聚羧酸减水剂共聚单体活性及共聚物结构组成  

Monomer Reactivity and Copolymer Microstructural Compositions of Polycarboxylate Ether Superplasticizers

作　　者：王子明[1] 张琳 刘晓[1] 毛倩瑾[1] Ziming Wang;Lin Zhang;Xiao Liu;Qianjin Mao(College of Material Science and Engineering,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学材料科学与工程学院,北京100124

出　　处：《高分子材料科学与工程》2020年第10期29-35,共7页Polymer Materials Science & Engineering

基　　金：国家重点研发计划(2017YFB0310002)。

摘　　要：以过硫酸铵分别引发甲基烯丙基聚乙二醇醚(MAPEG)、异戊烯基聚乙二醇醚(IPEG)、乙氧基乙烯基聚乙二醇醚(VEPEG)大单体与丙烯酸(AA)小单体进行自由基共聚合反应,制备了一系列不同单体配比的3种低转化率(<15%)共聚物,并进行了凝胶渗透色谱、高效液相色谱测试,通过K-T法计算得到了3个共聚体系中单体竞聚率分别为r(MAPEG)=0.017,r(AA)=1.700;r(IPEG)=0.042,r(AA)=1.630;r(VEPEG)=0.250,r(AA)=7.060。竞聚率结果表明,丙烯酸比大单体有更高的共聚活性;对比3种大单体共聚合活性,VEPEG大单体有更高的竞聚率且在链增长阶段显示出更高的活性;VEPEG-AA共聚体系的共聚物组成曲线符合一般理想共聚特征,而MAPEG-AA、IPEG-AA共聚物组成曲线表现出非理想共聚特征。Polycarboxylate ether(PCE)based superplasticizers were synthesized from three polyether macromonomers,methyl allyl polyethylene glycol(MAPEG),isoprenyl poly ethylene glycol(IPEG)and vinyloxyethyl ether polyethylene glycol(VEPEG)with acrylic acid(AA)via aqueous free radical copolymerization initiated by ammonium persulfate(APS).The copolymer compositions from different monomer feeding mole ratios were calculated based on the residual amounts of macromonomers and acrylic acid obtained from the calibration of gel permeation chromatography(GPC)and high performance liquid chromatography(HPLC).The monomer reactivity ratios were obtained through K-T method for the three copolymerization systems under low conversion rate conditions(<15%),which are expressed as r(MAPEG)=0.017,r(AA)=1.700;r(IPEG)=0.042,r(AA)=1.630;r(VEPEG)=0.250,r(AA)=7.060.The reactivity results of monomers indicate that acrylic acid is more active than three macromonomers in each copolymerization system.Comparing the copolymerization activities of three macromonomers,the copolymer composition curve of VEPEG-AA can be generally regarded as ideal copolymerization while MAPEG-AA and IPEG-AA copolymer are non-ideal copolymerization.Among the three macromonoers,VEPEG shows the higher instantaneous conversion rate in chain growth step but a lower molar fraction in copolymer due to steric hindrance,VEPEG-AA copolymer with higher molecular weight features a longer backbone and more sparse side chains.

关 键 词：聚羧酸减水剂 竞聚率 单体活性 共聚物组成 

分 类 号：TU528.042.2[建筑科学—建筑技术科学]