Dielectric and dynamic mechanical studies on homogeneous PBA/PBMA interpenetrating polymer networks

Broadband dielectric relaxation spectroscopy (DRS, 10−2‐109 Hz), thermally stimulated depolarization currents (TSDC) techniques and dynamic mechanical analysis (DMA) were employed to investigate the dynamic glass transition and, thus, phase morphology in sequential IPNs of poly(butyl acrylate) (PBA) and poly(butyl methacrylate) (PBMA) with 10 weight % of ethyleneglycol dimethacrylate (EGDMA) as branching agent. In a parallel investigation, similar IPNs with only 0.1% branching agent showed clearly phase separation. In the highly branched IPNs, forced compatibilization induces miscibility of the two components. The results are discussed in terms of suppression of cooperativity and dynamic heterogeneity in the IPNs.