ICAR ATRP of Acrylonitrile under Ambient and High Pressure.

It is well known that well-defined polyacrylonitrile (PAN) with high molecular weight (Mw > 106 g·mol-1) is an excellent precursor for high performance carbon fiber. In this work, a strategy for initiators for a continuous activator regeneration atom transfer radical polymerization (ICAR ATRP) system for acrylonitrile (AN) was firstly established by using CuCl₂·2H₂O as the catalyst and 2,2'-azobis(2-methylpropionitrile) (AIBN) as the thermal initiator in the presence of ppm level catalyst under ambient and high pressure (5 kbar). The effect of catalyst concentration and polymerization temperature on the polymerization behaviors was investigated. It is important that PAN with ultrahigh viscosity and average molecular weight (Mη = 1,034,500 g·mol-1) could be synthesized within 2 h under high pressure.