| Water-soluable carboxylate polymer is widely used in daily life, especiallyin the fields such as concrete admixture polycarboxylate superplasticizer (PC)and leather retanning agent. Concerning the significant role in economic, thispaper discussed the synthesis method of PC, absorption characters of anchorgroups (carboxyl and sulfonate groups) in PC and the effect of side chain on theperformance of PC, and what’s more the long-side chain water-soluablecarboxylate polymer was studied as a retanning agent.In the discussion of synthesis methods of PC, four different ways wereinvolved. The results showed that high performance maleic anhydride (MAH)type PC (PC-M) can be abtained when the initiator of ammoniumperoxydisulfate (APS) dropped into the solution containning MAA，hydroxylterminated poly(ethylene glycol) methacryloyl vinyl ether (HPMA) and sodiummethylallyl sulfonate (SAMA). The best way to synthesize acroleic acid (AA)type PC (PC-A) was that dropping of APS and AA repectively into the solutionof HPMA. Based on the two different methods and single facor analysis method,the primery performance PC-M can be got at the molar ratio of n (MAH)∶n(HPMA)∶n(SAMA)=2.75∶1∶0.3when molar fraction of APS was4.5%related to all of the vinly monomers, and the priminent performance of PC-A canbe got at the molar ratio of n(AA)∶n(HPMA)∶n(SAMA)=3∶1∶0，when themolar fraction of APS was3.8%all of the vinly monomers. The fluidity ofcement pastes were277mm for PC-M and283mm for PC-A when the dosagewas0.2%at the water-cement ratio (w/c) of0.29.The absorption characteristic of carboxyl and sulfonic groups was studiedbased on the calcium carbonate as model of cement via ultraviolet-visiblespectrophotometer. The results indicated that the influence was differentaccording to the types of ions in the bulk of solution because of the intrinsicproperties of carboxyl and sulfonic groups. The absorption amount of sulfonic groups was larger than carboxyl groups, the increase of pH could result in theincrease of absorption of carboxyl but seldom increase in absorption wasobserved for sulfonic group.Effects of the PC molecule linkage mode on the performance of concretepaste were investigated using slump loss test and thermogravimetric analysis(TGA) and tests of fluidity, absorption, and setting time. Results showed that thelinkage mode between main chains and PEO branch chains in PC molecules hadan important influence on performance of cement paste and concrete preparedfrom them. PC with ester linkages can endow the cement paste with higherfluidity and higher water-reduction ratio resulting from the higher absorptionamount on the cement particles. And this is related with the alternatingdistribution of the carboxyl groups and branch chains of PEO when differentmacromonomer was involved in the preparation of PC. PC containing esterlinkages were more vulnerable than PC with ether linkages in an alkalienvironment, leading to quicker slump loss and shorter setting times. In contrast,PC with ether linkages had excellent fluidity and slump-flow stability. A slightlydifferent ettringite hydration product was observed during the early period of thehydration of cement paste that employed these two PC.A series of retanning agent were synthesized from HPMA with methacrylicacid (MA) and MAH respectively. The effects of monomer dosage on theretaning properties were discussed and the compare studies indicated that MAwas more suitable than MAH to synthsize long-side chain retaning agent, thattermed as RA-Y and prefprmance well in increase in thickness and colorproperty. The retanning agent with primmory properties could get at the molarratio of n(MA)∶ n(HPMA)=26.7∶1. Application of retanning processendowed the retanned leather an excellent increment in thickness and inproperties of plump, softness, good elasticity and strong foaming feels.The merit of this study was that the influences of monomer on the synthesisand molecular structure of PC and RA-Y and consequence in the properties ofproduction were studied from the active of monomers. |
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