Study On The Synthesis Of Polybromostyrene

Polybromostyrene (PBS) is a new type of polymer brominated flame retardants.When it was added to materials, the materials had the good thermal stability, low toxicity, good compatibility, and hard to move out. Therefore polybromostyrene flame retardants obtained important applications in the field. With the rapid development of the domestic market, the demand of bromine-based flame retardant polymer products in China becomes more and more. Therefore, to strengthen the development of polybromostyrene flame retardant polymer has an important theoretical significance and value..In this paper, we first reviewed the preparation processes of polybromostyrene and the optimal conditions of related intermediate products. The experimental contents mainly included three parts, such as the bromination reaction of β-bromoethylbenzene, the synthesis of bromostyrene monomer and the preparation of polybromostyrene successively. Based on each step of the synthesis processes, this paper studied the selection of additives, reaction parameters and post-treatment processes in each experiment step. Through a series of modification and verification experiments, We had achieved some experimental results and got the high-performance products.In this paper, the experiments used β-bromoethylbenzene (P-Br) as raw materials and synthetized β-bromoethylbromobenzene(β-BrBrn), bromostyrene monomer and polybromostyrene. First of all, under the catalysis of Lewis acid Fe, β-Br occurred bromide reaction in benzene ring to generate a series of different bromine content of β-BrBrn. Through research, the optimal reaction condition was determined:when the catalyst amount was 1.0%, the ratio feed of bromine and β-Br was 3.5, holding temperature was 30℃, and holding time was 2h, the reaction could achieve suitable bromine content, and the β-bromoethyl bromobenzene were characterized and analyzed by GC, IR and HNMR means. Then, we synthesized bromostyrene monomer with β-BrBrn and sodium alkoxide. Through research, the optimal reaction condition was determined:we used isopropyl alcohol as solvent, the most suitable sodium hydroxide concentration was 50%, and the suitable feeding ratio of P-BrBrn and sodium hydroxide was 1:5. The reaction temperature and the optimal reaction time were 40℃ and 4h, the bromostyrene monomer were characterized and analyzed by IR and HNMR means. Finally, we polymerized bromostyrene monomer by solution polymerization method. Then, we discussed the effects of solvent, comonomer, molecular weight modifier and initiator. Moreover, we analyzed the products by TGA and GPC test means. Through research we got a 1% weight loss temperature of more 300℃ and white polybromostyrene under high-boiling solvent o-dichlorobenzene; We obtained the best color with comonomer glycidyl methacrylate; We gained the polybromostyrene with molecular weight of 10,000 to hundreds of thousands by adjusting the n-dodecanethiol the amount, and achieved a narrow molecular weight distribution and controllable molecular weight in some range. Besides, this paper observed the molecular weight and yield change regulation by changing the amount of molecular weight modifier n-dodecanethiol and initiator azobisisobutyronitrile. The yield could reach more than 90%. In addition, we made 2 to 4 times amplification reactions on raw materials and gained a higher molecular weight polybromostyrene by changing the ratio of the feed additives. Based on the knowledge of the processes about brominated polystyrene during the internship, we simply designed the synthesis processes flow diagram of polybromostyrene and done the groundwork for the synthesis and industrialization in the future.