Design of Porous Polymeric Materials from Interpenetrating Polymer Networks(IPNs):Poly(DL-lactide)/Poly(methyl methacrylate)-Based Semi-IPN Systems

摘要

Oligoester-containing semiinterpenetrating polymer networks(semi-IPNs)can be effectively used as precursors for the generation of(meso)porous networks with tunable pore sizes.In a first step,novel poly(DL-lactide)(PLA)/poly(methyl methacrylate)(PMMA)-based semi-IPNs were prepared by varying two structural parameters,namely the cross-link density of PMMA subnetwork(initial MMA/ dimethacrylate composition ranging from 99/1 to 90/10 mol %)and the cross-linker nature(bisphenol A dimethacrylate,diurethane dimethacrylate).The kinetics of the free-radical cross-linking process was monitored by real-time near-infrared spectroscopy.In a second step,the extraction of the un-cross-linked oligoester subchains from the semi-IPNs was investigated.The possibilities afforded by this straightforward and versatile route to(meso)porous polymeric materials were discussed,and the porosity of the resulting methacrylic networks was examined by scanning electron microscopy(SEM)and thermoporom-etry using differential scanning calorimetry(DSC).The dependence of pore sizes and pore size distributions on the cross-linker content and nature could be related to turbidity measurements of semi-IPN precursors and explained in terms of polymer-polymer miscibility through the evaluation of PLA/PMMA interaction parameters.