A STUDY OF PBT PC BLENDS BY MODULATED DSC AND CONVENTIONAL DSC/

Two poly(butylene terephthalate)/polycarbonate (PBT/PC) blends with di fferent formulations were analyzed by modulated DSC (MDSC) and convent ional DSC to determine differences in crystallization behavior. A sign ificant difference (30 degrees C in cold crystallization temperature) between the two samples was detectable by MDSC while no significant di fference was seen by conventional DSC. That indicates the total heat f low from MDSC is not always equivalent to the heat flow from conventio nal DSC as we have assumed or seen before. The reason has not been ful ly understood, but may be related to unusual nucleation and crystalliz ation induced by modulation. Alternative conventional DSC methods were developed and compared to the MDSC results.