【作者】 马玉春；

【导师】 张留成；

【作者基本信息】 河北工业大学 ， 材料学， 2008， 博士

【摘要】 双马来酰亚胺树脂以其优异的耐热性、电绝缘性、耐辐射、阻燃性、耐侯性,良好的力学性能和尺寸稳定性,成型工艺类似于环氧树脂等特点,被广泛应用于航空、航天、机械、电子等工业领域中。本文采用双马来酰亚胺改性甲基丙烯酸甲酯、环氧树脂和不饱和聚酯树脂,以期提高这三种材料的耐热性能和机械性能,从而拓宽聚甲基丙烯酸甲酯、环氧树脂和不饱和聚酯树脂的应用范围,所以这一课题的研究具有重要的理论和实际意义。本文合成了一种含有双酚S基团的液晶双马来酰亚胺(用Ia表示)、一种含芳酯键的液晶双马来酰亚胺(MBMI)和一种芳醚砜双马来酰亚胺(即SEM),分别应用FT-IR、1H NMR、DSC、HSPM对其结构和液晶行为进行了表征与分析。结果表明,合成了预期产物,Ia和SEM都具有向列相的球粒织构,而MBMI具有纹影织构,但都呈现较好的热致液晶行为。所合成的含有双酚S基团的液晶双马来酰亚胺尚少见文献报道,这是本论文的一个重要创新点。目前有关甲基丙烯酸甲酯耐热改性的研究工作报道较多的是使用N-环己基马来酰亚胺,本文则系统研究了使用芳醚砜双马来酰亚胺和二苯甲烷型双马来酰亚胺改性甲基丙烯酸甲酯,即研究了MMA–SEM二元共聚物体系和MMA–BMD二元共聚物体系的单体配比对共聚物的热学性能及力学性能的影响。结果表明,改性后的PMMA有较好的耐热性,同时对力学性能影响不大,这也是本文的另一创新点。双马来酰亚胺由于结构的特点,使得双马来酰亚胺树脂具有熔点高、溶解性差、成型温度高、固化物脆性大等缺点,这些均限制了双马来酰亚胺树脂的应用与发展。为改善双马来酰亚胺的这些缺点,采用4,4,/—二氨基二苯醚(DDE)作为改性剂对二苯甲烷型双马来酰亚胺(BMD)和液晶双马来酰亚胺(Ia)进行了扩链改性,并对其结构和液晶行为进行了表征。结果表明DDE的引入并没有改变Ia的液晶性,这对于制备实用的液晶聚合物网络具有重要价值。本文采用二苯甲烷型双马来酰亚胺单体(BMD)、液晶双马来酰亚胺单体(Ia)及其各自的扩链齐聚物,改性环氧树脂E-51/芳香胺固化体系。结果发现双马来酰亚胺和其扩链齐聚物对改善环氧树脂的韧性和耐热性具有较好的作用。而液晶双马来酰亚胺及其扩链齐聚物对改善环氧树脂的韧性效果更明显。这可能是由于固化体系的交联密度和交联点刚性改变的缘故。采用二苯甲烷型双马来酰亚胺和液晶双马来酰亚胺及其各自的扩链齐聚物对不饱和聚酯进行了改性,并与纯不饱和聚酯树脂进行性能对比。BMD和Ιa对提高复合材料的强度和耐热性效果均较好,Ia因含有刚性基团使复合材料的耐热性提高更多。二苯甲烷型双马来酰亚胺齐聚物对材料的拉伸强度改性效果较明显,尤其在齐聚物的加入量为1%时比纯不饱和聚酯的拉伸强度提高了近26%。液晶双马来酰亚胺齐聚物的加入使复合材料的拉伸强度、冲击韧性、弯曲强度都有所提高,尤其是在双马来酰亚胺/二胺基二苯醚加入量为0.5%时,力学性能最好。本文采用非等温DSC分析法分别对液晶双马来酰亚胺单体改性环氧树脂体系、不饱和聚酯树脂体系和液晶双马来酰亚胺齐聚物改性环氧树脂体系和不饱和聚酯树脂体系进行了固化动力学的研究,求得了固化反应的表观活化能、固化反应级数、凝胶温度和固化温度等动力学参数,并得到了固化反应表观活化能随固化度的变化而变化的关系。更多还原

【Abstract】 The bismaleimide resins are widespreadly used in the areas of aviation, airspace, mechanical and electronic industries because of their features such as thermal stability, insulativity, radioresistance, fire retardatory property, weather resisting property, good mechanical property and dimensional stability. In this work, methyl methacrylate(MMA), epoxy resin(EP) and unsaturated polyester resin(UP) were modified by industrial bismaleimides(BMD) and liquid crystalline bismaleimides to increase the thermal stability and mechanical property of the three materials. So the ranges of the three materials useness will be enlarged. The work has an important theoretical and practical senses.In this paper, a liquid crystal bismaleimide containing bisphenol-S group(Ia) and a bis[4-(4-maleimidophenoxy) phenyl]sulfone(SEM) have been synthesized and characterized by FT-IR, 1H NMR、DSC、HSPM. The spherulitic texture of nematic phase and good nematic liquid crystalline behavior can be observed by HSPM. Since Ia hasn’t reported, this is the article′s innovation.Now most of the studies about modifying MMA thermal stability used N-cyclohexyl maleimide. In the paper, MMA was modified by SEM and BMD. The SEM-MMA binary copolymers and BMD-MMA binary copolymers in different ratios were prepared by bulk copolymerization. The results showed that the thermal properties of copolymers increased and the mechanical properties of these copolymers are the same as that of pure PMMA, which is the article’s another innovation.The bismaleimide has the defects such as high melting point, bad resolvability, high curing temperature, great brittleness because of the structure, and these restrict its application and development. Industrial bismaleimides copolymers (BMDE) and liquid crystalline bismaleimide copolymers (IaE) are synthesized by using 4,4′-diaminodiphenyl ether (DDE) as chain extending reactants to improve some properties. The structure and liquid crystalline behavior are characterized by FT-IR and HSPM. The introduction of DDE has no effect on the liquid crystal behavior of Ia.The curing systems of E-51/amine modified by BMD, BMDE, Ia and IaE are studied. It is found that BMD and BMDE can improve the materials’impact strength and thermal properties. Compared with BMD and BMDE, Ia and IaE shows some advantages in the aspect of toughness, which may be attributed to special characters of liquid crystalline. The changes of materials’properties may be due to the change of the system’s crosslink density and the chain rigidity between the crosslinked points.The thermosetting bismaleimide (BMD, Ia) and oligomers(BMDE, IaE) as a second component are introduced to unsaturated polyester resin respectively. It is found that BMD and Ia can improve the materials’strength and thermal properties, but Ia-UP system show some advantages in the aspect of thermal properties because of Ia’s chain rigidity. BMDE can improve the materials’tensile strength obviously, and the tensile strength of BMDE-UP systems is improved 26% when the content of BMDE is 1%. IaE can improve the materials’tensile strength, impact toughness, bend strength. The mechanical properties are the best when the content of IaE is 0.5%.The non-isothermal curing kinetics of Ia-EP, IaE-EP, Ia-UPand IaE-UP are studied with DSC. The reaction heats and degrees of curing at different heating rates are evaluated. The reaction heats at different heating rates are close to a constant. The kinetic parameters, i.e. apparent activation energy Ea and reaction order n are presented based on Kinssinger and Crane equations. Apparent activation energy Ea as a function of curing degreeαis more than the constant activation nenergy.更多还原