CHARACTERIZATION OF THERMOREVERSIBLE POLYMER GELS BY THE DEGREE OF CRYSTALLINITY BY SURFACE-AREA

A characterization for crystalline junction polymer gels has been exte nded by introducing a new parameter which implies a measure of the num ber of the polymer molecules passing through the crystallizing junctio ns. The parameter has been considered in a theoretical gel melting rel ation derived by Takahashi, Nakamura, and Kagawa and a crystallite siz e distribution has also been considered. The equation obtained was exa mined on ethylene-propylene copolymer gels by using the previous data of melting temperatures determined from DSC, crystallite sizes from x- ray and DSC measurements, and reaction probabilities from C-13-NMR mea surements. Consequently, the parameter was found to be helpful as one additional measure. Also, it was confirmed that the average crystallit e sizes estimated in several different ways were all in good agreement with the conventional data. (C) 1996 John Wiley & Sons, Inc.