용융 시간에 따른 PTT/PET 용융 블렌드의 열적 특성 변화

초록

Melt blends of poly(trimethylene terephthalate) (PTT) and poly(ethylene terephthalate) (PET) of various ratios were prepared by mixing at 280 ℃ for different times using twin screw type internal mixer, and their thermal properties were investigated by DSC, DMA and NMR spectroscopy. With increase in mixing time at 280 ℃, the two melting peaks of PTT/PET blends, corresponding to the melting of PTT and PET, merged to one peak and moved to lower temperatures, while the crystallization temperature moved to higher temperatures. DMA analysis indicated a single glass transition temperature for the PTT/PET melt blends of various compositions prepared by mixing at 280 ℃ for 5 minutes, indicating that the blends are completely miscible in the amorphous region. The transesterification reaction in the PTT/PET melt blends was confirmed by NMR spectroscopic analysis. Degree of randomness and sequence length of the blends were calculated by using 13C-NMR data. The former increased while the latter decreased as themelt mixing time increased.

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