Journal of Polymer Science Part B: Polymer Physics, Vol.52, No.23, 1528-1538, 2014
Evolution of Crystalline Orientation and Texture during Solid Phase Die-Drawing of PP-Talc Composites
The objective of the present work was to examine the development of crystalline orientation and texture in the polypropylene matrix of talc-filled i-PP and in unfilled i-PP with increasing draw ratio during solid-phase die-drawing at high strain rates (approximate to 1 s(-1)) and a die temperature of 145 degrees C. After drawing, the entire billet was cooled rapidly under tension to room temperature before releasing the billet and cutting specimens from different axial locations for analysis. Orientation distributions of the three crystal axes for increasing axial strains have been presented as pole figures in the MD-TD plane with the direction of draw (MD) as the reference direction. While disruption of spherulites was noticed within the die for neat PP at a draw ratio of 1.5, transcrystalline domains within the composite persisted even at a draw ratio of 3.5 in the free draw region outside the die. The transformation to fibrillar crystal morphology was complete in both materials at a draw ratio of 4.5 but the texture continued to develop beyond this stage. While the (110)[001] texture component was found to be dominant at all draw ratios for neat PP, the (010)[001] texture component was dominant at the higher draw ratios in the drawn composite. This may be attributed to the (010)[001] slip system being more active as the transverse spacing between elongated voids encasing the particles was decreased. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1528-1538