Study On Polycarboxyl Water-Reducing Agent Prepared With Allyl Polyethenoxy Ether And Acrylic Acid As Main Raw Materials

Water-solution copolymerization has been carried out using acrylic acid(AA)and allyl polyethenoxy ether with different molecular weight(APOE-1200,APOE-2000,APOE-3000)as main raw materials,and using redox system as initiator.The effects of initiator concentration([I]),total monomer concentration([M]),polymerization temperature(T)on copolymerization rate(r)have been investigated,the relationships between r and[I],[M]or T are obtained and presented as follow:① For AA/APOE-1200 copolymerization,r∝[I]0.505[M]1.823e-5349/T,[η]∝[I]-0.881[M]1.028e8335/T;② For AA/APOE-2000 copolymerization,r∝[I]0.446[M]1.859e-4155/T,[η]∝[I]-1.094[M]1.195e7432/T;③For AA/APOE-3000 copolymerization,r∝[I]0.407[M]1.695e-3582/T,[η]∝[I]-1.283[M]1.024 e7329/T.The chemical compositions of copolymers prepared at low conversion(<10%)have been determined by acid-base titration method.The reactivity ratios of AA and APOE-1200(APOE-2000 or APOE-3000)have been calculated by YBR method,and are listed as follows.① For AA/APOE-1200 copolymerization,r1=1.185,r2=0.0347.② For AA/APOE-2000 copolymerization,r1=1.390,r2=0.0418.③ For AA/APOE-3000 copolymerization,r1=1.607,r2=0.0353.The high-range water-reducing agent has been prepared by adding appropriate molecular weight modifier and by controlling material-adding method,polymerization temperature and time,et al.The effects of the as-prepared water-reducing agent on water-reducing ratio and mechanical performance of cement paste,motar and concrete have been investigated.The performances of the as-prepared copolymers have been compered with those of the two commercial polycarboxyl wate-reducing agents.It is found that the water-reducing performances of copolymer-2000 are better than those of copymer-1200 and copolymer-3000.Additionally,compared with the two commercial polycarboxyl wate-reducing agents,copolymer-2000 possesses comparable total performances and better adaptability for different cements.