抗水性聚丙烯酸酯类土壤固化剂的制备及性能

Preparation and properties of water-resistant polyacrylate soil curing agent

以丙烯酸丁酯(BA)和丙烯酸(AA)为原料,以十二烷基硫酸钠(SDS)和烷基酚聚氧乙烯醚(OP-10)为复合乳化剂,合成一种纯丙类乳液土壤固化剂PAA;为了提高其抗水性,聚合中引入苯乙烯(St)单体,制得聚丙烯酸酯类土壤固化剂PAAS,合成工艺均采用预乳化半连续种子乳液聚合法;采用FTIR对其结构进行表征,同时对合成乳液的粒径进行测试;对固化土/水表面接触角进行测试;然后研究在不同固化剂掺量及养护龄期条件下,土壤固化剂对重塑土无侧限抗压强度的影响。结果表明,合成的乳液粒径分布均匀,分散性好;未掺固化剂所压土片与水接触直接润湿,而掺入固化剂所压土片接触角明显增强,且掺入固化剂PAAS使得固化土/水界面瞬间接触角增长至99.78°,其疏水性较强;随固化剂掺量的增加或养护龄期的延长,土壤固化剂对重塑土强度有明显增强效果;当养护龄期为3 d,PAAS固化剂掺入量为0.08%,其无侧限抗压强度增长至265.8 kPa;在养护龄期为3 d,固化剂掺量为0.08%时,改性土试样抗压强度相对空白样而言相对增量最大,且PAAS改性土强度相对增量达1.08倍。

Using butyl acrylate(BA)and acrylic acid(AA)as raw materials,and using sodium dodecyl sulfate(SDS)and alkylphenol polyoxyethylene ether(OP-10)as composite emulsifiers,a pure acrylic emulsion was synthesized soil curing agent PAA;in order to improve its water resistance,styrene(St)monomer was introduced into the polymerization to obtain polyacrylate soil curing agent PAAS.The synthesis process adopts the pre-emulsification semi-continuous seed emulsion polymerization method;its structure was characterized by FTIR,and the particle size of the synthetic emulsion was tested at the same time;test for contact angle of cured soil/water surface;then the effect of soil stabilizer on the unconfined compressive strength of the reshaped soil was studied under the conditions of different curing agent dosage and curing age.The results show that the particle size distribution of the synthesized emulsion is uniform and the dispersibility is good;the soil sheet without curing agent directly wets in contact with water,while the contact angle of the soil sheet with curing agent increases significantly,and the addition of the curing agent PAAS makes the instantaneous contact angle of the cured soil/water interface increase to 99.78°,and its hydrophobicity is strong;with the increase of the content of the curing agent or the prolongation of the curing period,the soil curing agent has a significant enhancement effect on the strength of the reshaped soil;when the curing age is 3 d and the content of PAAS curing agent is 0.08%,its unconfined compressive strength increases to 265.8 kPa;when the curing age is 3 d and the dosage of curing agent is 0.08%,the relative increase of the compressive strength of the modified soil sample is the largest relative to that of the blank sample,and the relative increase of the strength of the PAAS modified soil is 1.08 times.