Compatibilizing and foaming of PC/PMMA composites with nano-cellular structures in the presence of transesterification catalyst

Compatibility of polycarbonate (PC) and poly methyl methacrylate (PMMA) alloys was improved by using a transesterification catalyst (Sn[Cl.sub.2]- 2[H.sub.2]O). Modified PC/PMMA alloys exhibit single [T.sub.g], and their initial island phase existing in the SEM were transformed into uniform surface. Besides, the transmittance of the modified alloys was increased from original 40% to 85%. Moreover, PC/PMMA alloys and PC foams with micro-cellular and nano-cellular structures were prepared by solid-state C[O.sub.2] foaming in the presence of transesterification catalyst. Distinctively, there are obvious nano-cellular structures existing in the PC samples, but no related nanostructures were found in PMMA samples, after treated by same amount of catalyst and foaming process for pure PC and PMMA matrix. Furthermore, the effects of foaming temperature and segment structure on their foaming behavior were also studied. Additionally, a uniaxial stress experiment was conducted at a specific temperature to simulate the biaxial stress during the foaming process for discovering the mechanism of nanopore formation. Therefore, the concept of nano-ccllular structures will point out a direction for the development of high-performance, heat insulation PC materials of the next generation.