Chain orientation resulting from the crystallization under strain of poly(epsilon-caprolactone) in miscible blends with poly(styrene-co-maleic anhydride)

Amorphous miscible blends of poly(epsilon -caprolactone) (PCL) with a rando m copolymer of styrene-maleic anhydride (SMA) were stretched at room temper ature and the crystallization of PCL was allowed to develop under strain. T he crystallization of PCL, from oriented amorphous chains, leads to macrosc opic crystalline chain orientation. Using infrared dichroism and wide-angle X-ray scattering techniques, it was found that the resultant crystalline o rientation of PCL is always parallel to the strain direction, regardless of the experimental conditions, which is in contrast with the PCL/poly(vinyl chloride) blend, where both parallel and perpendicular chain orientations c an be induced. Furthermore, the degree of crystalline orientation of PCL is influenced by the initial stretching-induced amorphous chain orientation o f the system. (C) 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1683-16 90, 2001.