Butadience And Polar Monomer Emulsion Copolymerization And Safety Control

Nitrile-butadiene rubber(NBR)is currently the most used special synthetic rubber,the polar groups and unsaturated double bonds in the NBR structure make the processed vulcanized rubber excellent in oil resistance and physical and mechanical properties,and it is widely used in important industries such as product development and coal mining.At present,the widely used NBR in the market is generally combined with acrylonitrile content of 24%?35%.In this combination,NBR with AN content generally has problems of low oil resistance,cold resistance and low elongation at break,so it will be to a certain extent limit the scope of application of NBR.In this paper,based on the emulsion polymerization method,the properties of two polar monomers,butyl acrylate(BA)and methyl methacrylate(MMA),are used to improve the performance of NBR.In the polymerization process of butadiene and acrylonitrile,polar monomers were added respectively to synthesize butadiene-acrylonitrile-acrylate terpolymer,and the polymerization reaction,the structure and properties of the polymerization products in the experimental process were studied to provide a basis for further performance optimization of the modified NBR.The following are the research contents and main conclusions of this paper:On the basis of fixed Bd:AN=67:33,5,10 and 15 parts of BA were added for ternary polymerization respectively.The results showed that the addition of 5 parts of BA could improve the polymerization conversion rate,while 15 parts of BA could prolong the induction period of polymerization,but the conversion rate could reach70%?80%after 6h of reaction.When BA was used as monomer change initiating system,MMA was added and the ratio of the formula was changed when AN was fixed to 23.The results showed that MMA slightly increased the polymerization conversion rate compared with BA.In the polymerization process,the addition of BA and MMA can reduce the average particle size of the emulsion.Meanwhile,the emulsion test results show that the monomer formula and initiator system used in the emulsion polymerization system make the emulsion have good stability.Characterization and testing of the microstructure of synthetic rubber by ~1H NMR,IR,Microgel content,Mooney viscosity and glass transition temperature,and then raw rubber BA5,BA10,BNBR₁,BNBR₃,and Russian CKH3365,CKH2665 were selected for vulcanization processing to compare and analyze the influence Synthetic rubber Vulcanization properties Vulcanized rubber Cold resistance Factors of physical and mechanical properties and oil resistance.The FT-IR and ~1H NMR diagrams show that the polymerization products added with the monomer acrylate all contain acrylate groups.During the ternary emulsion polymerization process,BA and MMA are easier to combine with AN than Bd.When the fixed monomer Bd:AN=67:33,the content of bound AN in the final product of the polymerization of 10 parts of BA and 15 parts of BA is closer to 33.When Bd:AN=67:33,the Microgel content of BA5 and BA10 is less than 2%,and the single when 23 parts of AN is fixed,the Microgel content of BNBR₂is less than 1%,and the Mooney viscosity value of synthetic rubber will increase with the increase of Microgel content.When 33 parts of AN monomer,with the increase of BA structure content,the glass transition temperature first decreased and then increased,and the glass transition temperature of BA10 was-26.5?;appropriate BA structure content has a strong ability to reduce the glass transition temperature,when the BA structure content is too much,the glass transition temperature reduction level decreases.When the monomer AN is 23 parts,the addition of the BA structure is more conducive to reducing the glass transition temperature of the nitrile rubber than the addition of the MMA structure.Vulcanization processing and testing of vulcanized rubber properties show that the existence of BA structure and MMA structure reduces the scorch time t₁₀of vulcanized rubber compared with CKH rubber,shortens the rubber vulcanization induction period;and relatively reduces the wear resistance of synthetic rubber,but increases Deformation resistance of synthetic rubber.BA10 has the smallest M_Lvalue and has the best fluidity.When the fixed fraction of AN is 23,the BA structure can better improve the crosslinking density of the vulcanized rubber than the MMA structure;the DMA test of vulcanized rubber shows that the glass transition temperature of BA10 is-27?,and it has excellent cold resistance similar to CKH3365.The addition of BA structure and MMA structure will reduce the hardness and tensile stress of rubber,and appropriate amount of MMA and BA structure can enhance the tensile strength of rubber.At the same time,it will greatly improve the elongation at break of nitrile rubber.The mechanical properties test after oil resistance shows that both BA and MMA structures can improve the oil resistance of vulcanized rubber,the mechanical properties after oil resistance are in Shore A hardness and fracture Elongation is the best.Through the pre-risk analysis,the possible risks in the emulsion polymerization process and the experimental problems encountered in the polymerization experiment,it is known that the polymerization temperature and initiation system selected for the experiment are within the controllable range,and the corresponding safety protection measures were put forward for the storage and use of raw materials and the operation of the emulsion.