Abstract
The miscibility, multiple melting behavior and recrystallization of poly(butylene terephthalate)/poly(ether imide) (PBT/PEI) blends have been investigated by differential scanning calorimetry(DSC). The $T_{g}$ of PBT/PEI blends shows a negative deviation from Fox equation, except when the PEI content is higher than 80%. This indicates that PBT/PEI blends are partially miscible. The blending with PEI has a strong effect on the melting behavior of PBT as follows: first as the content of PEI in the blends increases the multiple melting behavior changes from three peaks (low, middle and high peak) to two peaks (middle and high peak); second, the size of high peak relative to that of middle peak becomes smaller with increasing PEI content in the blends. The exotherm peaks arising from recrystallization in the PBT/PEI blends were examined by DSC. Both recrystallization rate and heat of PBT/PEI blends decreased as the content of PEI increased. These results seem to suggest that remixing between PBT and PEI takes place after initial melting of the original PBT crystal, and such a remixing renders more difficult the diffusion of PBT in the subsequent recrystallization.