Research On Synthesis And Performance Of Polycarboxylic Acid Type Water Reducer

This article research work take the country "973" the plan project "High performance Cement Preparation And Application Basic research" the sub- topic chemistry sur- medicinal preparation to the high performance cement hydration advancement influence as a background,The main achievements are listed as follows.1.Research on relation between structure and function of water reducer:All structures of polycarboxylic acid type water reducers follow certain rule: some functional groups, such as carboxyl group and sulfonic group, are introduced into the main chain of comb-shape polymer, to provide charge repulsion; and in the branched chain, poly oxyalklerhers side chains of different lengths are introduced, oxide of ether combies with hydrone to form hydrogen bond, and to form solvation cubic protective layer, the layer has dispersibility and retentivity; by adjusting ratio of each functional group in main chain of polymer, lengths of main chain and side chain, and numer of graftion, to reach equlibrium of structure. Under the guideline of the above theory, in the research, polyethylene glycol single methyl ether, methylacrylic acide, maleic acid and such unsaturated vingl monomer are chosed as raw materials for polymerization, to synthesis new type polycarboxylic acid type water reducer.2. Reseach on esterification craft of synthesis of middle macromonomer:The optimal esterification conditions of synthesis of MAMG with MA and MG are: self-made ZJ as polymerization retarder, weight of catalyst is 8～9 percent of reactors, toluene as solvent, mole ratio of MA: MG is 1.5:1, temperature is 140℃, reaction time is 6 hours;The optimal esterification conditions of synthesis of MSMG with MS and MG are: weight of catalyst is 8～9 percent of reactors, toluene as solvent, temperature is 145℃, reaction time is 5 hours;3. Research on combined polymerization of water reducer polymer:If mole ratio of MAMG:MA is 1.5:1, weight of iniatior is 7 percent, temperature is 90～100℃, reaction time is 7-8 hours, performance of polymer is the best;If mole ratio of MSMG:MA is 1.1:1, weight of iniatior is 7 percent, temperature is 90～100℃, reaction time is 7～8 hours, performance of polymer is the best.Compare dispersibility of the water reducer synthesised by MA as esterification monomer with that of the water reducer synthesised by MS as esterification, the cement paste initial fluidity of former is more larger than the latter, the fluidity loss with time is similar.4. Research on performance of water reducer synthesised:Add polymerization of water reducer synthesised into cement paste, the optimal weight is 0.15～0.2 percent, cement paste fluidity and retentivity is approach to that of foreign type;Use the water-reducer synthesised to make up plain concrete and concrete added with fly ash fume, slump loss is small, without segregation, adhesive aggregation is good ; total performance is approach to foreign type;By analysising hydration heat and electricity performance of cement, use water reducer synthesised can reduce hydration heat, retard heat peak, and reduce concrete cracking caused by hydration temerature difference.5. Analysis of industrilization practicability:Procedure of synthesis craft of polycarboxylic acid type water-reducer is easy to control, without high requirment towards equipment, so it is practicable for industrialization.