Long-Hangzhou Normal soup: graphite oxide has a synergistic flame retardant effect ene reaction of silicone rubber foam assembly
Recently, Hangzhou Normal Organosilicon Chemistry and Materials Technology Laboratory Long-soup groups Successful graphite oxide was prepared having a synergistic effect of flame-retardant silicone rubber ene reaction assembly foam, using two-dimensional silicone rubber material reaction foam, a dense protective layer is formed in situ on the surface of cells, to achieve the mechanical reinforcement and efficient flame retardant material . In research \”In situ reactive self-assembly of a graphene oxide nano-coating in polymer foam materials with synergistic fire shielding properties\” was published in the Journal of Materials Chemistry A (2018 IF: 10.733).
includes both the silicone rubber foam of silicone, high elasticity, flame characteristics, etc. and both the foam is light, heat, etc., has become important structural materials in the field of defense, and other high-iron, nano-modified material is an effective means to enhance its performance. However, physical blends of conventional coating and surface modification methods exist nanofiller agglomeration, adding a high content, the filler / matrix interface is not ideal, it is difficult to control and other bottlenecks structure is difficult to sufficiently exert superior performance nanomaterials.
Based on this, Long-soup and innovative design team developed a simple, green, low cost the reaction self-assembly process, very low levels of the two-dimensional graphene oxide sheets (~ 0.1wt%) is assembled to the silicon surface of the foam cell, between the graphene surface oxidation using an oxygen-containing functional group or a hydroxyl group with hydrogen silicone silicone molecules build a strong chemical reaction with the matrix interfacial effect thin dense protective layer single layer or oligonucleotide, which is not only beneficial to improve the carrying capacity of the foam cellular structure, but also to suppress a high internal silicone moleculesThermal Decomposition, and thus significantly enhance the mechanical and flame retardant properties. In addition, the two-dimensional material is assembled in situ process does not use any organic solvent and a special process, having a green, fast, simple and so on, and is suitable for the preparation of open-celled silicone rubber or closed cell foam material in.
Preparation of the silicone rubber foam has excellent high temperature mechanical reliability, thermal stability and excellent flame retardancy . Adding a small amount (0.1-0.5 wt%) of graphene oxide can be significantly improved high temperature mechanical properties and thermal cycling stability of the silicone rubber foam, as compared to the conventional carbon-based foam (such as polyurethane and melamine foams), developed 0.1wt % graphene oxide reaction assembled nanocomposite material of silicone rubber foam having excellent flame retardancy, a vertical burning achieve UL94-V0 level. Meanwhile, the rate of heat release material, smoke release were significantly reduced. Limiting oxygen index tests show, 0.5wt% graphene oxide reaction assembled silicone rubber foam reached 31.5%, far superior to the silicone rubber foam was prepared physically blending and conventional surface coating.
found that the content of the low reaction assembled graphene oxide silicone rubber foam combustion in a stable structure, external carbon dioxide particles form a dense surface, an intermediate gray transition, the original structure remains inside the foam material. Further studies showed that, under conditions of high heat or flame, the thermal decomposition of the silicone molecules will promote the formation of nano silica thermal reduction of graphene oxide will both cooperate to form a dense graphene / nanosilica outer protective layer can be effectively suppressed temperature and oxygen attack on the inside of the organic molecules, so as to realize a silicon – carbon synergistic flame-retarding effect. Recent comparative study found (Chemical Engineering Journal, 2020, 393, 124724; IF: 8.355), and the layer structure of graphite oxide content alkylene sheet material has a significant impact on the flame-retarding effect and mechanical reinforcement. The study of high performance silicone rubber foam nanocomposite material design and development of a new way of thinking and method. Organosilicon Chemistry and Materials Technology Laboratory Graduate Li Yang , Cao Chengfei , joint PhD Li Schneider tied for the first author of the article, Tom Long Cheng researcher for the corresponding author. Research the National Natural Science Foundation of China, Zhejiang Provincial Natural Science Foundation of joint funding, Hangzhou Science and Technology Program silicon and fluorine fine chemicals such as collaborative innovation projects.