POLYMER, cilt.49, ss.4703-4712, 2008 (SCI İndekslerine Giren Dergi)
The tensile and compressive properties of triptycene-polycarbonates were tested over 6 orders of magnitude in strain rate. Initially we studied a low molecular weight, low triptycene content PC blended with lupilon (R) PC and then a series of higher molecular weight, higher triptycene content polymers. The PC blend with only 1.9 wt% triptycene displayed up to 20% increase in modulus and up to 17% increase in yield strength with elongations over 80% as compared to the lupilon PC. The higher molecular weight T-PCs (up to 26 wt% triptycene) exhibited improvements in modulus by over 20% and improvements in compressive strengths by nearly 50% at both low and high strain rates without any apparent sacrifice to ductility, as compared to lupilon (R) PC. All samples containing triptycene units retained transparency and exhibited no signs of crystallinity or phase separation. Moreover, both the blends and triptycene-PC copolymers displayed significantly altered dynamic mechanical spectra, specifically, the emergence of a pronounced, new beta' relaxation approximately 75 degrees C above the traditionally observed 0 relaxation in PC (approximately - 100 degrees C). The enhancement of the mechanical properties observed provides valuable insights into the unique packing and interactions during plastic flow induced by the presence of triptycene units. (C) 2008 Elsevier Ltd. All rights reserved.