摘要
通过半连续乳液接枝聚合反应合成了聚丁二烯接枝苯乙烯和甲基丙烯酸环氧丙酯胶乳(PBg-PSG胶乳),然后向PB-g-PSG胶乳中加入了占其固体质量为3%,5%和7%的吐温-20.将掺吐温-20的PB-g-PSG胶乳拌入水泥砂浆,制得PB-g-PSG胶乳改性水泥砂浆.考察吐温-20掺量和聚灰比(质量比)对改性水泥砂浆流动度、抗压强度、抗折强度、保水率以及吸水速率的影响,并利用SEM观察改性水泥砂浆的微观形貌,分析吐温-20对PB-g-PSG胶乳的稳定作用.结果表明:随吐温-20掺量或聚灰比的增加,改性水泥砂浆流动度增加;改性水泥砂浆吸水速率随吐温-20掺量增加呈先降后增趋势;掺3%,5%和7%吐温-20的PB-g-PSG胶乳均能提高水泥砂浆的保水率(最高可达99.22%,质量分数);改性水泥砂浆的抗压强度均随聚灰比的增加而降低,且小于参比砂浆;改性水泥砂浆的抗折强度基本高于参比砂浆,且当聚灰比为10%时,最高可达9.45MPa;PB-gPSG胶乳对水泥水化物起黏合及桥接作用,并与之形成互穿网络结构,从而改善了水泥砂浆性能;吐温-20可使胶乳粒子表面形成一层很厚的水化层,阻碍胶乳粒子相互接近发生凝聚,令PB-gPSG胶乳稳定存在.
The PB-g-PSG latex was synthesized by semicontinueous emulsion grafting polymerization. Twain-20 was added to latex with 3 %, 5 % and 7 % of solid mass of latex. PB-g-PSG latex with Twain-20 was added to cement mortars to prepare PB-g-PSG modified cement mortar. The effects of use level of Twain-20 and polymer-cement ratio（by mass） on the fluidity, compressive and flexural strength, water retention rate and absorbing water speed of PB-g-PSG latex modified cement mortar were studied. Micro- structure of modified cement mortar was observed by SEM. The stability of Twain-20 to PB-g-PSG latex was analyzed. The results show that the fluidity of modified cement mortar is increased with increasing use level of Twain-20 or polymer-cement ratio. Absorbing water speed is decreased at first, and then is in- creased with increasing use level of Twain-20. PB-g-PSG latexes with 3 %, 5 % and 7 % Twain-20 increase water retention rate of cement mortar, and the maximum is 99.22^（by mass）. The compressive strength of modified cement mortars is decreased with increasing polymer-cement ratio, and is lower than that of control mortar. The flexural strength of modified cement mortars is basically higher than that of control mortar. The maximum of flexural strength of modified cement mortar is 9.45 MPa at 10% of polymer-cement ratio. Latex plays the bonding and bridging role to cement hydrates, and forms interpenetrating network structure, so as to improve the performance of cement mortar. Due to Twain-20, a thick hydration layer will be formed by the latex particle surface, hindering the latex particle close to each other and coagulation, with the result that the PB-g-PSG latex is more stable.
出处
《建筑材料学报》
EI
CAS
CSCD
北大核心
2014年第4期566-571,共6页
Journal of Building Materials
作者简介
赵文杰（1970-），男，吉林德惠人，长春工业大学副教授，博士．E-mail：zhaowenjie@mail．ccut．edu．cn
