Synthesis and Characterization of Allyl- Functional Polycarbonates and Polycarbonate/Polysiloxane Block Copolymers

摘要

Bisphenol-A-based polycarbonate (PC) is generally recognized as the most impact resistant, transparent engineering thermoplastic available. While PC exhibits exceptionally good impact strength for an engineering thermoplastic, it has a tendency to undergo brittle failure in notched impact tests. While rubber toughening of PC by melt blending rubber particles into the PC can significantly increase impact properties, the particles generally scatter visible light resulting in opaque materials. To overcome this deficiency, block copolymer structures have been investigated in which rubbery polymer segments are incorporated directly into the PC backbone to limit rubber domain size and produce transparent materials. Polycarbonate/polysiloxane (PC-PSiO) multiblocks copolymers have been previously reported where PSiO blocks form the rubbery domains. The majority of the synthesis strategies for PC-PSiO multiblock copolymers involve the reaction of a polydimethylsiloxane (PDMS) modified with nucleophilic end-groups with BPA and phosgene. As a result of the synthesis method, the resulting copolymers possess polydisperse block lengths which affect their optical and mechanical properties.