ABSTRACT
Attempts to improve the compressive properties of high-performance polymeric fibers are summarized. Special attention is given to chemical modifications designed for intermolecular crosslinking. Issues pertaining to the evidence of crosslinking and the effects of crosslinking on the fiber structure and morphology are discussed. While uncrosslinked, high-performance polymeric fibers (e.g., PBZT) exhibit a fibrillar morphology, a morphological transition from fibrillar to non-fibrillar is 182observed to take place in methyl pendant PBZT fibers on crosslinking. A small degree of crosslinking can result in a significant improvement in compressive strength. However, internal stresses may build-up in the fiber on crosslinking, resulting in low tensile strength. Based on the work to date, it is concluded that intermolecular crosslinking, which does not result in the build-up of stresses within the fiber, will improve the compressive strength of high performance polymeric fibers without a concomitant decrease in tensile strength. An example of a system, in which this may occur, is presented.
