【作者】 由可锦；

【导师】 黄丽；

【作者基本信息】 北京化工大学 ， 材料科学与工程， 2012， 硕士

【摘要】 为了扩大超高分子量聚乙烯（UHMWPE）的应用范围，对UHMWPE的改性工作成为研究的重点。本文采用硅烷偶联剂改性的纳米SiO₂对超高分子量聚乙烯进行填料填充改性，来提高UHMWPE的耐热性和力学性能。并在此基础上对复合材料进行了热处理和硅烷交联改性的研究。论文研究偶联剂改性的纳米SiO₂对UHMWPE的分子结构、结晶行为的影响，探讨了纳米SiO₂对于UHMWPE耐热性、力学性能提升的机理。并根据改性机理对纳米SiO₂/UHMWPE复合材料进行了热处理和硅烷交联改性的进一步研究。试验结果表明：纳米SiO₂的加入能够增加UHMWPE分子链的相互缠结，使UHMWPE结晶速率加快、结晶度增加、晶粒细化。纳米SiO₂很好的起到了物理缠结点和异相成核剂的作用，提高了UHMWPE的耐热性和力学性能。当纳米SiO₂的含量为5%时，复合材料的综合性能最好，复合材料的维卡软化点由85℃提高到了103℃，拉伸强度由29.8MPa提高到了35MPa。热处理对于纳米SiO₂/UHMWPE复合材料来说是UHMWPE分子链段重排及重结晶的一个过程。热处理能很好的消除内应力和结晶缺陷，提升UHMWPE分子间的缠结和结晶度，材料的耐热性和拉升强度也因此获得一定的提升。采用有机硅烷对纳米SiO₂/UHMWPE复合材料进行交联改性，有机硅烷能够增强纳米SiO2与UHMWPE的相容性，同时实现对UHMWPE的化学交联。经过有机硅烷交联后纳米SiO₂/UHMWPE复合材料的分子链缠结和结晶度增加，有利于复合材料的耐热性和力学性能的提升。当KH570的含量为0.7份时，纳米SiO₂/UHMWPE复合材料的维卡软化点达到101℃，拉伸强度达到38.2MPa。更多还原

【Abstract】 In recent years,the modifications of UHMWPE have received increasingresearch interests.In this study,nanosilica was used as filler to improve the heatresistance and mechanical property of UHMWPE.Then the heating treatmentand organosiloxane-induced cross-linking was also adopted.In the paper,the effect of nanosilica on the molecular structure andcrystallization behavior of UHMWPE was studied in order to determine themodification mechanism.Then heating treatment and organosiloxane-inducedcross-linking was used to treat the nanosilica/UHMWPE composite.The results show that the addation of nanosilica can enhance the chainentanglement,increased the degree of crystallization and crystallization rate.Inthe composite the SiO₂acts as a physical cross-link point and a nucleatingagent.At5wt%nanosilica,the properties of composite reaches theirmaximum.The vicat softening point of composite raise from85℃to103℃,the tensile strength raise from29.8MPa to35MPa. Heating treatment lead to the movement of chain segment andrecrystallization.The processing residual and crystal defects can be minimized.The chain entanglement and the degree of crystallization increased afterheating treatment.The heat resistance and mechanical property ofnano-SiO₂/UHMWPE composite were further improved.Organosiloxane was used to cross-link the nano-SiO₂/UHMWPEcomposite. Organosiloxane also can improve the the interface compatibilitybetween nanosilica and UHMWPE.The heat resistance and mechanicalproperty of composite improved due to the increasing of chain entanglementand the degree of crystallization.At about0.7phr organsiloxane,the vicatsoftening point of nano-SiO₂/UHMWPE composite reaches101℃,the tensilestrength reaches38.2MPa.更多还原