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本文在290℃用熔融共缩聚制备了系列PET/PHB共聚酯,用高分辨核磁共振(400MHz ~1H-NMR)研究了PET/PHB共聚酯的序列分布规律。结果表明,PHB组分增加,其选择因子m线性降低。在此基础上,得到了PET、PHB链段平均长度,无规度等一系列序列结构参数,其分布规律与一般共缩聚相似。其无规度比270℃共缩聚样品高。并根据PHB链节数≥4才形成PHB相这一前提,估算了共聚酯PHB相(即液晶相主要成分)理论含量与PHB组分的关系:W_(PHB)％(?)104.0x_(PHB)~(4.40)。最后推测了对PET/PHB共聚酯形成液晶相最低PHB理论含量为1.1％wt。
In this paper, a series of PET / PHB copolyesters were prepared by melt copolycondensation at 290 ℃. The sequence distribution of PET / PHB copolyesters was studied by high resolution nuclear magnetic resonance (400MHz ~ 1H-NMR). The results showed that the PHB component increased, the selectivity factor m decreased linearly. On this basis, a series of sequence structural parameters such as the average length of PET and PHB segments, randomness and so on were obtained, and the distribution rules were similar to those of general copolycondensation. Its randomness is higher than the 270 ℃ copolycondensation sample. According to the premise that the PHB phase is formed when the number of PHB chain linkages ≥4, the relationship between the theoretical content of the PHB phase (ie, the main component of the liquid crystal phase) and the PHB component is estimated: W PHB% 104.0x - PHB) ~ (4.40). Finally, it is presumed that the theoretical content of the lowest PHB in the liquid crystalline phase of PET / PHB copolyester is 1.1% wt.