PET切片低聚物的萃取工艺及其表征

Characterization and extraction technique of oligomers in PET

采用索氏萃取法从PET切片中提取低聚物,考察了切片尺寸、萃取时间与萃取量的关系;运用分子质量分布、紫外光谱、红外光谱、DSC进行了表征。结果表明:采用氯仿做萃取剂,80℃下连续回流提取18 h可作为常规PET切片低聚物萃取终点的定量方法;提取出的低聚物是混合物,其主要成分为环状三聚物;环状低聚物在PET熔融结晶过程中起到了结晶成核剂的作用。

The extraction technique of oligomers from PET chip was studied by soxhlet extraction, the size of PET chips and time of extraction on the extraction quantities of oligomers was investigated. The oligomers was characterized by molecular weight distribution, UV and FT-IR spectrum, DSC. The study results showed that extraction end point can be determined by continuous reflux extraction for 18 hours at 80 ℃ as quantitative method for normal PET chips by chloroform as extraction menstrual; The extracted oligomers was mostly cyclic trimer; The cyclic oligomer acts as nucleating agent during the process of PET melt crystallization.