Aging model for commercial polymers

Physical aging of polyvinyl chloride, high-density polyethylene, and polyester reinforced with polyester fibers specimens have been investigated. These materials are commercially available and are currently used in trenchless relining of sewer pipes. The analysis uses the effective-time theory and time-temperature superposition (TTSP) methods proposed by Struik, as well as variations of these methods, as proposed by Chai and McCrum, Guerdoux et al. and others. The creep data generated by this study show that the time-dependent creep properties of these materials can be modeled within experimental error with slight changes to the above methods. To predict the creep behavior of full-scale specimens; these properties were then shifted from their testing age and temperature to the testing age and temperature of the full-scale specimens. It was shown that a rotation, along with a horizontal shift of the aging data, is needed to obtain the ageing parameter of the materials