PB-g-PSG胶乳改性水泥砂浆的性能

Properties of PB-g-PSG Latex Modified Cement Mortars

通过半连续乳液接枝聚合反应合成了m(聚丁二烯)/m(苯乙烯)/m(甲基丙烯酸环氧丙酯)为50/50/0,50/49/1,50/46/4的3种聚丁二烯接枝聚苯乙烯(St)和甲基丙烯酸环氧丙酯(GMA)共聚胶乳(PB-g-PSG胶乳).水灰比为0.4(质量比),将3种PB-g-PSG胶乳用于制备胶乳改性水泥砂浆,考察了GMA含量和聚灰比对该砂浆的流动度、抗压和抗折强度以及吸水速率的影响,并与SD623羧基丁苯胶乳改性水泥砂浆进行了性能对比试验.结果表明:在一定掺量范围内,3种PB-g-PSG胶乳改性水泥砂浆的流动度随GMA含量的变化并不明显,但均随聚灰比的增加而增加;PB-g-PSG胶乳能显著降低水泥砂浆的吸水速率;PB-g-PSG胶乳的掺入对水泥砂浆的力学性能有重要影响,这种砂浆的抗压强度随聚灰比的增加而降低,且小于参比水泥砂浆,聚灰比小于10%(质量分数)时,抗折强度大于参比水泥砂浆,最高可达9.65MPa;PB-g-PSG胶乳可作为水泥改性剂使用.

The PB-g-PSG latex was synthesized by semicontinueous emulsion grafting polymerization,and the mass ratios of polybutadiene to styrene ranged from 50/50/0,50/49/1 to 50/46/4.PB-g-PSG latex was used to modify cement mortar in the constant water-cement ratio of 0.4.The effects of GMA content and the polymer-cement ratios on the flow,compressive and flexural strength and water absorption rate of PB-g-PSG latex modified cement mortar were investigated.It has been shown that the flow of modified mortar is increased with increasing polymer-cement ratios,and change with increasing GMA content.The four kinds of latex will markedly reduce capillary water absorption rate,and will influence much on the mechanical properties of modified mortars.The compressive strength of PB-g-PSG is decreased with increasing mp/mc,which is lower than control mortar.The flexural strength of polymer modified mortars are increased with inc reasing mp/mc at mp/mc lower than 10%,which is higher than control mortar.The maximum of flexural strength of polymer-modified mortar is 9.65 MPa.PB-g-PSG latex can be incorporated into cement mortar s as cement modifier.