PET熔融缩聚与溶液解聚形成环状低聚物的对比分析

doi:10.16085/j.issn.1000-6613.2022-1966

摘要/Abstract

摘要：

采用萃取法提取聚对苯二甲酸乙二醇酯（PET）在熔融缩聚时产生的环状低聚体，以及采用溶液解聚法制备PET环状低聚体，表征并对比了不同制备方法得到的环状低聚体的结构、组分分布及其热性能。结果表明：熔融缩聚中的萃取法以及借助二苯醚和正十六烷的溶液解聚法均能有效制备环状低聚体，其中二苯醚法得到的产率最高，达80%，而萃取法得到的产率最低；制备的环状低聚体中环状三聚体含量最高，萃取法和二苯醚法制备的环状低聚体具有较宽的环组分分布，正十六烷法制备的产物分布较窄；萃取法和二苯醚法制备的低聚体在190℃、270℃、310℃附近出现吸热峰，而正十六烷法只在280℃、310℃附近出现吸热峰，对应组分分析中产物的熔点；三种方法制备的环状低聚体均具有良好的热稳定性。

关键词: PET回收, 环状低聚体, 溶剂萃取, 环解聚

Abstract:

The cyclic oligomers were prepared by extraction method in melting polycondensation of polyethylene terephthalate (PET) and cyclodepolymerization method, respectively. The structure, component distribution and thermal properties of the cyclic oligomers obtained by the different preparation methods were systematically characterized. The results showed that both the extraction method in melt polycondensation and the cyclodepolymerization method with the aid of diphenyl ether and n-hexadecane were effective in the preparation of cyclic oligomers with the highest yield of 80% obtained by the diphenyl ether method and the lowest yield obtained by the extraction method. The cyclic oligomers products had the highest content of cyclic trimers and the cyclic oligomers prepared by the extraction and diphenyl ether method had a wide ring distribution, while the cyclic oligomers prepared by the n-hexadecane method had a narrow ring distribution. The oligomers prepared by the extraction and diphenyl ether methods indicated endothermic peaks around 190℃, 270℃ and 310℃, while the n-hexadecane method only showed endothermic peaks around 280℃ and 310℃, which corresponded to the melting points of the products. The cyclic oligomers prepared by the three methods all had good thermal stability.

Key words: PET recycling, cyclic oligomer, solvent extraction, cyclodepolymerization

中图分类号:

TQ342.21

钱思甜, 彭文俊, 张先明. PET熔融缩聚与溶液解聚形成环状低聚物的对比分析[J]. 化工进展, 2023, 42(9): 4808-4816.

QIAN Sitian, PENG Wenjun, ZHANG Xianming. Comparative analysis of forming cyclic oligomers via PET melt polycondensation and cyclodepolymerization[J]. Chemical Industry and Engineering Progress, 2023, 42(9): 4808-4816.

图/表 13

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制备方法	产率/%
萃取法	1.2
环解聚-二苯醚法	80.5
环解聚-正十六烷法	15.0

制备方法	产率/%
萃取法	1.2
环解聚-二苯醚法	80.5
环解聚-正十六烷法	15.0

制备方法	聚合度（n）/%
制备方法	2	2_(DEG)	3	4	5	6	7	8	9
萃取法	2.48	3.71	68.23	6.59	8.93	4.94	3.22	1.28	0.63
环解聚-二苯醚法	—	1.04	84.00	3.80	6.47	3.22	1.47	—	—
环解聚-正十六烷法	—	—	81.68	9.86	4.09	2.27	2.12	—	—

制备方法	聚合度（n）/%
制备方法	2	2_(DEG)	3	4	5	6	7	8	9
萃取法	2.48	3.71	68.23	6.59	8.93	4.94	3.22	1.28	0.63
环解聚-二苯醚法	—	1.04	84.00	3.80	6.47	3.22	1.47	—	—
环解聚-正十六烷法	—	—	81.68	9.86	4.09	2.27	2.12	—	—

聚合度（n）	[M_n+H]⁺	[M_n+Na]⁺	[M_(DEG)n+H]⁺	[M_(DEG)n+Na]⁺
2	385.3	407.3	429.4	451.4
3	577.5	599.5	621.6	643.6
4	769.7	791.7	813.7	835.7
5	961.9	983.8	1005.9	1027.9
6	1154.0	1176.0	1198.1	1220.1
7	1346.2	1368.2	1390.3	1412.2
8	1538.4	1560.4	1582.4	1604.4
9	1730.5	1752.5	1774.6	1796.6