ANISOTROPY IN ORIENTED FIBRES FROM SYNTHETIC POLYMERS

On the assumption that synthetic fibres at low strains can be considered as transversely isotropic elastic bodies the five independent elastic compliances have been measured for filaments of low and high density polyethylene, nylon 6.6, polyethylene terephthalate and polypropylene, all at room temperature. Experimental values are compared with those predicted using an aggregate theory which assumes that the partially oriented fibre can be considered as an aggregate of elastic units which are aligned by the drawing process, and whose properties are those of the fully oriented fibre. The applicability of this aggregate theory is discussed, and possible explanations are advanced in those cases where agreement between theory and experiment is unsatisfactory. © 1969 Chapman and Hall.