界面处理对材料导热性能影响的研究

发布时间：2018-10-29 20:10

【摘要】：随着科学技术的飞速发展,传统导热材料已不再适用于现代化工业产生需求。聚合物基高导热材料因具有较高的导热性能、良好的物理化学性能以及经济性等优势,在各领域特别是电子行业表现出广阔的应用前景。但聚合物基体的导热性能一般较差,目前提高该类材料导热性能主要有三种方法:提高聚合物基体的导热性能、在基体中填充具有高热导率的填料以及改善基体与填料之间的界面结合状态。本文主要从改善聚合物基导热复合材料填料与聚合物基体的界面出发,采用两种表面处理方法对填料进行处理。第一种为偶联剂处理以增加填料表面的亲油性,改善填料与聚合物基体的相容性。本文选取KH-550、KH-560和KH-570对填料进行处理,研究了处理溶液的p H值、偶联剂用量及偶联剂水解时间对填料处理效果的影响。当溶液p H为5,偶联剂用量为填料质量分数的1.5%,水解时间为2 h时,填料与水之间的润湿角显著增加,所制备复合材料的热导率最大。经对比发现,采用KH-560对填料进行处理的效果最优。第二种方法为采用溶胶凝胶法,在填料表面包覆氧化锌,制备核-壳结构,并研究了包覆浓度及煅烧温度对填料处理效果的影响。当包覆浓度为1:5,煅烧温度为800oC时,氧化锌完全包覆在填料表面。包覆后填料与环氧树脂的润湿性得到改善,所制备复合材料的热导率也得到了显著提升。但与偶联剂处理不同,虽然包覆氧化锌一定程度上会改善填料与基体之间的润湿性,但复合材料热导率的增加主要是因为在材料中引入了具有更好导热性能的组分。最后,对两种方法处理所制备的导热复合材料采用XRD、热膨胀、动态力学性能及导热性能进行测试。填料发生的晶格畸变、导热复合材料热膨胀系数的降低以及复合材料储能模量及损耗模量的增加均表明填料与聚合物基体之间的界面结合得到了改善,但改善程度并不相同。复合材料热导率测试表明,偶联剂处理对提高材料的导热性能效果有限,而在填料表面包覆具有更高热导率的氧化锌,随着填料用量的增加,复合材料热导率将显著得到改善。两种方法之间的差别与它们的机理密切相关。
[Abstract]:With the rapid development of science and technology, traditional thermal conductive materials are no longer suitable for modern industry. Because of its advantages of high thermal conductivity, good physical and chemical properties and economy, polymer based high thermal conductivity materials have broad application prospects in various fields, especially in electronic industry. However, the thermal conductivity of polymer matrix is generally poor. At present, there are three main ways to improve the thermal conductivity of this kind of material: to improve the thermal conductivity of polymer matrix, The filler with high thermal conductivity is filled in the matrix and the interfacial bonding between the matrix and the filler is improved. In this paper, two surface treatment methods are used to improve the interface between polymer matrix and polymer matrix. The first is coupling agent treatment to increase the lipophilicity of filler surface and improve the compatibility between filler and polymer matrix. In this paper, KH-550,KH-560 and KH-570 were selected to treat the filler. The effects of pH value of the treated solution, the amount of coupling agent and the hydrolysis time of the coupling agent on the treatment effect of the filler were studied. When pH of solution is 5, the amount of coupling agent is 1.5 of the mass fraction of filler and the hydrolysis time is 2 h, the wetting angle between filler and water increases significantly, and the thermal conductivity of the composites is the largest. By comparison, it was found that the effect of KH-560 on the treatment of fillers was the best. The second method is to prepare core-shell structure by coating zinc oxide on the surface of filler by sol-gel method. The effects of coating concentration and calcination temperature on the effect of filler treatment are studied. When the coating concentration is 1: 5 and the calcination temperature is 800oC, zinc oxide is completely coated on the filler surface. The wettability of the filler and epoxy resin was improved, and the thermal conductivity of the composites was also improved. However, different from the coupling agent treatment, the wettability between filler and matrix can be improved to some extent by coating with zinc oxide, but the increase of thermal conductivity of composites is mainly due to the introduction of better thermal conductivity components. Finally, the thermal expansion, dynamic mechanical properties and thermal conductivity of the composites prepared by the two methods were tested by XRD, thermal expansion, dynamic mechanical properties and thermal conductivity. The lattice distortion of filler, the decrease of thermal expansion coefficient and the increase of energy storage modulus and loss modulus of composites indicate that the interfacial bonding between filler and polymer matrix has been improved, but the improvement degree is not the same. The results of thermal conductivity test showed that the coupling agent treatment had limited effect on improving the thermal conductivity of the composites, while the thermal conductivity of the composites coated with zinc oxide with higher thermal conductivity on the filler surface would be improved significantly with the increase of filler content. The difference between the two methods is closely related to their mechanism.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

【相似文献】