絮状纳米纤维保暖材料的可控制备及其热输运机制研究

The overweight, low elasticity, and poor thermal insulation performance of the current fibrous thermal insulation materials usually lead to encumbering and inconvenience for wearers, which could not satisfy the requirements of people for lightweight and warm cold-proof clothing. Herein, we will study the fabrication and structure regulation of electrospun flocculent nanofibrous thermal insulation materials, and reveal the collaborative optimization mechanism of the materials structure and thermal insulation performance, finally to obtain lightweight materials with low thermal conductivity. Recently, we have preliminary prepared flocculent nanofibrous thermal insulation materials with a certain thickness through the humidity-induced phase separation of the jets. However, the structure stability and elasticity of these thermal insulation materials could not meet the requirements of practical application yet. Consequently, we will study the controllable fabrication and performance optimization of the flocculent fibrous thermal insulation materials, reveal the mechanism of the fiber formation via the humidity-induced phase separation, and clarify the stability regulating rule of the flocculent nanofibrous structure during the bonding process. Moreover, we will indicate relationship between the bonding structure and mechanical properties, and establish the thermal transportation models for the tortuous porous structure of the flocculent nanofibrous materials. Finally, we will clarify the optimized structure of the flocculent nanofibrous materials, and achieve the target of preparing materials with the density < 10 mg/cm3, thermal conductivity < 0.024 W/m·K, which could satisfy their practical applications in the field of thermal insulation.

当前服装用纤维保暖材料普遍存在重量大、弹性低、保暖性差的缺陷，易导致穿着者臃肿且行动不便，难以满足人们对轻质、保暖防寒服的迫切需求。本项目拟研究静电纺絮状纳米纤维保暖材料的成型及结构调控规律，揭示材料本体结构与保暖性能的协同优化机制，从而获得轻质、低导热的保暖材料。近期申请者通过湿度诱导射流相分离固化成纤，初步获得了具有一定厚度的絮状纳米纤维保暖材料，但其结构稳定性及力学回弹性仍未达到实际应用要求。本项目将开展絮状纤维材料的可控制备及其保暖性能优化研究，揭示湿度诱导下纤维的相分离固化成型机制，明晰纤维原位粘结过程中絮状结构稳定性的调控规律，阐明材料粘结交联结构特征与力学性能的本构关联，建立适用于絮状纳米纤维材料曲孔结构的热传导预测模型，确立材料达到最佳保暖性能时的本体结构特征，实现其体积密度＜10mg/cm3、导热系数＜0.024W/m·K的目标，以满足其在防寒保暖领域的应用要求。

本课题“絮状纳米纤维保暖材料的可控制备及其热输运机制研究”旨在明确絮状纳米纤维集合体的可控制备及其相分离成型机制，揭示原位粘结交联过程中纤维絮状结构稳定性的调控规律，实现高蓬松絮状纤维集合体的可控制备及其在防寒保暖领域的应用。从2017年初开始到2020年末这四年的时间里，开展了大量的实验研究工作：我们系统考察了纺丝原液在非溶剂组分诱导下的静态相分离特性，研究了聚合物纺丝射流在湿度诱导下的动态相分离过程，并探索了环境湿度对纤维本体结构及蓬松絮状结构的影响规律，确立了絮状纤维集合体的湿度诱导相分离成型机制，掌握了调控絮状纤维集合体介观形态的科学方法；通过原位粘结交联反应在纤维内部构建聚合物交联网络，实现了絮状纤维集合体力学性能的有效提升，并考察了原位粘结交联反应对纤维集合体本体结构和力学性能的影响规律，实现了絮状纤维集合体结构稳定性的有效调控；基于湿度诱导相分离机制，我们利用静电纺丝技术制备了瓦楞状结构聚苯乙烯絮状纤维集合体、类羊毛卷曲结构聚偏氟乙烯絮状纤维集合体和层间空隙结构聚砜/聚氨酯絮状纤维集合体，考察了絮状纤维在不同使用环境中的保暖性能，探究了絮状纤维本体结构（孔隙率、孔径和曲折孔道结构等）对其保暖性能的影响规律，确立了材料具有最佳保暖性能时的本体结构特征。经过四年的研究，我们顺利完成了任务书中规定的任务，制备的絮状纳米纤维集合体保暖材料实现了厚度＞20mm、体积密度＜10mg/cm3、导热系数＜0.024W/m·K的目标。项目执行期间共培养博士3名，硕士6名。发表学术论文47篇，申请发明专利10项，授权专利2项。本课题的完成对探究絮状纳米纤维材料的湿度诱导相分离成型机制、实现其可控制备及在防寒保暖领域的应用具有重要意义。