Non-linear viscoelastic behavior of some polymers and their composites.

摘要

Constant load creep data were obtained for four plastics: polyethyline,polypropylene, nylon, and polycarbonate. Viscoelastic responses ofthese materials proved to be non-linear in both time and stress. Anempirical creep equation, based on a time dependent retardation rateconstant, was developed to characterize the creep behavior and good correlationwas obtained for various stress levels. By assuming the developedrelationship to be an equation of state, creep behavior of simplecomposites of plastics was predicted with good results when viscoelasticresponses of the components were similar. The importance of stress-timehistory is demonstrated by using the creep equation to estimate mechanicalbehavior in other modes of testing. The concept of a retardation spectrumand its application to the materials studied is considered.