Crystallization kinetics of copolymers

In this chapter the overall crystallization kinetics and spherulite growth rates of the major copolymer types will be presented and analyzed. It should be recalled from the point of view of polymer crystallization that chains containing structurally different repeating units, although chemically identical, are also treated as copolymers. These include branch points and regio defects as well as stereo and geometric isomers. As a matter of convenience, the influence of cross-links will also be included in this chapter. 

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The overall crystallization kinetics of copolymers and their blends have been studied by DSC in the temperature range 1(X)-132°C [69]. For all examined blend compositions a single crystallization exotherm was observed at each T, whereas crystallization of mechanical mixtures of the copolymers showed separated exotherms of each component, thus supporting that the crystallization of melt mixed blends occurred from a homogeneous melt. The overall crystallization rate of copolymers was found to be affected by the copolymer structure and lower than that of PP homopolymer (BP < EP < PP), while the crystallization rate of the blends was intermediate between those of pure components (Fig. 10.12). The kinetics were analyzed by means of the Avrami equation (Eq. 10.14) the calculated values of the Avrami exponent for the blends, with average values of n from... 

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