Study Of The Phase Transition Process And Performance Evaluation During The Preparation Of High Performances ABS Resin By Bulk Polymerization

The continuous bulk polymerization process is still in the exploratory stage in China,and most of the production devices and process formulas are still being imported.There is still a big gap in the research on the thermodynamics and kinetics of the polymerization process.In this paper,a series of ABS resins were synthesized by bulk polymerization with polybutadiene rubber,styrene-butadiene rubber,and their combinations as toughening agents,and the influence of different rubber microstructure content on the phase transition process and the difference of mechanical properties in the process of synthesizing ABS resins was explored;Tert-dodecyl mercaptan(TDDM),n-dodecyl mercaptan(CTA),and 2,4-diphenyl-4-methyl-1-pentene dimer(S-A)as three molecular weight modifiers in industrial production were investigated.The effects of different chain transfer agents on the phase transition process and the differences in mechanical properties in the preparation of ABS resin were compared.The experimental results show that the phase transition process of ABS resin prepared by different kinds of rubber has no obvious change.The impact strength of low cis-polybutadiene LND-97 B rubber as toughening agent is the best,reaching 284.27 J/m,the compatibility between the rubber phase and resin is the best,and the molecular weight of the substrate phase is the largest.CTA,TDDM,and S-A can be effectively substituted in the industrial production process.The impact strength of ABS resin prepared in the TDDM system and S-A system is higher than that in the CTA system,which is as high as 347 J/m and 351 J/m respectively.With the increase of the content of the chain transfer agent,the interfacial adhesion between the two phases is enhanced,so the impact strength of ABS resin is improved.The effects of different polymerization conditions and formulations on the phase transition process and mechanical properties of high-performance ABS resins were systematically studied from the aspects of shear rate,initiator type,polymerization temperature,and diluent type.The final particle morphology of ABS resin was observed under the transmission electron microscope(TEM),and the impact section morphology of a series of ABS resins was observed by scanning electron microscope(SEM).The effects of different polymerization processes and formula parameters on the phase transition process and mechanical properties of ABS resin were systematically studied.The experimental results show that proper stirring rate is beneficial to the formation of rubber particles,promotes the completion of phase transition,and increases the molecular weight of the SAN resin phase;Ethylbenzene,as a good solvent in the polymerization process,is beneficial to the grafting reaction of rubber,thus improving the compatibility between two phases;Polymerization temperature is the direct factor affecting the decomposition rate of initiator system.Different initiator systems have different half-lives,which have a great influence on the polymerization rate,the viscosity of the reaction system,and the molecular weight of continuous-phase SAN resin.