Crystallisation Behaviours of Poly(ethylene terephthalate)-co-Poly(ethylene 2,6-naphthalate) Block Copolyesters

摘要

Poly(ethylene terephthalate) (PET) and poly(ethylene 2,6-naphthalate) (PEN) were first synthesised individually and then copolymerised to form PET-co-PEN (TN) block copolyesters in different molar weight ratios. The sequence distribution, miscibility, crystallisation behaviour, and crystal structure of TN block copolyesters were analysed using nuclear magnetic resonance spectrometry, dynamic mechanical analysis (DMA), differential scanning calorimetry, and wide-angle X-ray diffraction (WAXD), respectively. The values of the random parameter B of TN copolyesters were between 0.85 and 0.96, demonstrating that TN copolymers are random block copolymers. DMA revealed a single tan δ peak in all TN copolyesters, indicating the high miscibility of PET and PEN. The WAXD deconvolution results revealed that the crystals of the TN copolyester were observed when the PEN ratio was in the range of 10-30 mole%. All of the crystals of the TN copolyesters were associated with PET as the host crystal, and the number-average sequence length was greater than 3 when the crystals were obtained in the TN copolyesters.