Research On Comonomer Activity Of Polycarboxylate

So far, Polycarboxylate often rely on a large number of exploratory trials to optimize the performance of water-reducing agent, but its structure copolymer molecular conformation is lack of clear information. In order to better design Polycarboxylate molecular structure, properties and guide the preparation and application of Polycarboxylate, it is need to study the activity of different macromonomer with a particular monomer(indicates with reactivity ratio), to guide the preparation and application of Polycarboxylate. For the current problem of lacking of Polycarboxylate comonomer reactivity ratio data, we carried out basic research of Polycarboxylate comonomer active issues.Firstly, we have researched isobutylene alcohol ethoxylates(HPEG) with acrylic(AA) and maleic anhydride(MA) respectively; isoamyl alcohol ethoxylates(TPEG) with acrylic acid(AA) and maleic anhydride(MA) respectively, totally four copolymerization system. Utilizing reactivity ratio data, monomers manner, copolymerization behavior and polymerization mechanism have studied. The results show: under the condition of 50?, ammonium persulfate(APS, 1%) as initiator, HPEG-AA system reactivity ratio was r1(HPEG) = 0.016, r2(AA) = 1.70; TPEG-AA System reactivity ratio was r1(TPEG) = 0.052, r2(AA) = 1.61. Two monomers are basically not occur all together, but the copolymer tends HPEG with AA and AA stronger than TPEG, that HPEG-AA system, AA homopolymerization to form an active backbone segment is higher than the TPEG-AA system. HPEG-MA system reactivity ratio was r1(HPEG) = 0, r2(MA) = 0.39, and presenceconstant ratio points F1 = f1 = 0.38, ratio of acid ester is 1.64. TPEG-MA system reactivity ratio was r1(TPEG) = 0.18, r2(MA) = 0.92, constant ratio points was F1 = f1 = 0.38. When the ratio of acid ester is 10.5, the copolymer composition is equal to the monomer composition.Secondly, Q-e values of HPEG and TPEG were calculated by Alfrey-Price equation, obtained basic data of comonomers activity. According to Alfrey-Price equation and the reactivity ratio of HPEG-AA,Q1 and e1 of HPEG is 0.146,-1.649 respectively. Similarly, Q1 and e1 of TPEG is 0.168,-1.32. The results showed that TPEG was easier than HPEG into free radicals, involved in the radical copolymerization reaction.Finally, micro-structure and chains distribution of P(HPEG-co-AA) were analyzed when the feed ratio of HPEG and AA was 1:4 and 1:2,which shows one way of analyzing microstructure based on reactivity ratios data.