Transesterification reaction of the BaSO4-filled PBT/poly(ethylene terephthalate) blend

For the poly(butylene terephthalate) (PBT)/poly(ethylene terephthalate) ble nd system, the addition of a barium sulfate (BaSO4) particle, the surface o f which was modified with a titanate coupling agent, suppressed the transes terification reaction. The polyester chain ends, considered one of the main sites of transesterification reactions, were blocked through a chemical re action with the surface hydroxyl groups of the BaSO4 particle; a block copo lymer-like architecture was obtained with a BaSO4 linkage. The formation of the block copolymer-like structure for the polyesters stuck to the BaSO4 p article facilitated crystallization by providing a crystallization nucleus without a significant transesterification reaction, resulting in higher mec hanical properties. (C) 2001 John Wiley & Sons, Inc.