The Synthesis And Properties Of Brominated Epoxy Resin

As a novel brominated flame retardant,brominated epoxy resin possesses excellent flame retardancy,migration resistance,low toxicity and high thermal stability and it has little influence on mechanical properties of the materials.More importantly,it has made itself a representative of novel environment-friendly flame retardants because there is no problem involving dioxins.However,the research and production of brominated epoxy resin in our country is still on a preliminary stage especially high molecular weight brominated epoxy resin which is almost vacant.So,it has a profound strategic significance to synthesize brominated epoxy resin in order to break monopoly of foreign products and achieve autarky.Firstly,to overcome the disadvantages of adding excess epichlorohydrin in conventional synthesis process,the molar ratio of tetrabromobisphenol A to epichlorohydrin was fixed at 1:2. Effects of reaction conditions on the reactions were studied and the optimum reaction conditions were determined.Tetrabromobisphenol A based diglycidyl ether with epoxide equivalent at 400 g/ml was successfully synthesized as the raw material of high molecular weight bromated epoxy resin,then its structure was characterized and thermal properties were tested.Then,high molecular weight bromated epoxy resin was generated by tetrabromobisphenol A based diglycidyl ether,tetrabromobisphenol A and self-made catalyst.The structure was characterized and thermal properties were tested.The optimum reaction conditions were determined:the quantity of catalyst was equal to 0.6%of feedstocks,cyclohexanone was chosen as solvent,reaction system concentration was 75%at the beginning and was diluted to 60%after a period,the reaction temperature was 150～160℃,the reaction time was 8.5 h,and the Mw of the polymer reached 6.04×10~4.Finally,polymer molecular weight was controlled by changing the feed ratio of tetrabromobisphenol A based diglycidyl ether and etrabromobisphenol.Thermal properties and bromine contents with different polymer molecular weight were tested.The results showed that with the increase of molecular weight,95%weight loss temperatures increased significantly and bromine content also increased.Moreover,epoxy terminated was terminated by tribromophenol,and thermal properties(pre and post termination) were investigated.The results showed that termination had little influence on thermal properties.