Estimation of polymer crystallinity by dynamic mechanical techniques

Abstract

AbstractDynamic mechanical techniques can be used for a rapid estimation of polymer crystallinity with an accuracy of better than ±20%. The advantage of our proposed procedure is that it is absolute and the crystallinity can be instantaneously estimated when the dynamic mechanical analysis (DMA) data is available. A serious limitation is its applicability to crystallizable polymers (e.g., a quenched nylon 6) where higher values are obtained due to crystallization during the DMA experiment. Another limitation is that our technique cannot be applied to as polymerized samples, e.g., powders or pellets; only fabricated products such as films, fibers, or plaques are suitable for this determination using DMA. Using a variety of polymer systems, the underlying principle, advantages, disadvantages, and recommendations on crystallinity evaluation by DMA are presented. At present we consider this method to be more of a different approach rather than value it as a crystallinity measurement technique, especially for quenched polymers.