Abstract:

Lignin is the most abundant aromatic polymer in nature. The pulping industry produces millions of industrial lignin annually but high valorization is insufficient. Polymer materials are large in quantity and wide in range but usually come from non-renewable fossil resources which are difficult to degrade. Developing high-performance lignin/polymer composites is of practical significance in realizing the high-volume and high-value utilization of industrial lignin, reducing dependence on fossil resources and decreasing environmental pollution. However, the excessively strong intermolecular forces and easy-to-aggregate characteristics of industrial lignin lead to poor dispersion in polymer materials and result in low material properties. The review summarized recent strategies for improving the interfacial compatibility between lignin and polymers and divided the strategy into high-stress pulverization, compatible addition, chemical modification, aggregation adjustment and interface dynamic bond construction based on the micro-interface interactions. The review detailly evaluated the effects of lignin micro-interface structure and the connecting species with polymers on the strength and toughness of composite materials. It was pointed out that the interface compatibility strengthening was a critical issue for constructing advanced lignin/polymer composites. The economy together with greenness were the key factors affecting the development of advanced composites. Future studies needed to focus on a further fundamental study towards the mechanism of the interfacial interactions between lignin and polymer, develop advanced composites via adjusting the microstructure and aggregation performance of lignin, as well as broaden the valorization of industrial lignin in smart materials, medical materials and others. This review proposed a systematic summary and induction of the design and construction of lignin/polymer composite, which proposed the theoretical basis and research ideas towards the advanced materials development and application in this field.

Key words: lignin, polymer, composite materials, interface strengthening strategies

摘要：

木质素是自然界中储量最高的芳香类聚合物，造纸制浆工业每年会产生数千万吨工业木质素，但高值化利用率不足。高分子材料量大面广，但通常来自于不可再生的化石资源，且难以降解。开发高性能木质素/高分子复合材料对实现工业木质素大批量、高值化利用，缓解对化石资源的依赖，降低环境污染等问题具有现实意义。然而，工业木质素存在分子间作用力过强、分子间易聚集的问题，导致其在高分子材料中分散性能差、复合材料性能低。本文回顾了近年来的木质素/高分子复合材料界面相容性提升策略，从微观界面作用角度将其划分为了高应力粉碎、相容剂添加、化学改性、聚集态调控和界面动态键构建五类。文章详细评述了木质素微观结构及其与高分子的结合方式对复合材料强度和韧性的影响，指出界面相容性强化是构筑高性能木质素/高分子复合材料的核心，强化策略的经济性和绿色性是制备复合材料需要重点考虑的因素。今后的研究需要从机理层面进一步剖析木质素/高分子界面作用本质，针对高分子材料结构特征选择性调控木质素微结构和聚集态，制备高性能复合材料，同时拓宽工业木质素在智能材料、医用材料等新兴领域的利用途径。本文对高性能木质素/高分子复合材料的设计与构筑进行了系统性总结和归纳，对于指导该领域材料的开发与应用提供了理论依据和研究思路。

关键词: 木质素, 高分子, 复合材料, 界面相容性