1. Introduction
Polyvinyl chloride (PVC), a polar and crystalline
polymer, can form physical polymer gels in a wide variety of solvents [1±3] with the formation of fringed
micelle microcrystals as junction points in the network
structure [4±8]. It is well known that atactic PVC is a
low crystalline polymer and the gelation of the semi-dilute solution takes place under a large amount of solvent, so that the crystallization become more difficult.
For example, in our previous result [9] in PVC gel, the
X-ray intensity curve of the gel exhibited only an
amorphous scattering peak mainly due to the scattering intensity of solvents. Guerrero et al. [10] indicated
that the crystallinity of PVC gels strongly depends on
the polymer±solvent interaction. It may imply that the
gelation ability and the physical properties of gels are
related to the polymer±solvent interaction. Our pre-
vious study [11,12] for polyvinyl alcohol (PVA) gels