【作者】 常静；

【导师】 冯连芳； 胡国华；

【作者基本信息】 浙江大学 ， 化学工程， 2009， 博士

【摘要】 作为高性能工程塑料中的一类,聚酰胺因具有优良的力学性能和较好的电性能,又具有耐磨、耐高温、耐溶剂、耐化学腐蚀性等特点而备受关注。我国对聚酰胺的研究相对较晚,在工业化过程中仍存在很多技术问题,这些问题的解决依赖于深入的基础研究。从主链结构上考虑,聚酰胺可分为脂肪族和芳香族,不同链结构的聚酰胺在合成方法上有显著的差异。含芳环链结构单元的嵌入,主链刚性逐渐增强,加上氢键作用,使含芳聚酰胺的表征愈加困难。因此,对不同链结构的聚酰胺的合成方法及表征方法的研究具有重要的现实意义。论文分别采用水、N-甲基吡咯烷酮（NMP）和离子液体（IL）为溶剂分别合成了脂肪族聚酰胺、半芳香聚酰胺和全芳香聚酰胺,并进行比较分析;采用三种方法实现了难溶聚酰胺的分子量分布及其结构的表征。论文取得了以下创新性研究结果:以水为溶剂合成聚酰胺共聚物（PA6T-co-66）,考察反应时间和反应温度的影响,最佳反应温度为220℃,最佳反应时间为5h。采用离子液体为溶剂合成聚对苯二甲酸己二胺（PA6T）,与以水为溶剂时的聚合相比,反应时间显著缩短,反应温度显著降低,聚合物的分子量提高且分布变窄;离子液体为溶剂时得到的聚酰胺的熔点和结晶温度均有降低,而对热稳定性影响不大。发现离子液体中的含水量对聚合有显著影响,严格除水的离子液体可回收使用,且回收次数对聚合结果影响不大。以对苯二甲酰氯和对苯二胺为单体,NMP-氯化钙为溶剂,合成了高分子量的全芳聚酰胺PPTA,单体摩尔配比、单体浓度、反应时间、起始反应温度、搅拌转速均对PPTA的重均分子量有影响,其中单体摩尔配比对聚合物分子量影响最为敏感,以TPC稍过量为宜;转速对于聚合分子量的影响主要体现在低转速范围,当转速超过某一临界值时,转速对PPTA分子量几乎没有影响。分别采用含芳聚酰胺乙酰化、全芳聚酰胺烷基化的方法,使难溶聚酰胺溶于四氢呋喃,实现了用GPC表征分子量及分子量分布。结合特性粘度的测定,得到了30℃下PPTA在96%硫酸溶液中的Mark-Houwink方程;综合文献中的数据和本文结果,获得了适用于较宽分子量范围的M-H方程:[η]=6.47×10^-3M_w^1.08mL/g,10⁴≤M_w≤6×10⁴。发展了一种新的用于表征难溶聚酰胺的分子量的方法,即将基质辅助激光解吸电离飞行时间质谱（MALDI-TOFMS）用于表征分子量及分子量分布,获得了离子液体中合成产物PA6T的链结构,表明其主链为线性。将MALDI-TOF MS和GPC两种方法测得的PA6T的平均分子量和分子量分布指数进行对比,表明MALDI-TOF MS测得的平均分子量及分布指数均低于GPC法。MALDI-TOF MS研究表明,PA6T中存在三种端基结构聚合体:两端均为氨基或羧基、或一端为氨基另一端为羧基。分子量提高,脂肪族聚酰胺和半芳聚酰胺的热稳定性和耐热性也升高;端氨基聚酰胺比端羧基聚酰胺更易分解,端羧基PA6T的耐热性高于端氨基PA6T,而端基类型对PA66的熔点和结晶温度影响较小;当主链引入苯环后,熔点和结晶温度大幅增加,最大热分解温度也有升高。用差示扫描量热法考察了不同组成的PA6T-co-66共聚物及PA6T在不同降温速率下的非等温结晶动力学。分别用Avrami、Jeziomy、Ozawa、Mo法分析非等温结晶条件下的结晶行为,得到了相关的非等温结晶动力学参数。用Augis-Bennet,Kissinger和Takhor三种方法得到了样品的非等温结晶活化能,发现活化能随着共聚物中6T含量的增加而增加。更多还原

【Abstract】 As one kind of the high performance engineering plastics, polyamide has been caught the sight for its excellent mechanical property and good electric performance, as well as wear resistance, solvent resistance, chemical resistance high temperature tolerance. The research for polyamide in our country is relative late, and there are many problems in commercial process, which need plenty of fundamental researches. On the other hand, as the consident of main chain structure, polyamde can be classified as aliphatic polyamide and aromatic polyamide, and not only the synthesis methods are significant different for the different structure, but also the the characterization are more difficult for the stronger rigidity of main chain as well as hydrogen bond. So, the study of synthesis and characterization of polyamide with different main chain structure has significant actual meaning.The innovation of this thesis is that synthesis the aliphatic and aromatic polyamide using water, NMP and ionic liquids as solvent and also compares the difference between this two methods. Realize the characterization of the mole mass and structure of the hard-to-dissolve polyamide using three methods. This thesis achieve some results as follow:Using water as solvent to synthesize polyamide copolymer of PA6T-co-PA66, reaction time and reaction temperature has influence on polycondensation result, and obtain polymer with high molecular weight. Comparing with polycondensation in water, the reaction time and reaction temperature are significant decreased when using ionic liquid as solvent to synthesis PA6T, but the molecular weight was increased and the distribution was narrowed. Melting point and crystallization temperature of PA6T obtained in ionic liquid were lowed, and the thermal stability had little changed. The content of water in ionic liquid has obvious influence on polycondensation, so it need to remove water from the used ionic liquids when reusing ionic liquid. Ionic liquid can be reused, and reusing time has little influence on polycondensation.Using terephthalyl chloride and p-phenylene diamine as monomer, and NMP-CaCl₂ as solvent, PPTA with relative high mole mass was synthesized, and the ratio between terephthalyl chloride and p-phenylene diamine, initial monomer concentration, initial temperature, and reaction time all have influence on molecular weight of PPTA. Among them, monomer ratio has sensitive effect on molecular weight.and it was at low rotational speed when it effect molecular weight, and it has little influence on molecular weigh of PPTA when it outrange a certain value.Hard-to-dissolve polyamide can dissolve in THF by acetylation semi-aromatic polyamide and alkylation wholly aromatic polyamide, realize characterization of mole mass and distribution by GPC. Relate the inherent viscosity by viscosimetry with the test result by GPC, M-H equation for PPTA was obtained at the temperature of 30℃and in the solution of H₂SO₄. Combining data in this thesis with data in literature, new numerical value of K and a in M-H equation was obtained, which can be applied for a wide range of molecular weight. Develop a new method to characterization mass distribution of insoluble polymer of polyamide-6,T （PA6T） by matrix assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF MS）. The main chain structure of PA6T polymerized in ionic liquid was analyzed, which was linear without the present of cyclic polymer. The mean mole mass and mass distribution were obtained by MALDI-TOF MS and GPC. It shows that the mean mole mass by MALDI-TOF MS is lower than that by SEC and mass distribution was narrower than that by GPC method.Three structures of end groups were obtained by MALDI-TOF MS, carboxyl group or amino group at both ends or carboxyl group at one end and amino group at the other. The thermal performance of aliphatic and semi-aromatic polyamide with different end groups was investigated. The thermal performace of this two kind polyamide was increased with the increase of molecular weight. Polyamide with amino as end groups was easier decomposed, and the thermal tolerance of PA6T with carboxyl as end groups was higher than that with amino as end groups, for the diacide was terephthalic acide which has benzene ring while the diamide was aliphatic. For PA66, the influence of end groups on melting point and crystallizing point was little. When the main chain has benzene ring, melting point and crystallizing point increased greatly, so as to decomposition temperature.The nonthermal crystallization kinetics of semi-aromatic polyamide and its copolymer was investigated by differential scanning calorimetry at different cooling rate. Crystal behavior in nonthermal crystallization process was analysis by using the classical Avrami equation, Jeziorny, Ozawas equation and Mo method, and kinetics parameters were obtained. The activation energy were calculated according to Augis-Bennet, Kissinger and Takhor, which increase with the content of 6T in copolymer.更多还原