AN INFRARED DICHROISM INVESTIGATION OF SEGMENTAL ORIENTATION IN DRY AND SWOLLEN POLY(DIMETHYLSILOXANE) NETWORKS

The effects of polymer concentration during network formation and deformation are investigated by infra-red dichroism measurements of segmental orientation in uniaxially strained samples. Experiments are performed on end-linked poly(dimethylsiloxane) networks. The results, consistent with the predictions of the theory of segmental orientation, show that the orientation results predominantly from intramolecular effects in response to network deformation. The contributions to orientation from trapped entanglements and from local intermolecular effects are found to be negligibly small.