EFFECT OF MOLECULAR STRUCTURE OF POLYCARBOXYLATE SUPERPLASTICIZERS ON GYPSUM DISPERSION
EFFECT OF MOLECULAR STRUCTURE OF POLYCARBOXYLATE SUPERPLASTICIZERS ON GYPSUM DISPERSION
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DOI：
10.3724/sp.j.1105.2011.09405
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发表时间：
2011-03
影响因子：
1.9
通讯作者：
Fu Lefeng;Deng Zui-liang;Z. Yi;Zheng Bai-cun;Yu Jianguo
中科院分区：
文献类型：
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作者：
Fu Lefeng;Deng Zui-liang;Z. Yi;Zheng Bai-cun;Yu Jianguo
研究了甲基丙烯酸-甲氧基聚乙二醇单甲基丙烯酸酯(MAA-MPEGMA)共聚物、甲基丙烯酸-聚乙二醇单烯丙基醚(MAA-APEG)共聚物、丙烯酸-聚乙二醇单烯丙基醚(AA-APEG)共聚物和聚丙烯酸(PAA)均聚物等梳型聚羧酸接枝共聚物对石膏颗粒分散性和石膏浆料凝固时间的影响。侧链长度、低分子量或高电荷密度均能改善分散效果并延长固化时间。在所有研究的聚合物中，电荷密度最高的PAA均聚物具有最好的分散效果和最长的固化时间。侧链和主链长度都很短的共聚物具有更好的分散能力和更长的固化时间。含有丙烯酸锚定基团的共聚物比含有甲基丙烯酸锚定基团的共聚物具有更好的分散能力和更长的固化时间。化学结构的影响并从表面和界面化学的角度对石膏的分散性及分散-吸附机理进行了阐述和讨论。结果表明，聚羧酸减水剂对石膏粉的分散机理是通过影响石膏与水的凝结时间和水化反应来实现的，与其说是位阻效应，不如说是静电斥力效应。
Effects of comb-type polycarboxylate grafted copolymers such as methacrylic acid-methoxy polyethylene glycol monomethacrylate(MAA-MPEGMA) copolymers,methacrylic acid-polyethylene glycol monoallyl ether(MAA-APEG) copolymers and acrylic acid-polyethylene glycol monoallyl ether(AA-APEG) copolymers and polyacrylic acid(PAA) homopolymer on dispersion of gypsum particles and set time of gypsum slurries were studied.Polymers with short side-chain length,low molecular weight or high density of charge have improved dispersing effects and longer set time.In all polymers studied,PAA homopolymer with highest density of charge has the best dispersing effects and longest set time.Copolymers containing very short length of both side chain and backbone have better dispersion ability and longer set time.And copolymers containing anchoring groups of acrylic acid have better dispersing ability and longer set time than that of copolymers containing anchoring groups of methacrylic acid.Effects of chemical structure on dispersion of gypsum and dispersion-adsorption mechanisms were also explained and discussed from the point of surface and interface chemistry.It shows that the dispersing mechanism of polycarboxylate superplasticizer to gypsum powder is realized through affecting set time and hydration reaction of gypsum with water,and is more like the electrostatic repulsion effect than the steric hindrance.