自调节土壤湿度的水分子控释复合导水材料  

Water-Conducting Composite Material and Its Self-Adjusting Effect on Soil Moisture

作　　者：杜红梅[1] 张增志[1] 

机构地区：[1]中国矿业大学(北京)生态功能材料研究所,北京100083

出　　处：《中国材料进展》2017年第11期807-812,共6页Materials China

基　　金：国家自然科学基金资助项目(50772131);国家"863"计划项目(2011AA322100);教育部重点项目(106086)

摘　　要：用聚丙烯酰胺和超细钠基蒙脱石制备了一种用于荒漠化地区节水造林的水分子渗灌复合导水材料。该材料采用分子渗水的方式进行供水,大大节省了水资源,实现了水分的最有效利用。采用红外光谱方法研究了复合材料的官能团变化;采用SEM和ESEM分析了材料的微观结构和不同水势下的动态行为;通过不同温度/湿度下的失水率/含水率试验得到了材料在外界条件变化下的导水规律,最后对复合导水涂层材料的动态导水机理进行了分析和讨论。结果表明:复合材料的导水速率随着材料中蒙脱石含量的增加而增大,通过调节蒙脱石与聚丙烯酰胺的配比可调整材料的导水速度。材料的导水速度随外界温度的升高而增大,随着外界湿度的增加而减小。导水涂层材料的导水机制与水势及水势梯度密切相关。在高水势下,蒙脱石颗粒断桥,水分由聚丙烯酰胺传导,导水速度慢;在低水势下,蒙脱石颗粒桥接,水分经蒙脱石颗粒间的导水通道传导,导水速度快。沿着导水涂层纤维,形成了水势梯度差,水分从高水势向低水势进行自发传导。A kind of water infiltration composite material used in desertification areas is developed. It supplies water in the way of molecular penetration, which makes the utilization of water resource to be the most effective way. The FTIR was used to study the changes of functional groups. The SEM and ESEM were used to analyze the composite coating＇ s microstructure, and its dynamic behaviors under different water potentials were also studied. The water-conducting pattern was obtained by the water-conducting experiment. Finally, the dynamic water-conducting mechanism of the composite material was studied. The results showed that the water-conducting rate had a positive correlation with the montmorillonite content, the rate can be regulated by adjusting the mass ratio of polyacrylamide and montmorillonite. The rate increased with increasing temperature and decreasing soil moisture. The water-conducting mechanism of the composite material was closely related to the water potential gradient. The high water potential was formed at the swelling end of polyacrylamide and the low water potential was formed at the end of connected MMT particles with polyacrylamide unswollen. When the coating was at low water potential, the montmorillonite particles connected and water was conducted quickly via montmorillonite layers, whereas when the coating was at high water potential, the montmorillonite particles disconnected and water was conducted slowly via the swelled polyacrylamide structure. The water gradient was generated along the coated fiber, thus water was conducted spontaneously.

关 键 词：土地荒漠化 节水造林 复合涂层 水势梯度 导水机理 

分 类 号：TQ326.4[化学工程—合成树脂塑料工业]