聚对苯二甲酸乙二醇酯拓扑结构扩链的流变性和发泡性能

摘要/Abstract

摘要： 为了通过设计具有拓扑长链的结构，增强聚对苯二甲酸乙二醇酯(PET)的熔体模量，改善其发泡性能，分别采用多官能团酸酐扩链剂均苯四甲酸酐(PMDA)和环氧扩链剂四环氧丙基二氨基二苯甲烷(TGDDM)对PET进行反应挤出改性。以核磁氢谱分析PET改性前后的化学结构，利用旋转流变仪和转矩流变仪对PET熔体的流变性能进行表征，同时通过化学发泡法研究改性PET的发泡性能。结果表明：两种扩链剂均成功对PET进行了拓扑扩链改性，且与PMDA相比，TGDDM改性PET具有更高的复数黏度、储能模量、更低的损耗因子值。两种扩链剂协同改性PET时，反应速率明显加快，复数黏度、储能模量较高。当PMDA质量分数为1.0%时，或TGDDM质量分数为0.7%时，改性PET内部开始出现凝胶结构。发泡实验结果表明PET经改性后发泡性能得以改善。

关键词: 聚对苯二甲酸乙二醇酯(PET), 酸酐扩链剂, 环氧扩链剂, 流变, 发泡

Abstract: Polyethylene terephthalate (PET) is widely used in fibers, bottle sheets and films because of its excellent physical properties. It is also one of limited materials have been realized industrial recyclization. Therefore, the development of foaming PET is of great significance to solve the pollution of express packaging waste. However, conventional PET has low molecular weight and straight chain, and its melt viscosity and elasticity are poor. It is difficult to form foam with complete cellular structure and good foaming properties.
In this paper, based on the topological branching chain extension mechanism of PET, the topological chain extension modification of PET was carried out by reactive melt extrusion with multi-functional epoxy modifier and multi-functional anhydride modifier. PET was modified by tetraglycidyl diamino diphenyl methane (TGDDM), and the modification effect was compared with that of pyromellitic dianhydride (PMDA). The reaction ability of TGDDM to PET was analyzed. The rheological properties of PET were improved by extrusion modification with different amounts of chain extender PMDA/TGDDM. The basic performance, thermal properties and rheological properties of the modified PET were compared with those modified with single chain extender. The optimized TGDDM-modified PET, PMDA-modified PET and TGDDM/PMDA-modified PET with superior rheological properties were used as the raw materials, chemical foaming method, foamed via chemical foaming method. The cell morphology of the foamed samples was observed by scanning electron microscope to determine the internal relationship between foaming properties and rheological properties. The effects of foaming conditions on cell parameters were also studied through adjusting foaming temperatures, foaming times and foaming agent contents. The results show that both two chain extenders have successfully modified PET. Compared that with PMDA, PET modified by TGDDM has higher complex viscosity, higher storage moduli and lower loss factor. When two chain extenders cooperate to modify PET, the reaction rate is obviously accelerated, and the complex viscosity and storage modulus are even higher. When the mass fraction of PMDA is 1.0%, or the mass fraction of TGDDM is 0.7%, the gel structure begins to generate in the modified PET. The results of foaming experiment show that the foaming properties of PET are improved after modification. The foaming properties of T1.0P0 with superior rheological properties and more microgel are outstanding, in which the foaming ratio is 3.8, the average cell diameter is 98 μm, and the foaming density is 2.49×107 cell/cm3.
Compared with the unmodified PET, the modified PET has higher molecular weight and improved melt viscoelasticity as well as foaming properties.

Key words: polyethylene terephthalate (PET), anhydride chain extender, epoxy chain extender, rheology, foaming

中图分类号:

TQ328

南婧文, 周　锦, 黄文健, 王秀华, 张须臻. 聚对苯二甲酸乙二醇酯拓扑结构扩链的流变性和发泡性能[J]. 现代纺织技术, 2023, 31(5): 86-95.

NAN Jingwen, ZHOU Jin, HUANG Wenjian, WANG Xiuhua, ZHANG Xuzhen. Topological structure chain extension modification of polyethylene terephthalate (PET) and its rheological behavior and foaming properties[J]. Advanced Textile Technology, 2023, 31(5): 86-95.

参考文献

[1]TAPIA-BLÁCIDO D R, AGUILAR G J, DE ANDRADE M T, et al. Trends and challenges of starch-based foams for use as food packaging and food container[J]. Trends in Food Science & Technology, 2022, 119: 257-271.
[2]CHEN L, WANG S H, WANG S S, et al. Scalable production of biodegradable, recyclable, sustainable cellulose–mineral foams via coordination interaction assisted ambient drying[J]. ACS Nano, 2022, 16(10): 16414–16425.
[3]杨学萍, 刘革. 废旧聚对苯二甲酸乙二醇酯化学回收技术进展[J]. 石油化工技术与经济, 2022, 38(3): 48-52.
YANG Xueping, LIU Ge. Progress in chemical recovery technology of waste polyethylene terephthalate[J]. Technology & Economics in Petrochemicals, 2022, 38(3): 48-52.
[4]成晓燕, 马海燕, 秦维秀. 聚对苯二甲酸乙二醇脂回收料扩链增黏改性研究[J]. 化工新型材料, 2021, 49(2): 244-248.
CHENG Xiaoyan, MA Haiyan, QIN Weixiu. Study on chain extension and viscosity modification of R-PET[J]. New Chemical Materials, 2021, 49(2): 244-248.
[5]XANTHOS M, YOUNG M, KARAYANNDIS G P, et al. Reactive modification of polyethylene terephthalate with polyepoxides[J]. Polymer Engineering & Science, 2001, 41(4): 643-655.
[6]Dolatshah S, Ahmadi S, Ershad-Langroudi A, et al. Rheological/thermal properties of poly(ethylene terephthalate) modified by chain extenders of pyromellitic dianhydride and pentaerythritol[J]. Journal of Applied Polymer Science, 2021, 138(9): 49917.
[7]LIU H M, WANG X D, ZHOU H F, et al. The preparation and characterization of branching poly(ethylene terephthalate) and its foaming behavior[J]. Cellular Polymers, 2015, 34: 63-94.
[8]YANG Z P, XIN C L, MUGHAL W, et al. High-melt-elasticity poly(ethylene terephthalate) produced by reactive extrusion with a multi-functional epoxide for foaming[J]. Journal of Applied Polymer Science, 2018, 135(8): 45805.
[9]BOCZ K, MOLNáR B, MAROSI G, et al. Preparation of low-density microcellular foams from recycled PET modified by solid state polymerization and chain extension[J]. Journal of Polymers and the Environment, 2019, 27(2): 343-351.
[10]Japon S, Leterrier Y, Månson J A E. Recycling of poly(ethylene terephthalate) into closed-cell foams[J]. Polymer Engineering & Science, 2000, 40(8): 1942-1952.
[11]HäRTH M, DöRNHöFER A, KASCHTA J, et al. Molecular structure and rheological properties of a poly(ethylene terephthalate) modified by two different chain extenders[J]. Journal of Applied Polymer Science, 2021, 138(13): 50110.
[12]杨兆平, 信春玲, 何亚东. 环氧基低聚物改性聚对苯二甲酸乙二醇酯的流变性能和发泡性能[J]. 北京化工大学学报(自然科学版), 2017, 44(6): 50-55.
YANG Zhaoping, XIN Chunling, HE Yadong. Rheological behavior and forming properties of polyethylene terephthalate modified with epoxy-based oligomers[J]. Journal of Beijing University of Chemical Technology(Natural Science Edition), 2017, 44(6): 50-55.
[13]LIU H M, WANG X D, LIU W, et al. Reactive modification of poly(ethylene terephthalate) and its foaming behavior[J]. Cellular Polymers, 2014, 33(4): 189-212.
[14]郭亚峰, 信春玲, 杨兆平, 等. PMDA扩链对PET流变性能及发泡性能的影响[J]. 塑料, 2015, 44(6): 45-48, 52.
GUO Yafeng, XIN Chunling, YANG Zhaoping, et al. Foaming performance and rheological properties of chain extended polyethylene terephthalates with PMDA [J]. Plastics, 2015, 44(6): 45-48, 52.
[15]DOLATSHAH S, AHMADI S, ERSHAD LANGROODI A, et al. Long-chain branching of polyethylene terephthalate: Rheological/thermal properties of polyethylene terephthalate/carbon nanotube nanocomposite[J]. Polymer Engineering & Science, 2022, 62(7): 2322-2334.
[16]PANDEY V, SEESE M, MAIA J M, et al. Thermo-rheological analysis of various chain extended recycled poly(ethylene terephthalate)[J]. Polymer Engineering & Science, 2020, 60(10): 2511-2516.
[17]杨鸿昌. 化学交联聚乙烯发泡材料收缩率的研究[J]. 塑料科技, 2018，46(8):38-41.
YANG Hongchang. Study on shrinkage of chemical cross-linked polyethylene foaming material[J]. Plastics Science and Technology, 2018, 46(8): 38-41.
[18]杨忠敏. 聚丙烯泡沫塑料发展趋势分析[J]. 化学工业, 2015, 33(11): 15-17.
YANG Zhongmin. The analysis of polypropylene foam plastics development trend[J]. Chemical Industry, 2015, 33(11): 15-17.