) and poly(AA-b2-DXL) prepared by PDXLDA and PDXLHM macromonomers with AA, respectively, have very different physical properties. Poly(AA-b1-DXL) networks are pH-sensitive, while poly(AA-b2-DXL) ones are not. The poly(AA-b1-DXL) networks degrade easily under acidic condition, while poly(AA-b2-DXL) ones do not. The great differences between the properties of the networks depend on the network structure, which is directly related to the corresponding bismacromonomer structure. Microphase separation in all the networks can be observed by scanning electron microscopy. The network structure, swelling behavior and degradation were characterized by Fourier transform IR spectroscopy, differential scanning calorimetry, scanning electron microscopy and swelling data.