Study On The Polymerization Process Of ABS Resin Via Continuous Bulk Reactors

Acrylonitrile-butadiene-styrene terpolymer?ABS?is a kind of thermoplastic resin with excellent comprehensive performance,widely used in automobile,household appliances,electronics,building materials and other fields.Along with the national policies and regulations of environmental protection,the newly-developed method of continuous bulk technology of ABS production,which is of simpler technological process,environmental friendly and also high product purity,will gradually replace the primitive method of emulsion grafting blending method,which is environmentally polluting and of high content of residual,becoming the future development direction in the field of domestic ABS resin.At present,the main problem of continuous bulk technology is the lower impact strength of the product and the less product species.To solve this problem,the thesis was cooperated with the North Huajin Chemical Industries Group Corporation,on the basis of results of small-scale experiment,using the self-design,pilot-scale equipment,to investigate the relationship between rubber and polymerization process and the structure and properties of product.By optimizing the sol formula and polymerization process,the impact strength of products was improved,and the industrial application experiment was also carried out on the process device.The microstructure of three kinds of rubber used in this thesis were studied,according to the existing sol formula,seven groups of sol formula with different viscosity were designed for pilot tests.The relationship between sol formula with single or compound rubber and the grafting rate,molecular weight,microstructure of the rubber particle size of the final products were detailed discussed.Also,the rubber toughening effect was evaluated through the instrumented impact test.From the result,we could tell the optimized toughening effect was realized when the ratio of 255 rubber and 97B rubber is 2:1.The impact strength of ABS was raised from 152.8 J/m to 175.2 J/m when the sol viscosity was reduced from 172.1 m Pa·s to136.3 mPa·s.Based on the formula determined above,the experiments were carried out through the pilot-scale equipment.The reaction temperature,amount of initiator and chain transfer agent,stirring speed,the amount of mineral oil and other process parameters were investigated respectively,to make clear relationship with the phase transition process,the microstructure and properties of product,in order to get the optimal impact strength of the product.Results showed that,the optimal result appears,when the temperature of the 1^st,2^nd and 3^rd reactor reduced 3?,the temperature of the 4^th reactor raised 4?,the addition of chain transfer agent reduced to 50%normal value in the 1^st reactor,the addition of chain transfer agent in the 2^nd reactor decreased to 75%normal value,and the addition of chain transfer agent in the3^rd reactor decreased to 67%normal value,the stirring rate of the 2^nd reactor increased to133.3%normal value,1%mineral oil was in addition added into the sol formula.Under these conditions,the impact strength of the product was increased to 245.8 J/m.The application of industrial ABS production unit in North Huajin Chemical Industries Group Corporation was carried out based on the results of the pilot experiment.The impact strength of the generic brand product was increased to 170J/m under the optimization of toughening rubber and polymerization process.The impact strength of the product with medium impact resistance was increased to 220J/m.The above products have been produced in batches and showed stable performance,which can meet the requirements of continuous production on industrial equipment.In this trial the pilot results was successfully industrialized.