【作者】 王春璐；

【导师】 林润雄；

【作者基本信息】 青岛科技大学 ， 材料加工工程， 2007， 硕士

【摘要】 聚酰亚胺(PI)是目前耐热性最好的有机材料：其分子中的芳杂环结构所形成的共轭体系、阶梯及半阶梯链结构，使其分子链具有很强的刚性、分子链段自由旋转的能垒高，导致高的玻璃化转变温度、较高的熔点和软化点，可在555℃短期内保持其物理性能，长期使用温度高达300℃以上。PI多采用两步法合成，第一步由二胺和二酐反应生成预聚体—聚酰胺酸(PA)，第二步为聚酰胺酸热或化学亚胺化。另外研究结果表明，预聚体PAA的分子量、分子量分布等因素也将影响聚酰亚胺的综合性能。芳香聚酰亚胺(PI)是一类高性能的聚合物，具有优良的介电、耐热及耐高低温和耐磨等性能，广泛应用于宇航、电子电器工业及膜分离技术等领域。我国从60年代开始进行聚酰亚胺的研发工作，也经历了近30年的时间，在单体生产的数量和品种方面具有一定的水平，但已经工业化的聚酰亚胺的单体种类、生产工艺都与国外存在着较大差异。且聚酰亚胺的模塑料和复合材料国内总体生产量还是很低的，主要用于航空航天和军工领域。与杜邦等公司的产品比较在性能和品种方面还存在一定的差距。近年来，随着高新技术与产业的迅猛发展，耐高温、高稳定性、加工性能优良的聚酰亚胺材料成为先进材料发展的一个重要方向。在聚酰亚胺主链上引入柔性官能团，既可以改善聚合物的成型加工性能，同时又可获得特定的功能性。本论文正是围绕这一课题进行更为深入的研究，通过对二元胺和二元酐单体的选择，进一步系统地研究聚酰亚胺合成与材料制备中的重要化学和物理问题：如结构与性能的关系，不同合成路线对最终产品性能的影响等等。并将性能与同课题组所合成的含氟聚酰亚胺的性能进行对比。在具体的工作中，首先选用含有不同官能团的单体，如含醚二胺、含酮二酐，和含砜基的二胺、二酐，以进行接下来的合成反应。接下来的论文工作可分为2个阶段：第一阶段为不同结构聚酰亚胺的合成，这一阶段又分为三步：第一步为醚酮类聚酰亚胺的合成与测试：将含醚、酮官能团的不同的二胺、二酐通过一步法、两步法、三元共聚法合成了一系列结构不同的聚酰亚胺；第二步为含砜基聚酰亚胺的合成：主要选择了一种含砜基的二胺与含砜基二酐进行缩聚；第三步为酮酐型含砜基类聚酰亚亚胺的合成。第二阶段为对所制得的一系列不同结构的聚酰亚胺通过乌氏粘度计、红外、TGA、DSC、X衍射等方法进行性能测试，并与含氟聚酰亚胺的性能进行对比。结果表明，受主链中占主导作用的刚性基团影响，所制得的醚酮类、含砜基聚酰亚胺的溶解性总体不如含氟聚酰亚胺，但是醚酮类聚酰亚胺的热性能好于含氟聚酰亚胺；对于不同的合成工艺来说，一步法因为在亚胺化的高温状态下仍存在大量溶剂，使得分子链有时间进行规整排列，亚胺化后的分子链具有了较大的刚性，从而具有较高的热性能，两步法次之，三元共聚因为破坏了主链的规整性导致热性能下降；对于不同官能团来说，含有醚、酮官能团的聚酰亚胺的热性能较为理想，而当砜基在其主要结构中起主要作用时可以显著改善聚酰亚胺的溶解性，热性能则有较大下降。酮酐型含砜基类聚合物的热性能介于醚酮类聚酰亚胺与含砜基聚酰亚胺之间。更多还原

【Abstract】 Polyimide has so far the best thermal-performance among organic materials,the phenyl- heterocyclic groups could form conjugated, scalariform and semi-scalariform structure which gives its molecule strong hardness, high free rotatingenergy, and thus lead to high glass transformation temeperature, melting point andintenerate temperature, could retain its physical performance for a short periodunder temperature of 555℃, while under 300~C or even higher its performancecould be kept for a long time. The most developed synthetic route for theseimportant materials is the classical two-step method, the first step being thesynthesis of precursor, ie. poly(amic acid) (PA) from the reaction ofdiamine anddianhydride and the latter step being subsequent thermal or chemical imidizationof the poly(amic acid). Many studys have shown that the molecular weight of PAA,and distribution of molecular weight will affect PI’s performance.Aromatic polyimides (PIs) are one of the most important class ofhigh-performance polymers. Due to their excellent electrical, thermal, and lowand/or high-temperature mechanical properties, PI have a wide range ofapplication in fields such like aeronautics, electrical system, and IT industry andhave played an important role. China started researching into polyimide in 1960s,after 30 Years of development the production of monomer’s qutity as well as itsvariety has reached a certain level, but there’s still a certain gap between foreigncountries in monomer’s category and producing technology, also, the output ofmould plastic as well as composite material is rather low and still mainly used inavigation and war industry field. Certain gap also exists in production variety andperformances when compared with Dupont Company. With the rapid progress intechnology and production, PI with high thermal-resistance, stability, progressingfeasibility has become an novel developing orientation. Introducing soft groups into PI could improve its processing feasibility, also, certain functional propertycould be obtained at the same time.In this work, different kinds of monomers with groups such like aethergroups, katone groups, as well as sulphone groups have been chosen to synthesizepolyimides. The work canbe divided into 2 steps: the 1st step is the synthesis of PIwith different function groups, which has 3 processes: 1) Synthesis of PI withaether and katone groups. Mainly by two-step method, combined.with 1-stepmethod as well as co-condansation; 2) Synthesis of PI with sulphone groupsthrough 2-step method; 3) Synthesis of PI with katone as well as sulphone groupsthrough 2-step method. The 2nd step are characterization of PI. The resultant PIs’properties were tested with techniques such as intrinsic viscosity, IR, TGA, DSC,X-ray and so on. Then their performances are compared with fluorinated PI.The result shows that with the affect of hard groups in molecule, PI withaether and katone groups can obtain a excellent thermal-performance, while theirsolvency are not inproved so well as fluorinated PI. When concerning to thedifferent method in synthesizing, during one-step method there’s still enoughsolvent at a high temperature which allows molecules to arrange in order, thusgives molecules its stiffiaess which lead to a high thermal-performance. PIsynthesised by two-step method has a thermal-performance slightly weaker thanone-step methods. Co-condensation can destroy the inerratic arrangement and thuslead to a decline in thermal-performance. When concerned with different functiongroups, PI with aether and katone groups has a relative better thermal-performance,sulphone group can improved its solvency while sulphone group plays the mainrole, but its thermal-performance declined. PI with heterocyclic groups canimprove solvency much better, with a thermal performance better than PI withsulohone groups while a bit lower than PI with aether-katone PI.更多还原