Reactive Extrusion of Polyester Elastomers

摘要

Recently, cyclic oligomers of Polybutylene Terephthalate (cPBT) have been commercially introduced. cPBT is a mixture of 2 to 6 repeating units of PBT, a well known engineering thermoplastic. The mixture melts from 160C to 195C. Since there are no polymer chains to entangle, the melt viscosity is very low, ranging from 20 to 50 centipoises. With the addition of heat and a catalyst, the oligomer rings open and undergo a polymerization reaction which does not generate either an exotherm or volatile gases. This combination of features opens the door to new approaches for reinforced composites and for reactive compounding extrusion.