有机硅改性红层泥岩表面疏水机理  

Mechanism of surface hydrophobicity of red-bed mudstone modified by organosilicone

作　　者：周雨晴 陈晓斌[1,2] 程玉峰 吴梦黎 张家生[1,2] 喻昭晟 ZHOU Yuqing;CHEN Xiaobin;CHENG Yufeng;WU Mengli;ZHANG Jiasheng;YU Zhaosheng(School of Civil Engineering,Central South University,Changsha 410083,China;MOE Key Laboratory of Engineering Structures of Heavy Haul Railway,Central South University,Changsha 410083,China;Guangdong Huiyang Architectural Design Institute,Huizhou 516200,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410083 [2]中南大学重载铁路工程结构教育部重点实验室,湖南长沙410083 [3]广东省惠阳建筑设计院,广东惠州516200

出　　处：《中南大学学报（自然科学版）》2023年第12期4828-4838,共11页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51978674);中南大学中央高校基本科研业务费专项资金资助项目(2023ZZTS0630)。

摘　　要：采用有机硅对红层泥岩进行表面疏水改性以抑制毛细作用。首先,通过接触角试验初步探寻有机硅改性前后红层泥岩疏水性质变化规律;其次,通过扫描电子显微镜(SEM)从微细观角度揭示有机硅改良红层泥岩疏水性的机理;最后,通过毛细吸水试验,明确抑制红层泥岩毛细水作用的最佳有机硅改性质量分数。基于仿生学理念,在红层泥岩表面构建了有机物疏水涂层。研究结果表明:掺入有机硅能大幅提升红层泥岩表面疏水性能,当有机硅质量分数wo达到0.4%以上时,可将亲水表面变为疏水表面;接触角随有机硅质量分数增加而呈现先增大后缓慢减小至稳定的特征;在有机硅质量分数为1.0%时,红层泥岩表面接触角取得最大值136.5°,此时,表面自由能达到最小值4.44 mN/m,呈现最佳疏水效果;毛细水上升速度与毛细吸水质量增长速度均随有机硅质量分数增加而显著降低。当有机硅质量分数≥2.0%且吸水7 d时,毛细水上升高度不超过5 mm,能抑制土体对水分的吸收,兼具经济性与毛细水阻隔效果的最佳质量分数为2.0%。有机硅通过与水和CO_(2)反应在其表面生成聚甲基硅烷长链,包裹土颗粒形成仿生疏水薄膜。成膜作用、孔隙中K+吸附作用及—Si—O—Si—键团聚作用共同提高了红层泥岩表面的密实度及疏水性能。Surface hydrophobic modification of red-bed mudstone was carried out with organosilicone to inhibit capillarity.Firstly,the contact angle test was carried out to investigate the change of hydrophobic properties of redbed mudstone before and after organosilicone modification.Secondly,scanning electron microscopy(SEM) was carried out to reveal the mechanism of hydrophobicity improvement of red-bed mudstone by organosilicone.Finally,through capillary water absorption test,the best organosilicone modified mass fraction to inhibit capillary water of red-bed mudstone was determined.Based on the concept of bionics,an organic hydrophobic coating was successfully constructed on the surface of red-bed mudstone.The results show that the incorporation of organosilicone can greatly improve the hydrophobic performance of red-bed mudstone surface.The hydrophilic surface can be changed to hydrophobic surface when the mass fraction of organosilicone(wo) is above 0.4%.With the increase of wo,the contact angle first increases and then slowly decreases until it becomes stable.When wo is 1.0%,the maximum value of contact angle is 136.5°,and the surface free energy reaches the minimum value of 4.44 mN/m,showing the best hydrophobic effect.Capillary water rising rate and capillary water absorption mass increasing rate decrease significantly with the increase of wo.When wo≥2%,the rising height of capillary water is not more than 5 mm by 7 d,which can inhibit the absorption of water by soil.The best mass fraction with both economic efficiency and capillary water barrier effect is 2.0%.Organosilicon reacts with water and CO2 to generate polymethylsilane long chains on its surface,which wraps the soil particles to form a hydrophobic film.Film formation,K+ adsorption and —Si—O—Si— bond agglomeration jointly in pores improve the compactness and hydrophobic properties of red-bed mudstone surface.

关 键 词：红层泥岩 有机硅改性 接触角 毛细水上升高度 疏水机理 

分 类 号：TU442[建筑科学—岩土工程]