High shear flow of short glass fibre filled polybutylene terephthalate - Part II: Developing a high rate injection rheometer

A high rate injection rheometer was developed to investigate the flow behav iour of polybutylene terephthalate (PBT) in the very conditions of injectio n moulding, it consists essentially of a barrel-and-die system fixed betwee n the platens of the injection machine. Suitable transducers and the approp riate acquisition system allow all necessary data to be obtained in order t o assess the entrance pressure loss and the true viscosity function. Filled PET exhibits a significant curvature of the flow curve; the entrance press ure loss is more than doubted. However, as observed with an IR camera, the extrudate swell is totally inhibited by the fibres, but viscous heat dissip ation is enhanced.