3D打印聚乙二醇修饰木质素/聚乳酸生物复合材料的热性能与力学性能

Thermal and mechanical properties of polyethylene glycol modified lignin/polylactic acid biocomposites for 3D printing

  • 摘要: 聚乳酸(PLA)是一种绿色可再生的、可降解的高分子材料,被认为是目前商业化程度最高的材料。然而,PLA材料主链结构的刚性决定了PLA的冲击强度弱、断裂伸长率低,限制了其在广泛领域的应用。本研究提出了一种双螺杆挤压法制备PLA和聚乙二醇(PEG)修饰木质素生物复合材料的方法,以期能够提升3D打印木质素/PLA复合材料的力学性能,拓展应用领域。对PEG修饰木质素的结构进行了初步研究。研究不同含量的碱木质素和PEG修饰木质素对PLA复合材料的物理力学性能、微观结构、热学性能和降解性能的影响。实验结果表明,采用酸催化PEG脱木质素的工艺能够将PEG接枝到木质素上,同时能够提高木质素的热性能。PEG修饰木质素的加入提高了聚乳酸复合材料的耐热性。与L30/PLA相比,PL30/PLA的拉伸应力和断裂伸长率分别提高了18.1%和81.9%。与纯聚乳酸相比,复合材料在水系统中具有更好的降解率,特别是在碱性介质中。因此,PEG修饰木质素不仅提高了木质素的附加值,而且为高性能PLA复合材料的生产提供了新的途径。

     

    Abstract: Polylactic acid (PLA) is a green, renewable and degradable polymer material, which is considered to be the most commercially available material at present. However, the rigidity of the main chain structure of PLA material determines its weak impact strength and low elongation at break, which limits its application in a wide range of fields. In this study, a twin-screw extrusion method for preparing PLA and polyethylene glycol (PEG) modified lignin biocomposites was proposed, in order to improve the mechanical properties of 3D printed lignin/PLA composites and expand the application field. The structure of PEG modified lignin was studied. The effects of soda lignin and PEG modified lignin on the physical and mechanical properties, microstructure, thermal properties and degradation properties of PLA composites were studied. The experimental results showed that PEG can be grafted onto lignin and the thermal properties of lignin can be improved. The addition of PEG modified lignin increased the heat resistance of PLA composites. With the addition of 30% PEG modified lignin, the tensile properties of the composites did not decrease significantly. Compared with L30/PLA, the tensile stress and elongation at break of PL30/PLA were increased by 18.1% and 81.9%, respectively. Compared with pure PLA, the composite has a better degradation rate in water systems, especially in alkaline media. Therefore, PEG modified lignin not only improved the added value of lignin, but also provided a new way for the production of high-performance PLA composites.

     

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