The influence of residual stresses on the mechanical and thermal properties of injection moulded ABS copolymer

Abstract

The mechanical and thermal properties of acrylonitrile-butadiene-styrene copolymer (ABS) were determined for as-moulded and annealed specimens in order to assess the influence of residual stresses on these properties. Mouldings were heat treated at temperatures below and above the glass transition temperature, T _g. Annealing below the glass transition removes most of the residual stresses arising during the moulding process, while annealing above the glass transition temperature removes both the residual stresses and molecular orientation. Residual stresses have a strong bearing on the end-use properties. The thermal behaviour of the mouldings are mostly affected by the stimulation of molecular motion caused by the relaxation of the residual stresses near the glass transition temperature.