【作者】 张开闩；

【导师】 陈一民；

【作者基本信息】 国防科学技术大学 ， 高分子化学与物理， 2007， 硕士

【摘要】 聚酰亚胺是一类含有亚胺环的芳杂环聚合物,具有卓越的热力学性能,在高温环境中其性能优势更为明显。近四十年来,聚酰亚胺材料在许多高性能领域得到了迅速的发展和应用,如航空和微电子领域。聚甲基丙烯酰亚胺(PMI)是其中发展较快的一种,在具有聚酰亚胺材料优异性能的同时,具有良好的可加工性。本文利用甲基丙烯腈(MAN)和甲基丙烯酸(MAA)的共聚反应,制备了MAN-MAA共聚物,并经过酰亚胺环化反应制得聚甲基丙烯酰亚胺(PMI);同时,为了提高PMI的性能,采用原位插层聚合制备了PMI/MMT纳米复合材料。利用FT-IR、DSC-TGA、SEM及力学性能测试等手段,分析表征了材料的结构与性能。首先,以溶液聚合和本体聚合,制备了MAN-MAA共聚物,研究了反应温度、原料配比和引发体系对聚合过程的影响,通过对共聚物热性能和力学性能的分析表征,确定了适当的聚合方法,相应的反应体系组成和聚合工艺条件;并研究了环化反应的机理,通过控制环化时间和环化温度及PMI的性能研究,确定了共聚物的最佳环化工艺条件。采用悬浮聚合制备了高分子量聚甲基丙烯酸甲酯(PMMA),研究了分散剂、反应温度和时间等对PMMA分子量的影响;将高分子量PMMA用于反应体系的增粘,有效解决了纳米蒙脱土在反应液中的沉降问题及其在共聚物中均匀分散的问题。对PMI/MMT纳米复合材料的结构和热力学性能研究的结果表明,所制备的PMI/MMT纳米复合材料中纳米MMT分散均匀,与纯PMI比较,其玻璃化转变温度由213℃提高到220℃,弯曲强度由51MPa提高到135MPa。此外,本文还探索制备了AN-MAA共聚物/MMT纳米复合材料,并将AN-MAA共聚物环化后的产物称为半-聚甲基丙烯酰亚胺(半-PMI),与PMI/MMT纳米复合材料比较,半-PMI/MMT纳米复合材料的玻璃化转变温度略有下降,弯曲强度降低20%。更多还原

【Abstract】 For recent 40 years, polyimides have been developed rapidly and applied in manyhigh performance fields, such as aerospace, microelectronics, and so on.Polyimide exhibitted outstanding thermal and mechanical properties, especially at elevated temperature.Polymethacrylimide(PMI) was a type developed rather rapidly among polyimides, good process ability was gained besides keeping function advantage.In this thesis, MAN-MAA copolymer was prepared by copolymerization of methacrylic acid(MAA) and methacrylonitrile(MAN), PMI was formed via the imidation(cyclization, i.e.) of the copolymer to polyimide.PMI/montmorillorite nanocomposite was prepared by in-situ intercalate polymerization to enhance the properties of PMI afterwards.The stucture and property of the material mentioned above were characterized by FT-IR、DSC-TGA and SEM.The work was composed in following parts:First of all, MAN-MAA copolymer were synthesized by solution polymerization and bulk polymerization, parameters such as reaction temperature, monomer ratio and initiator were investigated in polymerization.The preferable condition of polymerization was gained by characterization of thermal and mechanical properties.The mechanism of cyclization was studied at the mean time, and the preferable cyclization condition of the MAN-MAA copolymer was acquired via the controlling of time and temperature.For the sake of nano MMT’s homogeneous dispersion , high macromolecule poly(Methyl-Methacrylate) was synthesized via suspension polymerization, the influences of temperature, concentration of initiator, and conversion rate on molecular weight were analysed. In this way, the viscosity of the monomer reaction solution was improved.Based on the above work, influence of nano MMT to the property the copolymer was studied. Thanks to this special structure, the thermal and mechanical properties of the nano composite formed by PMI and MMT taken on a great improvement comparing to PMI.Furthermore, nano composite prepared by Acrylonitrile-Methacrylic acid(AN-MAA) copolymer/MMT was produced , after the same cyclization procedure as the methacrylonitrile-methacrylic acid copolymer, a structure named half-PMI was formed, compared to PMI/MMT nano composite , the glass-transition temperature of the half-PMI/MMT nano composite descended little, the bending intensity of the former descended 20%.更多还原