Abstract: Oriented crystallization of cross linked cis-1,4-polybutadiene was investigated by WAXD and SAXS. The results showed that the samples formed "folded chain"lamellar crystallites rather than "extended chain" crystallites in the stretched state. Because new lamellar crystallites continuosly formed between old ones, the long period decreased and the lateral dimension increased gradually,thus resulting in the increase of crystallinity.

Key words: cis-polybutadiene, oriented crystallization, lamellar crystallite, draw ratio, long period