The effect of oligomer blending on the flow properties of polycarbonate

Abstract

We successfully prepared high-flow polycarbonate (PC) by blending commercial PC with a low molecular weight PC oligomer. The oligomer was synthesized by the addition of a large quantity of mono functional phenol groups, and the chain end group was reacted with p-tertiary butyl phenol (PTBP) to block the reactivity. The viscosity average molecular weight (M v ) for the oligomer was about 4,000-5,000 g/mol, compared to ~19,000 g/mol for the PC blend obtained by blending 10 wt% of the prepared oligomer with the commercial grade PC (M v of 21,000 g/mol). The blended PC had a melt flow index of 45, which is 2.5 times higher, and a processing temperature that was 20 o C lower, than that of commercial grade PC having a similar M v .

Chemical modification of bisphenol a polycarbonate by reactive blending with ethylene carbonate

“…Indeed, a lower T g leads to a melt viscosity reduction and therefore to a better processing of the material. Other routes to prepare PC grades with improved melt flow properties have been reported in the literature; for example, blending PC with oligomers or other polymers such as acrylonitrile butadiene styrene (ABS), polyesters, or polydimethylsiloxane yields polymer blends with better flow and processing properties. However, the resulting materials are not completely transparent, thus preventing their use in applications that demand light transmission or clarity…”