绿色高效制备酚醛纤维的结构设计及构效关系研究

Due to the crosslinked networks in fibers, Phenolic fibers (PFs) enjoy the properties including excellent thermal behaviors, and flame resistance. Furthermore, activated carbon fibers prepared by phenolic fibers are applied widely in energy, environmental protection and catalyst load. However, the severe environmental pollution caused by the solution curing keeps rarely involving. In this project, it is suggested that a novel method to achieve a green and efficient preparation of phenolic fiber. A controllable self-curing high molecular weight high-ortho phenolic resin will be synthesized. PFs will be prepared by the crosslinking of as-spun filaments derived from wet-spinning of the linear resin during heat-curing. The molecular structure control method of high-ortho phenolic resin will be researched, and the designed structural self-curing high molecular weight high-ortho phenolic resin will be achieved. The spinning solution will be adjusted for the wet-spinning, and the relationship will be built between spinning/curing conditions and structure/performance of PFs. It will be discovered that the regular pattern of structural inheritance of high-ortho phenolic resin, self-curing phenolic resin, as-spun filaments, and PFs. Finally, the three dimension crosslinked network structure of PFs will be designed, and the relationships between structures and properties will be established.

三维交联结构的酚醛纤维具有优异的综合热性能和阻燃特性，活化制成的酚醛基多孔炭材料亦在能源、环保及负载等领域具有独特的优势。线性酚醛熔融纺丝得到的初生纤维需要在固化溶液中交联形成三维网络，但由此产生的污染、低效问题一直难以解决。本项目拟设计结构可控的自固化高分子量高邻位酚醛，通过湿法纺丝、一步热固化掌握酚醛纤维交联网络的形成规律，从而摈弃溶液固化，实现酚醛纤维的绿色、高效制备。并以高邻位酚醛为模板，实现自固化高邻位高分子量酚醛的分子设计；调节酚醛溶液的纺丝性能，建立纺丝条件、固化程序对纤维结构、性能的关系，从而揭示高邻位酚醛合成、羟甲基化、湿法纺丝及固化过程中的结构继承规律，实现酚醛纤维三维交联结构的可控设计，构筑酚醛纤维结构和性能的构效关系。

酚醛纤维是由苯酚、甲醛等制备的树脂经纺丝后，交联固化得到的功能性纤维。有良好的阻燃、耐温、隔热、耐腐蚀等特性；并具有较高的残碳率，有利于制备酚醛基碳纤维以及酚醛基活性炭纤维，可广泛应用于能源及环境领域。但现有熔融纺丝制备酚醛纤维的方法存在耗时长、污染重的缺陷。.本项目通过高邻位热塑性酚醛树脂的羟甲基化，制备了活化能更低、更易交联反应的热固性高分子量酚醛树脂，通过Kissinger方程对DSC曲线分析发现所得酚醛树脂的固化表观活化能仅为89.54kJ/mol。通过湿法纺丝、固化（微波固化）制得交联的酚醛纤维，通过FTIR、Micro-FTIR、NMR等结构分析发现固化过程中羟甲基相互间发生缩聚反应，在生成水的同时形成亚甲基或亚甲基醚键；在高温下进一步转化为稳定的亚甲基键或碳基键，并伴随着纤维交联度和热稳定性的进一步提高。氮气气氛下热固化得到的酚醛纤维拉伸强度为191MPa，断裂伸长率为10.9%，800℃时残碳率为53.9%，LOI值达到29，获得了性能优异的酚醛纤维，从而实现了酚醛纤维的绿色、高效制备。.最后利用合成的高邻位热固性酚醛树脂溶液静电纺丝、固化获得了纳米酚醛纤维，并利用KOH活化获得了高邻位热固性酚醛基纳米活性炭纤维。通过BET和MB/碘吸附分析了纳米活性炭纤维的孔结构和吸附性能，获得了比表面积高达2606m2/g、MB吸附量为1643.0mg/g、碘吸附量2731.1mg/g的高邻位热固性酚醛基纳米活性炭纤维，实现了低污染、高性能酚醛基活性纳米炭纤维的制备。