熔纺有机纤维/聚丙烯中富β晶仿生界面增强相的构建与调控

High-performance polypropylene (PP) is essential to the national development of lightweight equipment. Melt-spun organic fiber reinforced PP has huge potential in this area, and the interfacial strength, as an important point, greatly affects its practical application effectiveness. According to interfacial crystallization can enhance the interfacial strength of PP based composites , aim at solving the current problem of tailoring the crystalline structure of interface, as well as further releasing the interface reinforcing effect of interface crystals, the self-assembling β nucleating agent will be introduced into the interfacial modification area of melt-spun organic fiber/PP composite. By adjusting the maximum heating temperature and concentration gradient of β nucleating agent in the interface and nearby region, the β nucleating agent will be controlled to self-assemble into fibrous and dendritic crystalline templates at the interface of fiber/PP system. The cirrus-like interface crystals with rich β-modification embedded in the PP matrix will then be induced growing from the fiber surface. At the meantime, the corresponding controlling mechanism will be explained. Further, the impact of arrangement, growth thickness and crystalline structure of cirrus-like interface crystals with rich β-modification on the interfacial strength of fiber/PP composite will be studied, as well as the relative mechanism. Ultimately, the interfacial strength of melt-spun organic fiber/PP composite will be enhanced greatly. As a result, this project will build a new technology to increase the interfacial strength of melt-spun organic fiber/PP system on the basis of crystal-tailoring technology, and promote the methodology development of reinforcing the interface of PP based composites.

聚丙烯（PP）的高性能化对国家发展轻量化装备至关重要。熔纺有机纤维增强PP在这方面潜力巨大，界面强度则是左右其应用与实施效果的关键。本项目根据界面结晶能提升PP基复合材料界面强度的特点，针对纤维/PP界面晶体形态结构调控困难，界面结晶界面增强效果存在明显提升空间的现状，将可自组装β成核剂引入熔纺有机纤维/PP界面改性领域，通过改变最高加热温度与纤维/PP界面β成核剂的浓度梯度，调控β成核剂在纤维/PP界面自组装成纤维状和树枝状结晶模板，诱导纤维表面形成嵌入PP基体的富β晶仿触须界面结构，建立调控机理。研究纤维/PP界面富β晶仿触须界面结构的界面增强作用，建立其形态组成、生长厚度、排列方式和晶体结构与界面强度的关系，阐明β晶和仿触须形态的界面增强机理，实现熔纺有机纤维/PP界面强度的大幅提高。建立基于界面晶体结构调控的熔纺有机纤维/PP界面增强新技术，促进PP基复合材料界面增强方法的发展。

聚丙烯（PP）综合性能优良、应用广泛，提升其力学性能已成为高分子材料科学领域的重要课题之一。在PP中添加纤维增强体是实现其综合力学性能提高的有效途径，而界面强度是决定其最终效果的关键。本项目将可氢键自组装β成核剂引入熔纺有机纤维，通过复合材料加工过程中成核剂的可控释放与界面自组装，形成了富β晶仿生界面晶体结构，大幅提升了纤维/PP复合材料界面强度和纵横向拉伸性能，系统研究各因素间关系，为利用界面结晶提升PP基复合材料界面强度和宏观性能提供了新途径，达到预期目标：（1）明确酰胺类β成核剂诱导形成β杂化串晶的临界条件和调控方法，揭示了其结构特点，建立了其结构演化与外部温度和力场条件的关系，明确了其对PP力学性能的有益效果和作用机制；（2）研究了所选β成核剂与不同化学结构熔纺有机纤维的相互作用关系，明确了只有具有较大的化学相似性，可形成分子间氢键等条件，才可通过热熔共混实现成核剂的分子级分散，从而实现其高效、可控迁移；（3）研究了成核剂对纤维机械性能的影响，发现因为成核剂小分子与纤维分子链间的氢键作用，可在纺丝过程中提升纤维大分子链和晶片取向度，从而有效提升纤维的拉伸性能；（4）研究了温度条件与负载浓度耦合作用下，富β晶仿生界面晶体结构的形成条件，及形貌特征、晶体结构特点和梯度结构的演变规律，建立了其结构、尺寸与排列密度等与复合材料界面强度和纵横向拉伸性能的关系，获得优化工艺，研制了程序控温高精度热压成型机，制备了纵横向拉伸性能显著提高的单丝增强PP复合材料，建立了基于界面形态调控和仿生概念的纤维增强PP基复合材料界面晶体控制生长新原理新方法；（5）发表科技论文19篇，其中SCI论文8篇，获授权中国发明专利4项，培养硕士研究生5人。