【作者】 张颖；

【导师】 张兴文；

【作者基本信息】 哈尔滨工业大学 ， 物理化学， 2011， 硕士

【摘要】 石英纤维增强磷酸盐基复合材料具有耐高温、抗氧化、良好的加工性的优点,可满足多种功能材料的需求,但磷酸盐基体对石英纤维的腐蚀作用会导致复合材料综合性能降低,尤其在高温条件下此类材料的力学性能下降明显,使其应用范围受到了一定的限制。为了提高磷酸盐基复合材料中石英纤维的增强效果,本文采用仲丁醇铝和带有双键的三种类型硅烷偶联剂为前驱体,通过溶胶-凝胶法合成Al₂O₃-POSS复合溶胶,对石英纤维表面进行涂覆,研究防护膜的抗腐蚀性能及其对复合材料力学性能的影响。本文研究了前驱体种类、溶剂含量、螯合剂、水的加入量等因素对铝溶胶透明度和稳定性的影响,获得了最佳合成工艺条件:按仲丁醇铝:乙酰乙酸乙酯:乙醇:去离子水=1:0.3:30:0.8的摩尔比,将反应物于80℃水浴中回流搅拌5h合成了透明稳定的Al₂O₃溶胶。将硅烷偶联剂水解缩合而得的POSS溶胶与其混合搅拌、老化,得到了均匀的Al₂O₃-POSS复合溶胶体系。通过红外光谱吸收法（FT-IR）对复合溶胶的成键情况进行表征,利用差示扫描量热法（TG-DTA）分析了复合溶胶的热性能,最后用凝胶渗透色谱法（GPC）研究了不同组分对复合溶胶分子量分布的影响,结果表明以Al-O-Si化学键结合的复合溶胶具有良好的热性能及更高的分子聚合度。研究了纤维表面杂化膜的涂覆工艺:利用X射线光电子能谱法（XPS）确定了硫酸酸洗法能较完全除去石英纤维表面的有机物,对成膜后的石英纤维表面进行扫描电子显微镜（SEM）测试,结果表明,在常温及高温条件下Al₂O₃-POSS 30和Al₂O₃-POSS 70两种杂化膜膜层致密、均匀而完整,适合作为石英纤维表面的防护膜材料。研究了不同功能基团的POSS对石英纤维的耐蚀性及复合材料弯曲强度的影响,通过扫描电子显微镜（SEM）分析涂覆膜层的石英纤维常温、高温形貌及酸蚀后的表面形貌,结果表明Al₂O₃-POSS 30和Al₂O₃-POSS 70两组份杂化膜对石英纤维起到明显的防护作用。最后,利用三点弯曲法研究了改性后的石英增强磷酸盐基复合材料的力学性能,验证了杂化膜的涂覆可将复合材料的弯曲强度提高50%以上。更多还原

【Abstract】 Quartz fiber-reinforced phosphate matrix composites can meet the needs of a variety of functional materials for its high temperature endurance, antioxidance and good processability. But the phosphate matrix corrosion of the quartz fiber will result in lower overall performance of the composite materials, particularly in the high temperature. Because mechanical properties of these materials will decrease significantly in the high temperature and this restricts its applications. Therefore, how to improve the effects of the reinforcement becomes the main focus. In this paper, Al₂O₃-POSS composite sol was prepared with Al-butanol and three types of double bonds silane coupling agent as the precursor by sol-gel. And then coated it on the surface of the quartz fiber. At last, properties of the corrosion-resistant protective film and mechanical properties of the composite materials were discussed.In this paper, such factors as the precursor type, the amount of solvent, chelating agents and the amount of added water on the transparency and stability of the aluminum sol were discussed. And the optimum conditions were obtained: with Al-butanol: acetyl ethyl acetate: ethanol: deionized water = 1:0.3:30:0.8 by molar ratio, control reaction temperature at 80℃in water bath. Transparent and stable Al₂O₃ sol was obtained after 5h reflux.Then mixed it with POSS sol and got the uniform Al₂O₃-POSS composite sol. First, the composite sol bond conditions were characterized by infrared absorption spectroscopy （FT-IR）. Then, the thermal properties of the composite sol were analyzed by differential scanning calorimetry （TG-DTA）. Finally, molecular weight distribution of the composite sol were characterized by gel permeation chromatography （GPC）. The results show that the composite sol bonded with Al-O-Si has good thermal performance and higher degree of molecular aggregation.Besides, research on the coating process of the hybrid membrane was carried out. By X-ray photoelectron spectroscopy （XPS）, we determined that washing the Quartz fibers with sulphuric acid could remove the organic surfactants on the surface. By scanning electron microscopy （SEM）, the surface coated with the hybrid membrane was tested.The results showed that at room temperature and high temperature conditions, both Al₂O₃-POSS 30 and Al₂O₃-POSS 70 hybrid membranes are dense, uniform and complete. And they are suitable for quartz fiber surface protective film material.We also did some research on corrosion resistance and flexural strength of composites with different functional groups of the POSS. By scanning electron microscopy （SEM）, surface morphology of the fibers coated with the hybrid membrane was tested at room temperature , high temperature and after etching. The results show that the Al₂O₃-POSS 30 and Al₂O₃-POSS 70 played a significant role in the fiber protection. Finally, mechanical properties of these materials were tested by three-point bending method. The results show that the hybrid membrane coating can improve the flexural strength by more than50%.更多还原