目的 本研究旨在建立一套基于差示扫描量热法（DSC）、傅里叶变换红外光谱（FTIR）和热重分析（TGA）联用的检测策略,系统比较三种技术对再生聚对苯二甲酸乙二醇酯（rPET）中微量聚乙烯（PE）杂质的识别能力,为相关检测标准的制定提供方法学支撑。方法 以PET和PE新料为原料,采用双螺杆挤出机通过母粒稀释法制备PE质量分数为1%、2%、3%、5%的掺混模拟样品。利用上述三种方法对掺混模拟样品进行表征并选取两种实际rPET样品完成方法适用性验证。结果 DSC可检出质量分数≥1%的PE杂质,但更低含量的杂质仍需进一步研究。FTIR依据1 472 cm-1处亚甲基C—H键弯曲振动特征峰,杂质识别灵敏度更高,适用于鉴别微量杂质;TGA由于温度区间重叠较大,检出灵敏度有限,可通过DTG峰形作为辅助判断依据。实际rPET样品分析表明,FTIR可有效检出样品中的PE杂质,DSC和TGA可作为辅助判断依据。结论 DSC适用于rPET中PE杂质的快速初筛;FTIR鉴定微量PE杂质更为可靠;TGA可作为交叉验证的辅助手段。三种方法原理互补,联合使用可提高鉴别结果的准确性,为食品级rPET中聚乙烯杂质检测方法标准的建立提供技术支撑。
Abstract
The work aims to establish a detection strategy based on Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TGA) and systematically compare the ability of the three techniques to identify trace amounts of polyethylene (PE) impurities in recycled polyethylene terephthalate (rPET), providing methodological support for the development of relevant testing standards. Pure PET and PE were used as raw materials, and simulated blended samples with PE mass fractions of 1%, 2%, 3%, and 5% were prepared via the masterbatch dilution method by a twin-screw extruder. The three methods described above were employed to characterize the blended samples, and two actual rPET samples were selected to validate the applicability of the methods. DSC could detect PE impurities with a mass fraction of ≥1%, but PE impurities at lower contents required further study. FTIR, based on the characteristic methylene C—H bending peak at 1 472 cm-1, exhibited higher sensitivity for impurity identification and was suitable for detecting trace impurities. TGA showed limited detection sensitivity due to the considerable overlap between the decomposition temperature ranges of PET and PE, but the DTG peak shape could serve as an auxiliary basis for judgment. Analysis of actual rPET samples indicated that FTIR could effectively detect PE impurities in the samples, whereas DSC and TGA could provide supplementary criteria for judgment. DSC is suitable for rapid preliminary screening of PE impurities in rPET, FTIR is more reliable for identifying trace PE impurities, and TGA can serve as an auxiliary cross-validation tool. The three methods are complementary in principle, and their combined use can improve identification accuracy, providing technical support for the establishment of standard methods for detecting PE impurities in food-grade rPET.
关键词
再生PET /
聚乙烯杂质 /
红外光谱 /
差示扫描量热 /
热重分析
Key words
recycled PET /
polyethylene impurities /
infrared spectroscopy (FTIR) /
differential scanning calorimetry (DSC) /
thermogravimetric analysis (TGA)
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参考文献
[1] BENYATHIAR P, KUMAR P, CARPENTER G, et al.Polyethylene Terephthalate (PET) Bottle-to-Bottle Recycling for the Beverage Industry: A Review[J]. Polymers, 2022, 14(12): 2366.
[2] GU Y, ZHOU G, WU Y, et al.Environmental Performance Analysis on Resource Multiple-Life-Cycle Recycling System: Evidence from Waste Pet Bottles in China[J]. Resources, Conservation and Recycling, 2020, 158: 104821.
[3] ITIM B, PHILIP M.Effect of Multiple Extrusions and Influence of PP Contamination on the Thermal Characteristics of Bottle Grade Recycled PET[J]. Polymer Degradation and Stability, 2015, 117: 84-89.
[4] ALSEWAILEM F D, ALREFAIE J K.Effect of Contaminants and Processing Regime on the Mechanical Properties and Moldability of Postconsumer Polyethylene Terephthalate Bottles[J]. Waste Management, 2018, 81: 88-93.
[5] NEVE H, THORAT S, RADHAKRISHNAN S.Melt Processing Behaviour and Structure Development in Recycled PP Blends with Recycled PET[J]. Progress in Rubber, Plastics and Recycling Technology, 2023, 39(2): 141-155.
[6] KANG Y, KIM D, OH Y, et al.Synergistic Effects of Reverse Kneading Blocks and Compatibilizers in a Twin-Screw Extruder: Boosting Dispersion and Physical Properties of Recycled PP/PET[J]. Polymers for Advanced Technologies, 2026, 37(4): e70589.
[7] 曾严, 张弟俊, 刘桂华, 等. 食品级再生聚对苯二甲酸乙二醇酯中非有意添加物的风险[J]. 包装工程, 2023, 44(19): 23-32.
ZENG Y, ZHANG D J, LIU G H, et al.Risk of Non-intentionally Added Substances in Food Grade Recycled Polyethylene Terephthalate[J]. Packaging Engineering, 2023, 44(19): 23-32.
[8] 曾严, 金莉莉, 朱蕾, 等. 物理回收下再生聚对苯二甲酸乙二醇酯的物理表征及挥发性有机化合物监测[J]. 食品科学, 2023, 44(24): 306-315.
ZENG Y, JIN L L, ZHU L, et al.Physical Characterization and Volatile Organic Compound Monitoring of Recycled Polyethylene Terephthalate under Mechanical Recycling[J]. Food Science, 2023, 44(24): 306-315.
[9] ZHONG H N, SU Q Z, CHEN S, et al.Revealing Contaminants in China's Recycled PET: Enabling Safe Food Contact Applications[J]. Resources, Conservation and Recycling, 2025, 212: 107947.
[10] 张雪芬, 狄春峰, 胡仁其. FTIR、DSC、TGA在汽车用非金属材料鉴定中的应用[J]. 上海塑料, 2020, (03): 57-62.
ZHANG X F, DI C F, HU R Q.Application of FTIR, DSC and TGA in the Identification of Automotive Nonmetallic Materials[J]. Shanghai Plastics, 2020, (03): 57-62.
[11] 叶淋泉, 曾乐, 兰孟琦. 差示扫描量热法测试PET聚酯Tg、Tc、Tm结果的不确定度评定研究[J]. 中国塑料, 2026, 40(04): 90-95.
YE L Q, ZENG L, LAN M Q.Uncertainty Evaluation in the Determination of Glass Transition, Crystallization, and Melting Temperatures of Polyethylene Terephthalate by Differential Scanning Calorimetry[J]. China Plastics, 2026, 40(04): 90-95.
[12] BLANCO A, JUAN R, PAREDES B, et al.Advancing Polypropylene Quantification in Recycled HDPE: A Comparative Study of FTIR, DSC, TREF, and TGIC for Enhanced Plastic Circularity[J]. Polymer Testing, 2025, 149: 108855.
[13] DA SILVA D J, WIEBECK H. ATR-FTIR Spectroscopy Combined with Chemometric Methods for the Classification of Polyethylene Residues Containing Different Contaminants[J]. Journal of Polymers and the Environment, 2022, 30(7): 3031-3044.
[14] YANG J, XU Y P, CHEN P, et al.Combining Spectroscopy and Machine Learning for Rapid Identification of Plastic Waste: Recent Developments and Future Prospects[J]. Journal of Cleaner Production, 2023, 431: 139771.
[15] 薛鹏, 段富华. 聚对苯二甲酸乙二醇酯(PET)材料红外光谱分析方法的比较研究[J]. 合成材料老化与应用, 2025, 54 (06): 25-27+73.
XUE P, DUAN F H. Comparative Study on Infrared Spectroscopy Analysis Methods of Polyethylene Terephthalate (PET) Materials[J]. Synthetic Materials Aging and Application, 2025, 54 (06): 25-27+73.
[16] DA SILVA D J, WIEBECK H. ATR-FTIR spectroscopy combined with chemometric methods for the classification of polyethylene residues containing different contaminants[J]. Journal of Polymers and the Environment, 2022, 30(7): 3031-3044.
[17] PATEL C, PATEL R R.Quantification of Surface Erosion in Polymeric Insulating Material under Electrical Stress Using FTIR, SEM and Edge Detection[J]. International Journal of Materials Engineering Innovation, 2022, 13(1): 33-42.
[1] 刘玉飞, 何敏, 罗筑, 等. 红外光谱法定量研究硅烷自然交联聚乙烯的结构演变[J]. 工程塑料应用, 2015, 43(05): 97-100.
LIU Y F, HE M, LUO Z, et al.Quantitative Research on Structure Evolution of Silane Natural Cross-linked Polyethylene by Infrared Spectrum[J]. Engineering Plastics Application, 2015, 43(05): 97-100.
[18] ROSLI N, ISHAK W H W, AHMAD I. Eco-friendly High-density Polyethylene/amorphous Cellulose Composites: Environmental and Functional Value[J]. Journal of Cleaner Production, 2021, 290: 125886.
[19] AITBELALE R, TIMESLI A.Effect of Functionalized Graphene Addition on Mechanical and Thermal Properties of High Density Polyethylene[J]. Journal of Polymer Engineering, 2023, 43(4): 343-353.
[20] KARAGOZ I, DUYAR H, CAVUSOGLU A, et al.Synergistic Effects on the Mechanical, Thermal, and Morphological Properties of HDPE Composites Reinforced with Walnut Shell and Nano-Calcium Carbonate[J]. Journal of Applied Polymer Science, 2025, 142(37): e57464.
[21] HAMIDI N, ABDUSSALAM N, YAZDANI-PEDRAM M.Upcycling Poly(ethylene terephthalate): Identification of the Recovered Poly(ethylene terephthalate) by Thermogravimetry Analysis[J]. Journal of Macromolecular Science, Part B, 2022, 61(2): 206-224.
[22] 郑家欣, 郭沛, 徐然, 等. 共聚磷酸酯与聚碳酸酯复配对聚对苯二甲酸乙二醇酯阻燃性能和发泡性能的影响[J]. 北京化工大学学报(自然科学版), 2022, 49(06): 40-48.
ZHENG J X, GUO P, XU R, et al.Effect of the Combination of Copolyphosphonate and Polycarbonate on the Flame Retardancy and Foaming Performance of Polyethylene Terephthalate[J]. Journal of Beijing University of Chemical Technology (Natural Science), 2022, 49(06): 40-48.
[23] ALHULAYBI Z, DUBDUB I.Comprehensive Kinetic Study of PET Pyrolysis Using TGA[J]. Polymers, 2023, 15(4): 3010.
[24] MAKHLOUF A, BELAADI A, AMROUNE S, et al.Elaboration and Characterization of Flax Fiber Reinforced High Density Polyethylene Biocomposite: Effect of the Heating Rate on Thermo-mechanical Properties[J]. Journal of Natural Fibers, 2022, 19(10): 3928-3941.
[25] LIU M, HAN B, BAI J, et al.Insights into the Co-combustion Characteristics and Synergistic Effects of Biomass and Polyethylene Plastic under Rapid Heating Conditions[J]. Energy, 2025, 325: 136113.
基金
国家市场监督管理总局技术创新中心（食品相关产品质量与安全）开放基金资助（FRPTIC202505）
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