ACS Resin Synthesized By High Temperature Solution Polymerization

ACS resin is a kind of grafting copolymer,which is prepared by grafting acrylonitrile(AN)and styrene(St)to the main chain molecules of chlorinated polyethylene(CPE).Due to use the saturate CPE rubber substituting for the butadiene in ABS resin,ACS resin has not only many excellent properties of ABS resin but also flame retardant,weather resistance properties,antistatic properties,and can meet the need of some industries,such as the high flame retardant,weather resistance,antistatic and thermal aging properties,for special ABS resin.ACS resin is synthesized by the water phase suspension polymerization method in industry.Its advantage is lower reaction temperature and easy to control,and the disadvantage is that the monomer and chlorinated polyethylene in the water phase is more difficult to dissolve and swelling,the reaction time is too long,the product quality is not stable,and the waste water processing problems.High temperature continuous solution polymerization has become a new generation synthesis process of ACS resin in that it is of the advantages of continuous,simple process,short process,low energy consumption,low cost,less"three wastes",energy-saving,and environmental protection and so on.So far the new process has not yet developed in our country.Therefore,it is necessary to study the high temperature continuous solution polymerization of ACS resin.The high temperature continuous solution polymerization of ACS resin was studies with toluene as solvent,di-tert-butyl peroxide as initiator,t-dodecyl mercaptan as chain transfer agent.The effects of the polymerization temperature,reaction time,monomer ratio,chlorination degree and swelling condition of CPE rubber on the grafting ratio,molecular weight and phase morphology of SAN resin matrix phase were investigated,and then the relationship between the grafting rate,phase morphology,mechanical properties and process ability was investigated.The factors affecting the structure and properties of ACS resin were clarified.The process and ingredient of polymerization for synthesizing high performance ACS resin were investigated,and the following conclusions were drawn:(1)In the high-temperature solution-polymerized process of ACS resin,the grafting reaction of CPE-g-SAN graft copolymer occurs mainly in the low conversion stage of the polymerization reaction,and its reaction does not occur during the later period of the polymerization process.(2)The results show that the grafting rate,the molecular weight and phase morphology of the SAN resin are influenced by initiator content,chain transfer agent content,St/AN weight ratio,solvent ratio,CPE rubber content,swelling conditions,and chlorination degree.Of these,the amount and ratio of initiator and chain transfer agent are the main factors.(3)For synthesizing ACS resin by high-temperature solution polymerization,the grafting rate,the molecular weight of SAN resin for the matrix phase and the amount of CPE rubber should be controlled at 22-28%,1×10~5~1.2×10~5 and 22~25 wt%,respectively.(4)The optimal polymerization conditions for synthesizing ACS resin with high-temperature solution polymerization are the follows:the polymerization temperature of 130~oC,the reaction time of 4~6h,the optimal feeding amount were toluene of 35wt%,CPE of 25wt%,styrene/acrylonitrile weight ratio of 3:1,initiator of 0.05~0.1wt%,chain transfer agent 0.1wt%;Under the above conditions,the ACS resin is of the impact strength of 42~57kJ/m~2,tensile yield strength of 25~32MPa,elongation at break of 90~100%and elastic modulus of 1300~1400MPa.