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石墨烯自2004年发现以来,由于其独一无二的优异性迅速成为科学家们的研究热点.由于石墨烯具有极其优异的电学、力学和热学等性能,因此被广泛应用于高性能聚合物基复合材料的制备.众所周知,纳米填料在聚合物中的分散状态以及与基体间的界面作用是构筑高性能聚合物纳米复合材料的关键因素.由于石墨烯极易团聚,难以通过传统的熔融共混法制备均匀分散的石墨烯增强-聚烯烃纳米复合材料.另一方面,聚烯烃通常需要在较高温度下才能溶于部分有毒溶剂(如:三氯苯和二甲苯等),因此溶液共混法也不适用于聚烯烃-石墨烯纳米复合材料的制备.有鉴于此,本文开发了一种共沉积法制备石墨烯/二氯化镁负载钛系齐格勒-纳塔催化剂的路线.通过原位聚合直接制备出石墨烯均匀分散的聚烯烃/石墨烯纳米复合材料.考察了石墨烯的加入量对催化剂形态及其催化乙烯聚合行为的影响.当石墨烯加入量较低时,多个石墨烯片被包裹于较大的催化剂粒子中.随着石墨烯加入量的增加,催化剂趋向于在石墨烯表面聚集.继续增加石墨烯量将导致石墨烯包裹催化剂粒子,降低过渡金属钛的负载效率.通过三乙基铝活化后,所制备的催化剂具有非常高的乙烯催化活性,所生成的聚乙烯/石墨烯纳米复合材料复制了催化剂的片状结构.同时,通过对所制备的聚乙烯/石墨烯纳米复合材料进行电子显微镜和X射线衍射分析可知,石墨烯均匀分散于聚乙烯基体中,并且没有任何团聚现象发生.该复合材料的热重分析表明,仅加入非常少量的石墨烯就可以使其具有比纯聚乙烯更高的热稳定性,当石墨烯加入量为0.66 wt%时,其5 wt%热分解温度较纯聚乙烯升高了54℃.同时,所制备聚乙烯/石墨烯纳米复合材料具有更优异的机械性能.因此,本研究提供了一个简单高效的高性能聚烯烃/石墨烯纳米复合材料的制备方法.
Graphene has quickly become a research hotspot for scientists due to its unique excellence since its discovery in 2004. Due to its excellent electrical, mechanical and thermal properties, graphene is widely used in high-performance polymer-based composites Preparation.It is well known that the dispersion state of nano-filler in the polymer and the interface with the matrix is the key factor to build high performance polymer nanocomposites.It is difficult to prepare uniform graphene by the traditional melt blending method Dispersed Graphene Reinforced Polyolefin Nanocomposites On the other hand, polyolefins usually need to be soluble in some of the toxic solvents (eg, trichlorobenzene and xylene, etc.) at higher temperatures, so the solution blending method does not Which is suitable for the preparation of polyolefin-graphene nanocomposites.In view of this, a route of coprecipitation for preparing graphene / magnesium dichloride supported Ti-Ziegler-Natta catalyst has been developed.After direct preparation by in-situ polymerization Graphene dispersed uniformly grafted polyolefin / graphene nanocomposites investigated graphene added amount of catalyst morphology and its catalytic ethylene The behavior of the composite.When the graphene is added in a small amount, a plurality of graphene sheets are wrapped in larger catalyst particles.As the amount of graphene added, the catalyst tends to aggregate on the surface of the graphene.Continuous increase of graphite The amount of ethylene will lead to graphene encapsulation of catalyst particles, reducing the loading efficiency of titanium transition metal.Through the activation of triethyl aluminum, the prepared catalyst has a very high ethylene catalytic activity, the resulting polyethylene / graphene nanocomposite replication The catalyst sheet structure.At the same time, the prepared polyethylene / graphene nanocomposites by electron microscopy and X-ray diffraction analysis shows that graphene dispersed uniformly in the polyethylene matrix, and no agglomeration phenomenon. Thermogravimetric analysis of the composites showed that only adding a very small amount of graphene can make it have a higher thermal stability than pure polyethylene, when the amount of graphene added is 0.66 wt%, its 5 wt% thermal decomposition temperature is Pure polyethylene increased by 54 ° C. At the same time, the prepared polyethylene / graphene nanocomposites have more excellent mechanical properties.Therefore, this study provides a simple and efficient Preparation of composite material properties of the polyolefin / graphene nano.