Abstract: In this work, the crystal morphology and the crystallization process of butadiene-isoprene copolymers (BIC) have been observed by electron microscopy. The crystallinities and the crystallization rates were obtained quantitatively using a linear dilatometer. It was found that at the same temperature, the crystallization rate and the crystallinity decreased with the increase of isoprene content, and for the same sample BIC crystallized most rapidly at the temperature of -65℃— -45℃, According to the experimental results about the crystallization of BIC, the Avrami equation has been revised.

Key words: Butadicne-isoprenc copolymer, Crystallization behaviour, Avrami equation