【作者】 金欣；

【导师】 崔益华；

【作者基本信息】 南京航空航天大学 ， 材料学， 2010， 硕士

【摘要】 聚对苯二甲酸乙二醇酯（PET）具有优良的耐热性、耐化学药品性、电绝缘性和易回收利用等特点,主要应用于合成纤维和工程塑料等领域。PET的主要缺点是结晶速率慢、冲击强度低、耐磨性差。为了实现PET的高性能化,使之能应用于滑块、齿轮和滑动轴承等耐磨构件,替代部分无法回收的工程塑料和易受化学腐蚀失效的金属,需要对其进行功能改性。本文采用高速剪切法对纳米Al₂O₃进行分散处理,同时对其表面进行包覆处理和偶联改性,通过原位聚合法成功制备了纳米Al₂O₃/PET复合材料,并对其进行了性能测试和表征。红外光谱分析表明,经包覆处理和偶联改性的纳米Al₂O₃表面分别存在PEG和KH-560的特征基团;TEM分析表明,未处理的纳米Al₂O₃自团聚现象严重,而经改性处理的纳米Al₂O₃在乙二醇（EG）和PET基体中分散均匀,平均粒径在30⁸0nm之间;XRD和DSC分析表明,纳米Al₂O₃在PET结晶过程中起到了异相成核的作用,显著促进了PET的结晶。力学性能测试表明,经包覆处理和偶联改性的纳米Al₂O₃/PET复合材料的冲击韧性有了较大提高,同时拉伸强度基本不变;摩擦磨损测试表明,在干摩擦滑动条件下,当纳米Al₂O₃的含量为1.6%时,经PEG和KH-560表面处理的纳米Al₂O₃/PET复合材料均表现出较低的磨损率,与未处理的纳米Al₂O₃/PET复合材料相比分别降低了51%和70%,较纯PET分别降低了68%和81%;SEM分析表明,随着改性纳米Al₂O₃的加入,复合材料的冲击断面形貌出现了韧窝和撕裂带,断裂形式由脆性断裂向着韧性断裂转化;复合材料的摩擦表面犁沟逐渐变浅,且塑性变形程度降低,表面较为平整,磨损机制为轻微的粘着磨损。更多还原

【Abstract】 Polyethylene terephthalate （PET） is mainly used in the areas of synthetic fibers, packaging materials and engineering plastics possesses because of its excellent heat resistance, chemical resistance, electrical insulation and easy recycling. The disadvantages of PET include its low crystallization rate, low impact strength and poor abrasion resistance. In order to achieve high performance and to be used as the slider, gear and sliding bearings to replace some thermosetting engineering plastics and corrosive metal materials, the functional modification of PET has been an important research topic in recent years.In this paper, nano-Al₂O₃ particles were dispersed in EG solvent during the process of high-speed shearing and were simultaneously chemically treated by polyethylene glycol and silane coupling agent respectively, then they were used to prepare nano-Al₂O₃/PET composites by in-situ polymerization. Finally the properties of composite materials were tested and analyzed. The IR analysis indicated that on the surface of treated nano-Al₂O₃ particles there were characteristics groups of PEG and KH-560. TEM analysis showed that the untreated nano-Al₂O₃ got agglomerated seriously, while the treated nano-Al₂O₃ were dispersed uniformly in the EG solvent and PET matrix with an average diameter of 30⁸0nm. XRD and DSC analysis showed that nano-Al₂O₃ played a heterogeneous nucleation role in the PET crystallization process.Mechanical tests showed the impact strength of treated nano-Al₂O₃/PET composites was obvioulsly improved, while there was no decrease in the tensile strength. The friction and wear tests showed that in the dry friction condition, when the weight fraction of PEG and KH-560 treated nano-Al₂O₃ was 1.6%, the composites showed a lower wear rate, which were decreased by 51% and 70% respectively, compared with the untreated nano-Al₂O₃/PET composites, and were decreased by 68% and 81% than that of the PET. SEM analysis showed that with the increasing of the weight fraction of the treated nano-Al₂O₃, some dimples and tear occurs zone appeared on the impact fracture morphology of the composite materials, indicating the characteristic of toughness fracture. There were furrow shallow and slight plastic deformation on the friction surface, which showed the mild adhesive wear behavior.更多还原