【作者】 赵婷婷；

【导师】 江建明；

【作者基本信息】 东华大学 ， 材料学， 2007， 博士

【摘要】 聚间苯二甲酰间苯二胺（poly（m-phenyleneisophthalamide）,PMIA）是在1962年首先被合成的一种间位芳香族聚酰胺品种。由于它优异的耐高温与阻燃性能,PMIA的耐高温绝缘纸制品和纤维被最广泛的应用于相应的工业和服装领域。但不管是湿法还是干法纺丝,都要使用大量有挥发性的溶剂。室温离子液体是近年来兴起的一类绿色溶剂,具有不易挥发、稳定性好、熔点范围宽、溶解范围广、易分离回收等优点,近年来多方面的深入研究解决了其对空气和水不稳定的问题,从而广泛应用于电化学、化工分离、化学反应等领域。本论文将离子液体应用于PMIA溶液和纺丝加工体系,尝试将其作为聚间苯二甲酰间苯二胺的良溶剂进行开发利用,研究了PMIA在几种不同离子液体中的溶解过程,尝试分析其溶解机理;并研究了PMIA/离子液体浓溶液的流变行为及其湿法成形工艺,探索用离子液体作为溶剂制备PMIA纤维的技术与工艺。本论文研究中,首先制备了咪唑类的6种离子液体,[BMIM]Cl、[BMIM]BF₄、[BMIM]PF₆、[AMIM]Cl、[EMIM]Br和[EMIM]BF₄,并综合运用多种测试技术,如:核磁共振（NMR）、红外光谱（FTIR）和元素分析实验手段对离子液体的组成与结构进行分析和表征。其次,通过偏光显微镜下的观察,研究了离子液体对聚间苯二甲酰间苯二胺纤维的溶解过程,离子液体作为一种新的PMIA溶剂体系,其溶解机理可以用目前较权威的EDA机理进行解释,处于游离态的阴阳离子充当了电子给予体和接受中心,与PMIA形成的络合作用,削减了PMIA自身的氢键作用,离子液体的不断渗入,破坏了PMIA的聚集态结构,最终被完全溶解。PMIA/离子液体浓溶液流变行为的研究则表明PMIA/离子液体浓溶液属于切力变稀的非牛顿流体,由于离子液体溶剂的粘度高,PMIA/离子液体浓溶液的粘度比PMIA/常规溶剂浓溶液的粘度高。在同一剪切速率下,4种不同离子液体与PMIA组成的溶液表观粘度为ηa（[BMIM]Cl）>ηa（[EMIM]Br）>ηa（[BMIM]BF₄）>ηa（[AMIM]Cl）。产生这一规律的原因是由于离子液体本身粘度的差异性造成的。在210-1000s^-1高剪切速率范围内,高浓度的PMIA/[BMIM]Cl溶液的流变特性表现为溶液体系达到一定浓度时（>14wt%）其粘度随着浓度的升高而下降;这一现象随着浓度的升高而愈发明显。这可能是因为高剪切速率破坏了PMIA/[BMIM]Cl浓溶液中的氢键结构,导致粘度迅速下降。PMIA/离子液体浓溶液的湿法成形实验的研究则表明直接以H₂O为凝固剂,温度为40℃,纺丝原液浓度为18wt%,温度为90℃时,就能满足PMIA的湿法成形要求。随着PMIA/[BMIM]Cl浓溶液中PMIA浓度的增大和牵伸倍数的增加,PMIA纤维的物理机械性能都有所增强。最后,通过TGA、SEM和拉伸性能等测试手段对PMIA纤维制品性能进行了结构与性能的测试,从PMIA/[BMIM]Cl溶液中纺制的PMIA纤维的表面非常光滑,而且纤维截面的空洞也较PMIA/DMAc溶液纺制的纤维截面明显减少,纤维结构致密。而且纤维的取向度和力学性能都要明显好于从传统溶剂DMAc/LiCl中制得的PMIA纤维。特别是,纤维的热性能都要远远好于溶解之前的Nomex纤维,使最终分解温度提高了200℃。更多还原

【Abstract】 A new variety of polyamide poly（m-phenyleneisophthalamide）（PMIA） was first prepared in 1962.Because of its excellent thermal and flame resistance properties,the papers and fibers made from it have been widely used in industrial and clothes applications.It plays an irreplaceable role in the field of high temperature resistance fiber.But both in the process of wet or dry spinning,large amount of deleterious solvents,which are unfriendly to the environment,have been used.They could not meet the requirments of social development.Room temperature ionic loquids（RTILs）is a kind of new developing green solvent,having the advantagement of nonvolatility,good stability,wide liquid range and so on.RTILs have been used extensively in electronic chemistry,chemical reaction,and so on.In this paper,RTILs and PMIA have been combined to study the rheological behaviors and the technology of wet-spinning formation of PMIA/RTILs concentrated solutions, in order to discuss the technology of using RTILs as solvents in the production of PMIA fiber.First,6 RTILs,such as 1-allyl,3-methylimidazolium chloride （[AMIM]Cl）,and 1-butyl,3-methylimidazolium chloride（[BMIM]Cl）,etc were synthesized and characterized by means of FT-IR,NMR and qualitative elementary analysis.Dissolution of PMIA in these RTILs were investigated by means of PLM observation.Experimental results show that RTILs are non-derivatizing solvent,which effect dissolution by disrupting hydrogen-bond between PMIA and[BMIM]Cl and breaking the intramolecular network.Rotational rheometer has been used to study the rheological behaviors of PMIA/RTILs concentrated solutions.The result shows that PMIA/RTILs concentrated solutions are belong to pseudoplastic fluids.And the four different PMIA/RTILs solutions’ viscosity are following:ηa（[BMIM]Cl）>ηa（[EMIM]Br）>ηa（[BMIM]BF₄）>ηa（[AMIM]Cl）.It is interpreted that the difference of these four RTILs could be the reason.PMIA in the concentration range investigated exhibits very different behavior between[Bmim]Cl and DMAc/LiCl solvent.Unlike in DMAc/LiCl solvent,PMIA/[Bmim]Cl solution exhibits maxima in apparent viscosity- concentration plots in the range studied.The complex viscosity-frequency behavior of the PMIA/[Bmim]Cl solutions is similar to that steady-state rheological behavior. The different rheological behavior shows the interaction between macromolecule and IL which leading the supermolecular aggregates in PMIA/[Bmim]Cl solution.The reason of special rheological behavior is attributed to the high shear rates destroyed the hydrogen-bond between PMIA and[BMIM]C1.The wet-spinning formation of PMIA/RTILs concentrated solutions has been performed on self-constructed spinning equipment.The factors that effect the properties of PMIA fiber have been studied.The result shows that the properties of PMIA fiber increase with increasing concentration of PMIA in the solution.In this paper,the PMIA fiber could posses the best properties when the conditions like these:the concentration of spinning solution is 18wt%,the temperature of spinning solution is 90℃,H₂O is used as coagulating bath,the temperature of coagulating bath is 40℃.The structure and properties of PMIA fiber were studied by SEM,TGA etc,the result shows that the thermal properties of PMIA fiber are better than Nomex fiber.Results show that some RTILs are good solvents for PMIA.It is believed that the application of RTILs as solvents of PMIA will solve the pollution problem in PMIA industry and widen the application of PMIA.更多还原