Research Study of New Concepts to Promote the Failure of Polymers by Stress Cracking

摘要

The study was to develop a new concept on the failure of polymers by stress cracking. Experiments have shown that failure time of treated samples was not influenced by sample size. Sets of material parameters for untreated and treated samples of SBR tread, butyl tread, and polyethylene have been obtained. Exploratory trials of cracking agents on butyl tread produce a 10 to the 7th power reduction in failure time as was found for SBR tread. Cracking agents effective on tread stocks have little effect on polyethylene. An accelerated test for cracking effectiveness is being developed. Surface properties of polymers appear to have a specific influence in cracking effects. Computation of surface energy of polyethylene by three methods is in fair agreement and has established an important guideline in the mechanism of failure. Calcualtion methods for surface energies of binary mixtures was used to evaluate surface energy at maximum swelling of a vulcanized rubber.