Polymer, Vol.40, No.17, 4769-4775, 1999
Modulated-temperature differential scanning calorimetry: 15. Crosslinking in polyurethane-poly(ethyl methacrylate) interpenetrating polymer networks
The glass transition behaviour and morphology of 70:30 polyurethane-poly(ethyl methacrylate) (PU-PEMA) interpenetrating polymer networks (IPNs) in which the crosslink density in both networks was systematically varied were investigated by means of modulated-temperature differential scanning calorimetry (M-TDSC) and dynamic mechanical thermal analysis (DMTA). The observed influence on the glass transition temperature, T-g, was similar for both the M-TDSC and DMTA studies, but some substantial differences also existed. MTDSC was more sensitive to phase separation than DMTA. On increasing the crosslink density in the first-formed PU network, the weight fraction of the interphase component increased. Higher crosslinking levels in the PEMA network had relatively little influence.
Keywords:LATEX-PARTICLES;MORPHOLOGY