【作者】 郭建；

【导师】 章于川；

【作者基本信息】 安徽大学 ， 高分子化学与物理， 2011， 硕士

【摘要】 聚合物纳米复合材料早在80年代初就已提出来,之后很快便成为人们研究的焦点。聚合物纳米复合材料要实现工业化,可以采用原位聚合的方法,即将纳米粒子或改性纳米粒子添加到聚合物原料中,然后原位聚合合成聚合物纳米复合材料。该法能较好地解决纳米粒子团聚及其与高聚物基体中的相容性与分散问题,制得的纳米复合材料性能优异,并且操作简单。本文中分别将未经表面处理的纳米粉体和用自行设计合成的大分子表面改性剂处理后的纳米粉体加入聚氨酯原料中,应用原位聚合的方法合成了不同的纳米粉体／聚氨酯复合树脂。研究结果表明,纳米Si02粉体在聚氨酯基体内可达到纳米尺度的分散；分别应用不同纳米粉体如纳米Si02、纳米CaCO3,对提高聚氨酯性能或降低其成本均有较为显著的作用。本文具体分为以下三个部分：第一章是绪论。通过文献调研,主要介绍了常用的无机纳米粒子及其表面改性方法,以及纳米粒子在聚氨酯改性中应用的研究现状等,最后提出了本课题的设计思路。第二章是介绍了应用纳米Si02粉体,通过原位聚合的方法合成纳米Si02/聚氨酯复合树脂。首先将一定比例的聚四氢呋喃醚二元醇(PTMEG)、己二酸—乙二醇—丁二醇三元共聚酯二元醇(TPEG)、乙二醇(EG)、N,N-二甲基甲酰胺(DMF)和纳米二氧化硅混合,并用溶剂DMF调节到合适粘度后,用高速剪切机剪切10min左右,再经高压剪切分散机处理,然后置于反应瓶内升温至90℃搅拌,并按比例加入4,4’-二苯基甲烷二异氰酸酯(MDI),后视粘度补加少量MDI。合成的复合树脂用FTIR、GPC、TGA、SEM等进行了表征。结果表明,纳米Si02的加入对聚氨酯分子量的影响不大,MDI和硅羟基发生了化学反应,Si02均匀分散在聚氨酯基体中,经改性后的聚氨酯在力学性能上有较为明显的提高。第三章是大分子改性剂(BA)m-(MMA)n-COOH的合成及应用,即用合成的大分子改性剂再改性纳米碳酸钙,进而填充改性聚氨酯。首先选取甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)为单体,巯基乙酸(Mercaptoacetic acid)为链转移剂,偶氮二异丁腈(AIBN)为引发剂,合成大分子改性剂。实验中将上述药品按一定的配比加入到恒压漏斗中,在2.5h内滴加到盛有适量甲苯的三口烧瓶中,在110℃下保温反应4h。然后改装置为蒸馏装置,最后升温到170℃,除去溶剂与未反应的单体,得到合成产物。应用FTIR. 1H NMR、13C NMR、DSC、TGA和GPC对产物进行了表征,结果表明,合成的产物为数均分子量Mn在3500左右、一端带-COOH的丙烯酸酯类聚合物,其主要的失重在300-400℃,且只有一个Tg。然后用合成的大分子改性剂(BA)m-(MMA)n-COOH包覆纳米CaCO3粉体。FTIR、TGA、粒径分析、接触角及沉降实验等分析表明,纳米CaCO3粒子与大分子改性剂发生了化学键和,改性后的纳米粒子亲水性降低、亲油性增加,在溶剂中团聚也明显减弱。最后将改性纳米CaCO3粒子添加到聚氨酯原料中,采用原位聚合的方法合成了复合树脂。SEM显示,改性纳米CaCO3在聚氨酯基体中分散均匀,拉伸测试表明少量纳米CaCO3的加入能提高聚氨酯的拉伸强度；TGA数据可以看出,纳米CaCO3对树脂的热稳定性影响不大。更多还原

【Abstract】 The concept of polymer nanocomposites was advanced in the early 80s, and soon it become to be the focus of the research. The in-situ polymerization method can be used to achieve the industrialization of polymer nanocomposites. Firstly, nano-particles or modified nano-particles were dispersed into polymer raw materials, and then polymer nanocomposites were prepared via in-situ polymerization. The nanocomposites obtained via in-situ polymerization perform well because of the homogeneous dispersion and good compatibility of nano-particles. Besides, the in-situ polymerization method is effective and simple.In this paper, crude nano-particles and nano-particles modified by macromolecular surface modifier which we designed and synthesized were dispersed by high pressure shearing homogenizer (HPSH) into polymer diols, and then polyurethane nanocomposites were compounded via in-situ polymerization. The research indicated that nano-particles dispersed well in the polyurethane matrix, and played an important role in the increase of the performance as well as the reduction of the cost of polyurethane. There are three chapters constitute the thesis:The first chapter is the introduction which presents the frequently used inorganic nanoparticles, as well as their surface modification methods, and their application in polyurethane modification. Finally, the design of the whole paper is advanced.In the second chapter, nano-silica/polyurethane composites were synthesized via in-situ polymerization. Firstly, poly (tetramethylene ether glycol) (PTMEG) and poly (butylenes adipate glycol) (TPEG) and ethylene glycol (EG) and N, N-Dimethylformamide (DMF) and nano-silica were mixed as a certain proportion. Then the mixture treated by high-speed shearing machine and high pressure shearing homogenizer for 10 minutes respectively was placed in a three-neck flask with 4> 4’-diphenylmethane diisocyanate (MDI), The polymerization of polyurethane was carried out at 90℃under nitrogen atmosphere for 3 h. During the reaction, a small amount of MDI was appended according to the viscosity of the system. The composite resins were studied by FTIR, GPC, TGA and SEM. The result showed that the nano-silica in composites method possess homogenous dispersion, and the addition of nano-silica enhanced the mechanical properties of the composites but not reduce the molecular weights.The third chapter is the synthesis and application of macromolecule surface modifier (BA)m-(MMA)n-COOH. Firstly, the solution consisted of Methyl methacrylate (MMA, monomers), Butyl Acrylate (BA, monomers), Mercaptoacetic acid (2-MA, chain transfer agent) and 2,2’-Azobis (2-methylpropionitrile) (AIBN, radical initiator) in the ratio of 500/500/25/1 was add into toluene within 2.5h at 110℃, then the reaction was carried out for four hours. After that, change the device for the distillation and heated to 170℃to remove the solvent and unreacted monomers. The obtained compound was hydroxyl-terminated polyacrylate copolymers. The structure and thermal stability of copolymers were analyzed by FTIR, 1H NMR,13C NMR, GPC, TGA and DSC. The result indicated that the number-average molecular weight (Mn) of the macromolecule surface modifier which were hydroxyl-terminated was about 3500. The main weight loss of the copolymer which had a Tg was between 300℃and 400℃. Then the macromolecule surface modifier (BA)m-(MMA)n-COOH was used in the surface modification of nano-CaCO3. FTIR and TGA demonstrated that macromolecular modifier bonded covalently with the hydroxide radical on the surface of nano-CaCO3. Size distribution analyzer, sedimentation experiment and TEM were exerted to show that the modified nanoparticles dispersed well in organic solvent without serious agglomeration. Contact angle test investigated that the hydrophile of modified nanoparticles was decreased. Finally, the modified nanopartilces were dispersed into raw materials of polyurethane and nano-CaCO3/polyurethane composites were synthesized via in-situ polymerization. SEM showed that nano-CaCO3 in the nanocomposites was homogenously dispersed in the polyurethane matrix. TGA and tensile strength test indicated that the addition of nano-CaCO3 had no effect on the thermal stability of resins but a small amount of nano-CaCO3 would enhance the tensile strength.更多还原