文章信息/Info

Title:

Water-conducting Composite Material and its Self-adjusting Effect on Soil Moisture

作者:

杜紅梅; DU Hongmei ; ZHANG Zengzhi

Research Institute of Ecological and Functional Material, China University of Mining & Technology, Beijing

關(guān)鍵詞:

土地荒漠化; 節(jié)水造林 ; 復(fù)合涂層;  水勢(shì)梯度;  導(dǎo)水機(jī)理

Keywords:

desertification;  water saving and afforestation;  composite coating;  water potential gradient;  water-conducting mechanism

DOI:

10.7502/j.issn.1674-3962.2017.11.01

文獻(xiàn)標(biāo)志碼:

A

摘要:

制備了一種用于荒漠化地區(qū)節(jié)水造林的水分子滲灌復(fù)合導(dǎo)水材料。該材料采用分子滲水的方式進(jìn)行供水，大大節(jié)省了水資源，實(shí)現(xiàn)了水分的最有效利用。采用紅外光譜方法研究了復(fù)合材料的官能團(tuán)變化；采用SEM和ESEM分析了材料的微觀結(jié)構(gòu)和不同水勢(shì)下的動(dòng)態(tài)行為；通過導(dǎo)水能力試驗(yàn)測定得到了材料的l-t曲線；通過不同溫度/濕度下的失水率/含水率試驗(yàn)得到了材料在外界條件變化下的導(dǎo)水規(guī)律。最后對(duì)復(fù)合導(dǎo)水涂層材料的動(dòng)態(tài)導(dǎo)水機(jī)理進(jìn)行了分析和討論。結(jié)果表明：復(fù)合材料的導(dǎo)水速率隨著材料中蒙脫石含量的增加而增大。通過調(diào)節(jié)蒙脫石與聚丙烯酰胺的配比可調(diào)整材料的導(dǎo)水速度。材料的導(dǎo)水速度隨外界溫度的升高而增大，隨著外界濕度的增加而減小。導(dǎo)水涂層材料的導(dǎo)水機(jī)制與水勢(shì)及水勢(shì)梯度密切相關(guān)。在高水勢(shì)下，蒙脫石顆粒斷橋，水分由聚丙烯酰胺傳導(dǎo)，導(dǎo)水速度慢；在低水勢(shì)下，蒙脫石顆粒橋接，水分經(jīng)蒙脫石顆粒間的導(dǎo)水通道傳導(dǎo)，導(dǎo)水速度快。沿著導(dǎo)水涂層纖維，形成了水勢(shì)梯度差，水分從高水勢(shì)向低水勢(shì)進(jìn)行自發(fā)傳導(dǎo)。

Abstract:

A kind of 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 most effective. 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 behavior under different water potential was also studied. The l-t curves and 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 positively correlation with the montmorillonite content. The rate can be regulated by adjusting the mass ratio of polyacrylamide and montmorillonite. The rate was 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.