Oriented crystallization of crosslinked -1,4-polybutadiene rubber

Saijo, Kenji*; Zhu, Y.*; Hashimoto, Takeji; Wasiak, A.*; Brzostowski, N.*

Crosslink -1,4-polybutadiene (PB) rubber is known to undergo crystallization during mechanical deformation. This article presents small-angle X-ray scattering (SAXS), wide-angle X-ray scattering (WAXS), and stress-relaxation studies of the structural development in crosslinked PB samples crystallized under various orientation regimes. The studies are concerned with isothermal crystallization at various temperatures (10 to -50C) and at constant elongation ratios (1-4,5) and hence with the effects of weak -to-intermediate and high orientations on oriented crystalliation versus the behavior of unoriented specimens. Although the crystallization in the weak-to-intermediate orientations is interpreted on the basis of nucleation growth, the crystallization under high orientations is best interpreted on the basis of spinodal crstallization. To the best of our knowledge, this work reports for the first time spinodal-like crystallization on oriented crosslinked polymer melts.