The Preparation Of Graphene Oxide Derivatives And The Improvement Of Their Thermal Stability

Flame retardant is a kind of important additives. It is developing rapidly towards to Halogen-free and low toxicity. More and more new flame retardant have been developed and put into practical application.Graphene is a two-dimensional honeycomb structure formed by single-layered carbon atoms through the way of sp2hybridization. The special two-dimensional planar structure of graphene meets the requirements of condensed phase mechanism of flame retardant, therefore, graphene has been confirmed can also play a role in the field of flame retardant.The excellent properties of the graphene are also gradually being discovered. Due to its high carrier mobility, large specific surface area, good thermal conductivity and transmission of light and excellent mechanical properties, graphene has been greatly concerned, and in many fields such as electronics, battery, photocatalytic, lots of important results have been achieved.Currently, reduction of exfoliated graphene oxide has been proved to be the utmost proper way to product graghene for laboratory because of its low price and huge quantity. As the precursor of graphene, graphene oxide is the inevitable preparation stage of graphene through oxidation-reduction method. Graphene oxide contains a large amount of oxygen-containing functional groups which not only have good hydrophilicity, but also provide a possibility of surface functionalization modification, such as hydroxyl, carboxyl, epoxy, etc.Graphene oxide also has a good prospect in the field of flame retardant, which is confirmed. But its thermal stability is not satisfactory, limiting its further application. In this paper, in order to improve the material thermal stability, two ways of covalent grafting and hybrid based on graphene oxide are designed, which is expected to be applied in flame retardant materials.The main tasks are as follows:(1) The graphene oxide covalent grafted with melamine was synthesized without any reducing agent, which is confirmed by Fourier transform infrared and X-ray photoelectron spectroscopy. Meanwhile, after modification, the thermogravimetric analysis and differential thermal analysis illustiate that the complete decomposition temperature of graphene oxide raised by nearly100℃while the highest heat release was reduced by85%. There is an obvious improvement in thermal stability as a whole, which contains practical as well as theoretical significance for the development of new graphene-based hybrid materials. (2) Alumina has good thermal stability. Alumina particles were attached on the surface of graphene oxide by the way of hybrid. The hybrid materials were successfully synthesized through the analysis of X-ray diffraction and scanning electron microscope. Thermogravimetric analysis results show that the hybrid material thermal stability is better than that of the graphene oxide. It has a certain application prospect in the field of flame retardant.