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采用原位红外分析和DSC分析相结合的方法,研究连续升温过程中不同黏度PET红外光谱特征及聚集态形态特征的变化。结果表明:低黏度PET倾向于生成较厚的片晶结构,在升温时伴随各种相转变过程中,其分子链空间构象间的调整速度均小于高黏度PET;在连续升温过程中,849和896 cm-1或1 340和1 371 cm-1特征峰之间相对强度比的变化,可较好地反映出黏度对PET聚集态形态结构的影响;但不同黏度PET样品的红外光谱特征及聚集态形态特征随温度变化的倾向和规律基本是一致的,且只有当温度超过280℃以上时,样品中和结晶有关的有序结构含量才开始随温度的增高明显下降。
In situ IR analysis and DSC analysis were used to study the changes of IR spectra and morphological characteristics of PET with different viscosity during continuous heating. The results show that PET with low viscosity tends to form thicker platelet structure. During the phase transition, the conformation speed of molecular chain is smaller than that of PET with high viscosity. During the continuous heating process, The change of the relative intensity ratio between 896 cm-1 or 1 340 cm-1 and the characteristic peak of 1 371 cm-1 can well reflect the influence of viscosity on the morphology of PET aggregates. However, the infrared spectra of PET samples with different viscosities and their aggregation states The tendency and regularity of morphological characteristics with temperature are basically the same, and only when the temperature exceeds 280 ℃, the content of ordered structure related to crystallization began to decrease obviously with the increase of temperature.