The surfaces of the single-component homopolymer
films were, as expected, found to be homogeneous
in appearance and elemental distribution
both before and after heating. However, the films
formed from the mixture of the two polymers
showed the presence of two phases: a matrix within
which were roughly spherical areas of a chlorine-rich
material (see Fig. 1). This indicates the presence of a
partially miscible system. On heating at 170 8C for
30 mins, this structure changed radically, appearing
homogenous in both morphology and chlorine
distribution (see Fig. 2).