RESEARCH STUDY OF NEW CONCEPTS TO PROMOTE THE FAILURE OF POLYMERS BY STRESS CRACKING
Abstract
This study is to develop a new concept on the failure of polymers by stress cracking. Results presented cover the following work. Experiments have shown that failure time of treated samples is 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. Calculation methods for surface energies of binary mixtures was used to evaluate surface energy at maximum swelling of a vulcanized SBR stock. Experiments on spreading of orga nic liquids on SBR tread were used for an estimate of surface tension of the tread stock. Comparison of surface tension and solubility parameters of various polymers was made to show agreement with computed surface tension of SBR tread. Cracking tests with substituents on benzene ring are as effective as benzene.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1965
- Accession Number
- AD0470650
Entities
People
- C. F. Stark
- V. P. Tomaselli
- W. E. Wolstenholme