【作者】 宋晓雷；

【导师】 胡祖明；

【作者基本信息】 东华大学 ， 材料科学与工程， 2008， 硕士

【摘要】 本文首先介绍了PPTA纤维的发展概况,对纤维的性能特点、表面改性、复合材料及应用等方面的研究现状进行了综述。在此基础上,从三个方面对PPTA纤维的表面改性进行了研究。研究了用磷酸处理PPTA纤维表面的效果。对实验条件进行了正交设计,并采用单丝断裂强度、红外光谱、扫描电镜、接触角实验分别表征了纤维强度、表面官能团、微观表面形貌、浸润性的变化。结果表明磷酸处理提高了纤维表面的极性,改善了纤维与树脂复合的界面。并对反应的机理进行了推测。通过对实验结果的方差分析发现:温度对纤维浸润性的影响显著,浓度和时间对浸润性的影响不大;而就强度而言,浓度和时间对纤维的强度的影响显著,温度对纤维强度的影响不显著。因此为了获得最好的浸润性和最好的强度,确立最佳改性条件为:用5%磷酸在55℃下,超声处理1h。研究了先用磷酸处理,然后进一步用稀土溶液处理纤维表面的效果。结果表明,稀土的进一步处理对纤维的强度几乎无损伤。而处理后纤维的浸润性得到进一步的提高。另外,从纤维和环氧树脂复合材料的劈裂面来看,处理后的纤维表面粘有更多的树脂,纤维与树脂之间的界面模糊,且有大量丝状剥离,同时纤维本身也发生微纤化轴向劈裂破坏,说明处理后的纤维与树脂形成了良好的界面。通过对纤维与树脂界面剪切强度的测试,发现其剪切强度随着稀土浓度的增加,出现先增大后减小的趋势,用0.9%的稀土溶液处理后的纤维得到的界面剪切强度最大。另外,用PPTA浆粕取代石棉为增强基,酚醛树脂为基体制成耐摩擦复合材料。结果表明PPTA浆粕制得的复合材料的高温耐磨性能明显高于石棉。用磷酸处理和磷酸/稀土综合处理后的PPTA浆粕制得的复合材料的高温耐磨性能得到进一步改善。最后还对制得的复合材料的冲击强度进行了初步研究。更多还原

【Abstract】 In this paper, progresses and developments of PPTA fiber were reviewed, the properties of it were introduced, and the surface modifications, applications and composites of it were reviewed. On the basic of these, the surface modification of PPTA fibers was studied.Firstly, PPTA fibers were treated with H₃PO₄ solution. Fourier Transform Spectrum （FTIR） was employed to character the change of the fiber; scanning electromicrograph （SEM）, contact angle test were employed to research the changes of the surface properties of the fibers. And single fiber strength experiment was used to show the strength loss because of the treatments. All the results showed that H₃PO₄ solution could improve the surface properties of PPTA fibers efficiently with little strength loss. The orthogonal design was used to find the best technical condition. It showed that the best treated condition was to treat the PPTA fibers with 5% H₃PO₄ solution at 55℃for 1 h.Secondly, PPTA fibers that treated with H₃PO₄ solution at 55℃for 1 h was treated with LaCl₃ solution further. It showed that the rare earth treatment did no harm to the fiber strength while the wettability of fiber was improved. The SEM photo of the fracture surface of PPTA/epoxy composites showed that the surface of untreated fibers was smooth, and little epoxy resin was adhered to the surface. However, for the PPTA fiber treated with rare earth solution, a large amount of epoxy adhered to its surface and formed a thick layer. This fact meant that rare earth treatment improve PPTA fiber surface properties effectively. IFSS experiment was employed to study the relationship between the concentration of the rare earth solution and the surface prosperities. It showed the best technical condition was to treat the PPTA fibers with 0.9% rare earth solution.Additionally, PPTA-pulp was used as reinforcement in phenol formaldehyde resin friction slice. PPTA-Pulp showed great advantage over asbestos especially at high temperature. The friction property of PPTA pulp treated by H₃PO₄ or H₃PO₄/rare earth solution was better than the untreated one. The impact strength of the composite was measured. It showed that the impact strength of treated one was better than the untreated one.更多还原