羟基改性苯并唑类聚合物新单体的合成及其树脂纤维探索

发布时间：2018-06-18 07:20

  本文选题：羟基改性PBZ~o + 苯并唑类聚合物与纤维　； 参考：《浙江工业大学》2017年硕士论文

【摘要】：苯并唑类聚合物(PBZ)是一杂环类的聚合物,分二唑与单唑两大类。二唑类以聚对苯撑苯并双VA唑(PBO)为著名,包括双噻唑(PBT)和双咪唑(PBI),其纤维具有高强、高模、耐高温及阻燃等优异特性,已展现巨大的应用前景。而改性PBZ的单体尤其是AB型单体研究渐渐成为目前的研究热点,用它聚合纺丝制备的改性PBZ纤维,着重于改善原纤维存在表面相对惰性,耐压缩性能及紫外稳定性能不足的同时,避免原有工艺带来的问题。本文选择PBZ最简结构的单唑类聚合物(PBZo)并以羟基改性为目标,通过AB型改性PBZo新单体:聚6-羟基-2,5-苯并咪唑(HPBIo)和聚6-羟基-2,5-苯并VA唑(HPBOo)的设计与创制,探索其应用于均缩聚或与PBO单体共缩聚制备羟基和咪唑综合改性PBO树脂与纤维的效果,以提高PBO纤维的轴向抗压能力以及复合粘结性能。研究内容主要包括以下4个方面:首先系统研究了AB型HPBIo单体的关键中间体4-氨基-2-羟基-5-硝基苯甲酸(AHNA)的两种合成技术:以对氨基水杨酸(ASA)为原料,经酰胺化、硝化与水解反应三步法合成AHNA,总收率56.3%,纯度99.21%。以对氨基水杨酸甲酯(MAHB)为起始原料,经硝化和水解两步合成AHNA,总收率66.6%,纯度98.22%。在此基础上,再以AHNA为原料,经还原反应合成AB型HPBIo单体4,5-二氨基-2-羟基苯甲酸(DAHBA),并对水合肼还原工艺进行条件优化后,收率55.3%,纯度98.84%。然后,研究以ASA为原料,经重氮偶合与还原反应合成DAHBA,并对偶合与还原工艺条件进行条件优化,获得总收率为39.4%,纯度为99.04%。同时,以成功合成DAHBA的新路线作参考,探索研究以2,4-二羟基苯甲酸为原料,经重氮偶合反应,还原反应两步合成羟基改性HPBOo纤维单体2,4-二羟基-5-氨基苯甲酸(DHABA),总收率为34.5%,纯度为95.12%。最后,以DAHBA与AB型PBO单体4-(5-氨基-6-羟基苯并VA唑-2-基)苯甲酸铵(ABAA)为单体原料,探索经共聚制备羟基与咪唑综合改性PBO的聚6-羟基-2,5-苯并咪唑/对苯撑苯并双VA唑(HI-PBO)树脂纤维,热分解温度达到552℃,结果表明:HI-PBO分子量越大其耐热温度就越高。本文合成的若干中间体以及新单体的分子结构均经过IR,NMR,MS等定性分析确认。本研究具备新颖性,并具有良好发展的工业化前景,可为推动我国改性PBO纤维的发展提供技术支持。
[Abstract]:Benzoxazole polymer (PBZ) is a heterocyclic polymer, which is divided into two groups: diazole and monazole. Diazoles are famous for their poly (p-phenylene benzobis VA) (PBO), including dithiazolium (PBT) and diimidazolium (PBI). Their fibers have excellent properties such as high strength, high modulus, high temperature resistance and flame retardancy, and have shown great application prospects. However, the study of modified PBZ monomers, especially AB monomers, has gradually become a hot research topic. The modified PBZ fibers prepared by polymerization spinning with the modified PBZ fibers focus on improving the relative inertia of the surface of the original fibers. Compression resistance and UV stability are inadequate, while avoiding problems caused by the original process. In this paper, the simple structure of PBZ, monazole polymer (PBZoo), was selected and the design and creation of new PBZo monomers modified by AB type: poly6-hydroxy-2-benzimidazole-5-benzimidazolium (HPBIoand) and poly (6-hydroxy-2butazole) (HPBOo) were carried out. The results of homopolycondensation or co-condensation with PBO monomers in the preparation of hydroxyl and imidazole modified PBO resins and fibers were explored in order to improve the axial compressive resistance and the composite bonding properties of PBO fibers. The main contents of the study are as follows: firstly, two synthetic techniques of the key intermediate of AB type HPBIo, 4- amino-2-hydroxy-5-nitrobenzoic acid (AHNA), were studied systematically, which were amidation of 4-aminosalicylic acid (ASAA). AHNA was synthesized by three steps of nitrification and hydrolysis. The total yield was 56.3 and the purity was 99.21. AHNA was synthesized from p-aminosalicylic acid methyl ester (MAHBB) by nitration and hydrolysis with a total yield of 66.6% and purity of 98.22%. On this basis, AB type HPBIo was synthesized by reduction reaction using AHNA as raw material. After optimization of the reduction process of hydrazine hydrate, the yield was 55.3 and the purity was 98.84. Then, DAHBA was synthesized by diazo coupling and reduction reaction using ASA as raw material, and the conditions of coupling and reduction were optimized. The total yield was 39.4 and the purity was 99.04. At the same time, with the reference of the new route of successful synthesis of DAHBA, the diazo coupling reaction was studied by diazo coupling reaction with 2o 4-dihydroxybenzoic acid as raw material. The hydroxyl modified HPBOo fiber monomer 2o 4-dihydroxy-5-aminobenzoic acid (DHABA) was synthesized by two-step reduction reaction. The overall yield was 34.5and the purity was 95.12. Finally, the poly (6-hydroxy-2-butadiazole-5-benzobisole HI-PBO) resin fiber modified by hydroxyl and imidazole was prepared by copolymerization of 4-Amino-6-hydroxybenzo-6-hydroxybutazol-2-yl benzoic acid ammonium benzoate (ABAAA) as the monomer of DAHBA and AB type PBO monomers, and the synthesis of poly6-hydroxy-2-benzobisazole-5-benzimidazole / p-benzobisole HI-PBO resin fiber was investigated through the copolymerization of hydroxyl and imidazole. The thermal decomposition temperature reached 552 鈩，

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