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测定聚对苯二甲酸乙二酯(PET)分子量的方法很多,目前国内PET的生产厂几乎都用特性粘数表征其分子量的大小.以稀溶液粘度法进行PET分子量测定中,所用溶剂多为酚类单一溶剂,或与卤代烃类组成的混合溶剂,其中又以苯酚-四氯乙烷应用得较为普遍.由于溶剂中二组分比例的变化,会对特性粘数的测定结果带来明显影响,从而使按文献上的〔η〕=KM~α公式计算的同一PET试样的分子量各不相同,这就给PET的生产控制和产品质量检验造成了困难.
There are many ways to determine the molecular weight of polyethylene terephthalate (PET). At present, almost all domestic PET manufacturers characterize their molecular weight by intrinsic viscosity. In the determination of PET molecular weight with dilute solution viscosity, most of the solvents used are Phenol single solvent, or mixed solvents with halogenated hydrocarbons, of which phenol - tetrachloroethane is more commonly used due to changes in the proportion of the two components of the solvent, will result in the determination of intrinsic viscosity So that the molecular weight of the same PET sample calculated according to the formula of [η] = KM ~ α in the literature is different, which makes it difficult to control the production and quality of PET products.