纳米纤维素增强凝胶材料界面作用与能量耗散机制研究

The application of cellulose nanocrystals (CNCs) in polymeric materials reinforcement is critical in developing sustainable chemistry and achieving the purpose of biomass high-value utilization. From macro-mechanical behavior, mesoscopic hydrogel network structure, and microscopic interface stress distribution and crack evolution, this project would focus on interface stress transfer and energy dissipation in CNC reinforced hydrogels, study the interaction between CNC and polymer chains, and construct mechanical properties multiscale coupling mechanism. Based on previous work progress, we will systematically study the hydrogels hierarchical features and clarify the effects of interface between CNC reinforcement phase and polymer matrix on stress transfer in hierarchical hydrogel network, pathway of crack evolution, as well as energy dissipation through multiscale experimental exploration and theoretical modelling. We will also delineate the cross-scale mechanical reinforcement mechanism, and elucidate the relations among macro-mechanical performance, mesoscopic aggregated structure, and microscopic polymer chains architecture. Through the exploration of the constitutive relation for CNC reinforcement in hydrogels, it is expected that this project would enrich the basic law of condensed soft matter and provides unique insights for design and regulation of high strength hydrogels.

纳米纤维素增强高分子材料是发展可持续化学和实现生物质高值化利用的重要研究内容。本项目围绕纳米纤维素增强水凝胶材料研究领域界面应力传递与能量耗散为切入点，将宏观力学行为、介观凝胶网络结构和微观界面应力分布及裂纹演化相结合，重点考察纳米纤维素与高分子链之间相互作用规律，并构建纳米纤维素增强凝胶材料力学性能多尺度耦合机制。在前期工作基础上系统研究凝胶材料多层级结构特点，注重多尺度实验分析和理论模型相互结合，阐明纳米纤维素增强相与聚合物基体之间界面作用对具有层级结构的凝胶材料界面应力传递、裂纹演化路径和能量耗散之间的关联效应。研究跨尺度力学增强机制，明晰聚合物在形变过程中宏观力学行为、介观聚集态结构和微观分子链构型之间相互关系。探索纳米纤维素增强凝胶材料界面作用本构关系，丰富纳米纤维素增强软物质凝聚态基本规律内涵，为设计和调控高强度凝胶材料提供理论依据和新的思路。

纳米纤维素增强高分子材料是发展可持续化学和实现生物质高值化利用的重要研究内容。.本项目围绕纳米纤维素增强水凝胶材料研究领域界面应力传递与能量耗散为切入点，把纳米纤维素增强水凝胶材料中界面应力分布及其传递、裂纹产生和演化过程、CNC与裂纹相互作用等基础科学问题作为研究重点，通过宏观力学行为、介观电镜观察和微观光谱等多尺度性能测试，分析典型凝胶网络在应力作用下CNC-基体界面应力分布及裂纹传播规律，建立CNC/裂纹交互作用模型，明确微尺度下界面失效参数（剪切强度、裂纹扩散路径）与界面作用力（共价键/非共价键等）之间耦合机制，为从多尺度角度探索CNC增强凝胶材料中界面应力传递及断裂能量耗散机制提供理论依据。构建宏观-介观-微观多尺度关联测试体系，宏观上测量不同时间尺度下应力-应变行为、介观上通过电镜观察CNC/聚合物界面形貌及CNC取向分布、微观上采用拉曼光谱研究纤维素对载荷响应等微观力学行为，将宏观力学行为、介观形貌和微观应力载荷响应等不同尺度实验结果进行关联，分析具有复杂层级结构的CNC增强凝胶材料力学性能，为优化凝胶材料微观结构、预测凝胶材料宏观力学性能提供可靠的理论依据，丰富软物质材料凝聚态本构关系理论。.