Gzyra-Jagieła Karolina, Sulak Konrad, Draczyński Zbigniew, Podzimek Stepan, Gałecki Stanisław, Jagodzińska Sylwia, Borkowski Dominik
Lukasiewicz Research Network-Institute of Biopolymers and Chemical Fibres, 19/27 M. Skłodowskiej-Curie Street, 90-570 Łódź, Poland.
Faculty of Material Technologies and Textile Design, Lodz University of Technology, 116 Żeromskiego Street, 90-924 Łódź, Poland.
Polymers (Basel). 2021 Oct 23;13(21):3651. doi: 10.3390/polym13213651.
Plastic products, especially in the packaging industry, have become the main commodities penetrating virtually every aspect of our lives. Unfortunately, their omnipresence is not neutral to the natural environment. Pollution in the form of microplastics is a global problem. Therefore, green technologies that enter into the circular economy become an important topic. As part of the research work, the modification of poly(lactic acid) has been studied for use in the packaging industry. Due to its intrinsic rigidity, plasticizing substances had to be introduced in PLA in order to improve its plastic deformability. Both high-molecular compounds such as ethoxylated lauryl alcohol, block copolymer of ethylene oxide and propylene oxide, and ethoxylated stearic acid as well as low-molecular compounds such as di-2-ethylhexyl adipate, di-2-ethylhexyl sebacate, and triethyl citrate were used. The samples extruded from plasticized polymers were characterized using differential scanning calorimetry, thermal gravimetric analysis, and mechanical properties including Young's modulus. The melt flow rate (MFR) and molar mass distribution were determined. For all modified samples the glass transition temperature, depending on the plasticizer used, was shifted towards lower values compared to the base polymer. The best result was obtained for di-2-ethylhexyl adipate (ADO) and di-2-ethylhexyl sebacate (SDO). The elongation at break increased significantly for ADO at about 21%. The highest elongation was obtained for SDO (about 35%), although it obtained a higher glass temperature. The degradation of the polymer was not observed for both plasticizers. For these plasticizers (ADO and SDO) it also lowered Young's module by about 26%, and at the infrared spectrum deformation of peaks were observed, which may indicate the interaction of the ester carbonyl group of PLA with plasticizers. Therefore it can be concluded that they are good modifiers. The selected plasticizers that are used in the production of food contact materials, in particular in the production of PVC (polyvinyl chloride) food films, also exhibited great potential to be applied to PLA food films, and exhibit better properties than the citrate, which are indicated in many publications as PLA plasticizers.
塑料制品，尤其是在包装行业，已成为几乎渗透到我们生活方方面面的主要商品。不幸的是，它们的无处不在对自然环境并非没有影响。微塑料形式的污染是一个全球性问题。因此，融入循环经济的绿色技术成为一个重要课题。作为研究工作的一部分，已对聚乳酸的改性进行了研究，以用于包装行业。由于其固有的刚性，必须在聚乳酸中引入增塑剂以提高其塑性变形能力。使用了高分子化合物，如乙氧基化月桂醇、环氧乙烷和环氧丙烷的嵌段共聚物以及乙氧基化硬脂酸，还有低分子化合物，如己二酸二-2-乙基己酯、癸二酸二-2-乙基己酯和柠檬酸三乙酯。使用差示扫描量热法、热重分析以及包括杨氏模量在内的力学性能对增塑聚合物挤出的样品进行了表征。测定了熔体流动速率（MFR）和摩尔质量分布。对于所有改性样品，取决于所使用的增塑剂，玻璃化转变温度与基础聚合物相比向较低值移动。己二酸二-2-乙基己酯（ADO）和癸二酸二-2-乙基己酯（SDO）取得了最佳结果。ADO的断裂伸长率显著增加，约为21%。SDO获得了最高的伸长率（约35%），尽管它的玻璃化温度较高。两种增塑剂均未观察到聚合物降解。对于这些增塑剂（ADO和SDO），它还使杨氏模量降低了约26%，并且在红外光谱中观察到峰的变形，这可能表明聚乳酸的酯羰基与增塑剂之间的相互作用。因此可以得出结论，它们是良好的改性剂。在食品接触材料生产中使用的选定增塑剂，特别是在聚氯乙烯（PVC）食品薄膜生产中使用的增塑剂，在应用于聚乳酸食品薄膜方面也表现出巨大潜力，并且比许多出版物中作为聚乳酸增塑剂指出的柠檬酸盐表现出更好的性能。
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