The effects of orientation-dependent interactions on the segmental orientation in weakly deformed polymer systems were reexamined on the basis of lattice theories and gas-of-rods theories. Both the freely jointed chain and the wormlike chain were considered as polymer models. It was shown in a somewhat general fashion that the orientation-dependent excluded-volume effect or packing effect could give rise to a considerable amount of excess orientation over that predicted in the absence of such an effect. For a dry system of freely jointed chains comprising rodlike segments of axial ratio 2, for example, the relative excess orientation was estimated to range roughly from 30 to 100%, depending on the theories. This value of the axial ratio seems to approximate the flexibilities of common vinyl polymers, and in this context, the volume effect would never be a minor one even for the “flexible” class of polymers. The nature of and the differences among the various statistical models were discussed in some detail.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry