摘要
为了研究聚羧酸减水剂(PCE)在共聚合过程中分子结构的形成过程、各时间段内生成聚合物的酸醚比偏离设计酸醚比的规律与范围,以及不同引发体系对聚羧酸减水剂分子结构形成过程的影响,以异丁烯基聚乙二醇醚(MAPEG)与丙烯酸(AA)作为共聚单体,采用过硫酸铵(APS)和过氧化氢-抗坏血酸(H2O2-Vc)两种引发体系,按照双滴加工艺合成了聚羧酸减水剂。采用凝胶渗透色谱(GPC)和高效液相色谱(HPLC)测定反应体系中不同时间段内各单体和聚合物的含量,得到不同反应阶段生成聚合物的分子量及分散度、均方回转半径和单体组成(酸醚比)等参数,分析总结了APS和H2O2-Vc引发体系下PCE共聚合反应过程中聚合物形成过程的特点。研究发现,在过硫酸铵引发体系下,90 min时形成主链较长的聚合物,在过氧化氢-抗坏血酸引发体系下,60 min时形成主链较短的聚合物。并且在两种引发体系下,各时间段内生成聚合物的酸醚比都偏离初始设计值,反应初期(0~120 min)生成聚合物的酸醚比小于设计值,反应中期(120~240 min)生成聚合物的酸醚比高于设计值,在单体滴加结束时达到最大值,最大偏离值超过设计酸醚比的160%以上,反应后期(240~330 min)生成聚合物的酸醚比取决于引发体系和工艺控制。
In order to study the formation process of molecular structure of Polycarboxylate Superplasticizer(PCE)during copolymerization,the rule and range of deviation of acid/ether ratio from designed acid/ether ratio in each time period,and the influence of different initiator systems on the formation process of molecular structure of PCE,PCE was synthesized by using methyl allyl polyethylene glycol(MAPEG)and acrylic acid(AA)as co-polymerization monomers,initiated by ammonium persulfate(APS)and redox initiation system(H2O2-Vc)according to double-titration addition process.The content of monomers and formed polymers in the reaction system were determined by gel permeation chromatography(GPC)and high performance liquid chromatography(HPLC).The molecular weight and dispersity,mean square radius of rotation,compositions of monomers(acid/ether ratio)and monomer conversion were obtained at different reaction stages.The characteristics of polymer formation during PCE copolymerization in APS and H2O2-Vc systems were analyzed and summarized.It was found that in APS system,a polymer with a longer main chain was formed at 90 minutes,and in H2O2-Vc system,a polymer with a shorter main chain was formed at 60 minutes.The acid/ether ratio of the polymer formed in the two initiator systems deviated from the initial design value in various copolymerization period.The acid/ether ratio of the polymer formed in the initial reaction(0-120 minutes)was less than the design value,and the acid/ether ratio of the polymer formed in the middle reaction(120-240 minutes)was higher than the design value.At the end of monomer dropping,the maximum deviation value was more than 160%of the designed acid/ether ratio.The acid/ether ratio of the polymer formed at the late stage(240-360 minutes)depends on the initiation system and process control.
作者
王子明
赵美丽
张杨
WANG Ziming;ZHAO Meili;ZHANG Yang(College of Material Science and Engineering,Beijing University of Technology,Beijing 100124,China;Institute of Technical Information for Building Materials Industry,Beijing 100024,China)
出处
《化学反应工程与工艺》
CAS
北大核心
2019年第3期234-241,共8页
Chemical Reaction Engineering and Technology
基金
国家自然科学基金(51621003)。
关键词
聚羧酸减水剂
结构形成
分子量
均方回转半径
酸醚比
polycarboxylate superplasticizer
structure formation
molecular weight
mean square radius of gyration
molar ratio of acid to ether
