Thermal expansion, ageing, relaxations and post-cure of polymer composites using modulated temperature thermomechanometry

The glass transition temperature region of polymers and composites has been studied using static force thermomechanometry (sf-TM) and modulated temperature thermomechanometry mT-TM). Modulated temperature allows measurement of linear thermal expansion coefficient and glass transition as reversing phenomena, independent of any residual cure and relaxations that are non-reversing in nature. The reversing dimension change curves were well defined, though sensitivity decreased with crosslinking and fiber content. The non-reversing dimension change curves contained most of the variation, revealed complex changes and the non-reversing characteristic were confirmed by repeated scans, both upon cooling or re-heating.