Studies on thermal decomposition are presented for various isomers of poly (phenylene phthalamide) (PPPA). The major thermal decomposition products identified are benzene, aniline, benzonitrile, and phenylenediamine isomers. Production of larger amount of amines was found for the meta-rich PPPA. This is explained in terms of a tentative non-radical process including an overlapping of benzene rings. The process for amine-production from PPPA in the thermal decomposition accounts for the decomposition at the lower temperatures of meta-rich PPPA recognized by the thermogravimetry.

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Investigation is made about the applicability of the time-temperature superposition principle to quickly and simply estimate creep properties, which influence the draining functions of geotextiles (especially non-woven fabrics) which are used abundantly in public works and building constructions. It is found that the time-temperature super-position principle as applied to polyester and polypropylen non-woven fabrics is effective for predicting long period creep properties. Also it is found by analyzing retardation spectrum that there are two stages in the compressive creep process of polyester nonwoven fabrics.

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