Inhibited transesterification of poly(butylene terephthalate)/poly(ethylene terephthalate)/SiO_2 nanocomposites by two processing methods

摘要

Nanocomposites composed of SiO_2 nanoparticles and a poly(butylene terephthalate) (PBT)/poly(ethylene terephthalate) (PET) binary blend were prepared by melt blending in a twin-screw extruder. The phase morphology, crystallization behavior, and transesterification of the nanocomposites were investigated by field emission scanning electron microscopy (FE-SEM), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) spectroscopy, etc. The effects of microstructure and interfacial reaction on the mechanical and thermal properties of the nanocomposites are discussed in detail. Owing to the excellent dispersion of SiO_2 nanoparticles in the PBT/PET matrix, the transesterification between PBT and PET was inhibited and the melting point was increased in the presence of SiO_2 nanoparticles. SiO_2 nanoparticles in PBT/PET/SiO_2-1, produced by a one-step method, had a more effective inhibition of transesterification between PBT and PET than that in PBT/PET/SiO_2-2 produced by a master batch method, with the former exhibiting the best properties.