Particulate reinforced PC/PBT composites. II. Effect of nano‐clay particles on dimensional stability and structure–property relationships

The effect of organoclay loading and surface treatment on the dimensional stability, structure–property relationships, and rheological behavior of nanocomposites consisting of polycarbonate (PC), poly[butylene terephyhalate] (PBT), and nano‐clay was investigated at various clay loadings and with various surface modifiers for the nano‐clay particles. It was found that by using an organoclay formed with a polar amine compound that contained two hydroxyl end groups as opposed to nano‐talc, the flexural strength and tensile toughness of the nanocomposites increased by 12 and 27%, respectively, at a particle loading of 1 wt%, while maintaining the flexural modulus of the nanofilled PC/PBT blends. The flexural and tensile modulus of the nanocomposites increased with an increase in particle loading even though the viscosity was reduced due to a loss of molecular weight of the PC/PBT and/or an increase in the compability of the interface between the PC and PBT phase, which varied with organoclay structure. Possible loss of the molecular weight of the PC/PBT matrix was supported by a significant reduction in the storage modulus and complex viscosity at high frequencies of the composites generated with nano‐clay relative to that of the unfilled matrix. POLYM. COMPOS., 2009.