【作者】 陈莹；

【导师】 李耀刚；

【作者基本信息】 东华大学 ， 纳米纤维及杂化材料， 2012， 硕士

【摘要】 热塑性聚氨酯(TPU)硬度高且富有弹性,具有良好的耐油性、耐臭氧性,以及优异的低温性能,因而应用广泛。但是由于其强度不高,耐热性差,易燃,并且在高温下容易发生软化、分解,使机械性能急剧下降,一般情况下它的长期使用温度不能超过80℃,短期使用温度不能超过120℃,这大大限制了它的应用范围。如何在提高TPU耐热性能的同时,保证其综合性能不下降或不发生改变,是多年来人们对TPU性能研究的一个重点。无机材料普遍具有高熔点、高硬度、耐磨损、耐腐蚀和良好的抗氧化性等特点。此外,无机纳米粒子具有独特的光、电、磁和化学特性,这为制备高性能、多功能复合材料指明了新的方向。近年来,无机粒子改性成为TPU改性的主要手段之一。本文选取了三种不同的无机粒子,采用溶液共混法制备了三种TPU/无机粒子功能复合材料,在提高TPU材料耐热性和机械性能的同时,还改善了其阻燃性能和磁性能。首次将硅烷偶联剂改性的硅藻土颗粒填充到TPU材料中,利用硅藻土颗粒的天然孔状结构,将TPU基体吸收到空隙和表面而不能向外迁移,形成一种内部机械啮合的结构,从而使得TPU与硅藻土之间的结合更为牢固。采用傅里叶红外变换光谱(FTIR)、热失重分析仪(TGA)、扫描电子显微镜(SEM)、电子万能试验机、动态力学分析仪(DMA)对复合材料进行表征。结果表明：TPU/硅藻土复合材料的力学性能和耐热性明显提高,其中复合材料的拉伸强度增幅达到62.2%。以表面偶联化处理后的氢氧化镁(MH)为改性剂,采用溶液共混法制备了TPU/MH复合材料。通过FTIR、场发射扫描电子显微镜(FE-SEM)、TGA、电子万能试验机、DMA、ATS 1004050型氧指数仪对复合材料进行表征。结果表明：TPU/MH复合材料的力学性能和耐热性明显提高,当材料的热失重质量分数达到30%时,TPU/MH复合材料的热分解温度较纯TPU提高了58℃。此外,MH的添加提高了TPU复合材料的阻燃性能,随着MH含量的增加,TPU/MH复合材料的极限氧指数值(LOI)从20.5%提高至22.7%。首次采用醇热法制备得到了晶相纯、磁性优良的钴锌铁氧体包覆碳纳米管的复合材料,研究了不同化学计量的钴锌铁氧体纳米颗粒包覆MWCNTs纳米复合材料的磁性能。通过溶液共混法将制得的MWCNTs/Co0.5Zn0.5Fe2O4磁性纳米颗粒添加到TPU材料中,以改善TPU材料的力学性能和耐热性,并赋予材料新的磁响应性能。通过X射线衍射仪(XRD)、透射电子显微镜(TEM)和振动磁强计(VSM)、FE-SEM、TGA、电子万能试验机、DMA对复合材料进行表征。结果表明：MWCNTs/Co1-xZnxFe2O4磁性纳米复合材料的饱和磁化强度随Zn2+含量的增加,呈先递增后下降的趋势,当x=0.5时达到最大值57.5emu·g-1。该复合材料的磁感应灵敏度强,是一种很好的软磁材料。TPU/MWCNTs/Co0.5Zn0.5Fe2O4纳米复合材料的力学性能、耐热性和磁性能明显提高,复合材料的饱和磁化强度高达30.30 emu·g-1。更多还原

【Abstract】 Thermoplastic polyurethane (TPU) has wide applications owing to its excellent performances such as high hardness and resilience, good oil resistance, ozone resistance and outstanding low temperature performance. However, TPU is easy to be softened and decomposed at high temperatures, which leads to the sharp decline in mechanical properties. In general, its long-term using temperature can not exceed 80℃, and short-term using temperature can not exceed 120℃, which greatly limits its scope of application. How to improve the heat-resistant property of TPU, meanwhile ensure the comprehensive performance remain at its original level, is the key point in the research of TPU. As we all know, inorganic materials have many characteristics, for example, high melting point and hardness, good wear resistance, corrosion resistance and oxidation resistance, etc. In addition, the inorganic nanoparticles with unique optical, electrical, magnetic and chemical properties, which opened up a new way for the preparation of high-performance and multi-functional composites. In recent years, the modification of TPU by using inorganic particles as reinforcement is becoming a primary method. In this paper, three different kinds of inorganic particles were selected for preparing three kinds of TPU functional composites by solution blending. The heat resistances, mechanical, flame retardant and magnetic properties of TPU were greatly improved.In this thesis, porous diatomite was used as filler of TPU for the first time. The TPU molecular chains are forced around the pores of diatomite to form a mechanical interlocking structure. which can improve bonding between filler particles and the TPU. Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), electronic universal testing machine, dynamic mechanical analyzer (DMA) were used to characterize these composites. Results indicated that the mechanical properties and heat resistance of TPU/diatomite composites were significantly improved. The tensile strength of the composites was increased by 62.2%.The surface of magnesium hydroxide (MH) particles were modified with 3-methacryloxypropyltrimethoxysilane (y-MPS). And the TPU/MH composites were synthesized by solution blending. FTIR, field emissiom scanning electron microscopy (FE-SEM), TGA, electronic universal testing machine. DMA, oxygen index test instrument were used to characterize these composites. Results indicated that the mechanical properties and heat resistance of TPU/MH composites were significantly improved. The thermal decomposition temperature of the composites was increased 59℃for 30% mass loss. And the Limited Oxygen Index (LOI) values of TPU/MH composites were improved from 20.5% to 22.7%.A magnetic multi-walled carbon nanotubes-based (MWCNTs-based) composite, MWCNTs/Co1-xZnxFe2O4, was synthesized via a facile solvothermal approach. And the TPU/Co0.5Zn0.5Fe2O4 nanocomposites were synthesized by solution blending. X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), FE-SEM, TGA, electronic universal testing machine, DMA were used to characterize these composites. The results showed that the saturation magnetization of the MWCNTs/Co1-xZnxFe2O4 magnetic nanocomposites increased with x when the Zn2+ content was less than 0.5, but decreased rapidly when the Zn2+ content was more than 0.5. The saturation magnetization as a function of Zn2+ substitution reached a maximum value of 57.5 emu·g-1 for x=0.5. The mechanical property, heat resistance and magnetic property of TPU/MWCNTs/Co0.5Zn0.5Fe2O4 nanocomposites were significantly improved. And the saturation magnetizations of TPU/MWCNTs/Co0.5Zn0.5Fe2O4 nanocomposites was increased by 30.30 emu·g-1.更多还原