Long-Term Dimensional Stability of Polycarbonates Reinforced with Glass-Fiber, under Load

Abstract

Polycarbonate is mechanically strong and dimensionally stable. In order to increase its mechanical strength, its reinforcement with glass-fiber was developed, and has been put to practical use.Compression creep tests and tension creep tests of polycarbonates reinforced with glass-fiber were carried out in order to examine mainly the effects of glass-fiber content on the long-term dimensional stability of polycarbonates under load.The following conclusions have been derived.(1) As the glass-fiber content is increased to 30wt% in the tests, the polycarbonate is released much of its initial deformation and of creep deformation rate. Consequently its long-term dimensional stability is much enhanced by reinforcement with glass-fiber.(2) Polycarbonate gains excellent long-term dimensional stability when stress is applied to it in parallel with the orientation of the glass-fiber.(3) There are more deformations in the tension creep tests of samples with glass-fiber content of 0wt% or less at 100°C and 3kg/mm2 than in their compression creep tests under the same condition. There are nearly equal amount of deformations in the compression creep tests and the tension creep tests of samples filled with much glass-fiber.(4) Nutting's equation is applied to the creep data of the samples filled with much glass-fiber. On the other hand, all the creep data after 25 hours are given bylog(e-e0)=alogt+b (t≥25hr)where e is total strain, e0 is initial (Almost instantaneous) strain, t is time, a and b are constants.