【作者】 袁桂芳；

【导师】 苏胜培；

【作者基本信息】 湖南师范大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 本文主要研究有机修饰硼粉的制备、表征及其在聚合物基复合材料中的应用。利用苯乙烯(St)与马来酸酐(MAH)的共聚物(SMA)中的酸酐基团、硬脂酸(HSt)中的羧基与硼粉表面的羟基之间的化学反应,分别制备了SMA修饰硼粉和硬脂酸修饰硼粉。利用红外(IR)、透射电镜(TEM)、热重分析(TGA)分别对其化学修饰的价键结构、有机修饰前后的微观形貌和有机修饰硼粉中有机含量进行了表征和测定,利用激光粒径分析仪(Laser Particles Size Analyzer)测试了修饰前后的硼粉的粒径变化。IR结果表明有机修饰的硼粉中硼粉与SMA、硬脂酸之间为化学键连接；TGA结果表明两种有机修饰硼粉中有机物含量为10%左右；TEM结果显示SMA修饰的硼粉前后由团聚态变为单独存在的硼粉颗粒；粒径测试结果显示SMA修饰后硼粉粒径在乙醇溶液中由原来的2.2μm增加到3.7μm,与TEM结果相吻合；溶剂分散性试验和表面能测试结果也证实了修饰后硼粉表面极性由亲水性变为亲油性,在三氯甲烷溶剂中有较好的分散。将未处理的硼粉和SMA修饰的超细硼粉与尼龙6(PA6)进行熔融共混制备了PA6／硼粉复合材料。Molau试验结果表明,用SMA修饰的硼粉与PA6之间存在着一定的化学键合。力学性能测试结果表明：未处理的硼粉与有机修饰硼粉均能改善复合材料的力学性能；添加1%的改性硼粉,复合材料力学性能最优；SEM结果显示SMA修饰的硼粉在PA6中的分散性优于未处理的硼粉。将未处理的硼粉和SMA修饰硼粉与聚碳酸酯(PC)进行熔融共混制备了PC硼粉复合材料。MFR测试结果显示随着有机修饰硼粉含量的增加,MFR大幅增加；TGA结果显示未处理的硼粉和SMA修饰硼粉均能改善复合材料的热稳定性；力学性能测试结果表明添加1%的改性硼粉,复合材料力学性能最优。将未处理的硼粉和HSt修饰的硼粉与聚丙烯(PP)进行熔融共混制备了PP／硼粉复合材料。其复合材料力学性能和热降解性能均有不同程度的提高。与纯PP相比,添加3%的未处理硼粉时,复合材料拉伸强度增加了12%,冲击强度提高了17%,热降解温度T5%升高了26℃；添加3%的HSt修饰硼粉时,复合材料的拉伸强度增加了15%,冲击强度提高了35%,热降解温度T5%升高了20℃；与纯PP相比,含硼复合材料的MFR均有不同程度的下降。更多还原

【Abstract】 The preparation, characterization and properties of organically-modified boron powder and their composites were studied.The surface modification of boron powder with poly (styrene-co-maleic anhydride) (SMA) and stearic acid (HSt) have been achieved through the reactions between the hydroxyl groups on the boron surface and the maleic anhydride groups in SMA or carboxylic acid groups in HSt. These novel organically-modified boron were characterized using IR, TGA, TEM, and laser particle size analyzer. Experimental results from IR analysis indicated that the surface of boron was successfully modified by SMA and HSt, and TGA data analysis indicated that the amount of organic materials on the boron surface was about 10%of the total mass of modified boron. TEM images of SMA-modified boron indicated that the morphology of boron after modification has also been changed from an aggregated form to separated particles. The average particle size of the boron after modification with SMA was significantly increased from 2.7μm to 3.7μm in ethanol, which was obtained from the laser particle size analysis. The solvent dispersion of this modified boron and surface energy were also tested. Experimental results indicated that the modified-boron powder surface has also been changed in polarity from hydrophilic into hydrophobic and formed a well dispersed and stable suspension in chloroform.PA6/boron composites have been prepared by melt blending of PA6 with untreated boron and SMA-modified boron. Molau tests revealed that there was certain linkage between PA6 and SMA-modified boron. MFR study of composites has shown that the MFR values increased with the increasing content of loaded SMA-modified boron. The testing results of mechanical properties have shown that the mechanical properties of PA6/untreated boron and PA6/SMA-modified boron composites are significantly improved. the results show that the comprehensive properties are good when the content of SMA-modified boron is 10%. SEM analysis has shown that SMA-modified boron is well dispersed in PA6 matrix.PC/boron composites have been prepared by melt blending of PA6 with untreated boron powder and SMA-modified boron. The thermal analysis results have indicated that the thermal stability of PC/untreated boron and PC/SMA-modified boron composites has been enhanced. Melt flow rate (MFR) study of composites has been shown that the MFR values increased with the increasing content of loaded modified boron. The testing results of mechanical properties have shown that that the comprehensive properties are good when the content of SMA-modified boron is 10%.PP/boron composites have been prepared by melt blending of PP with untreated boron powder and SMA-modified boron. The results suggested that the mechanical properties and thermal stability of composites have been significantly improved. Melt flow rate (MFR) study of composites has been shown that the MFR values decreased with the increasing content of loaded modified boron.更多还原