Characteristics Evaluation of the Multifunctional Sand-fixing and Water-maintaining Polymer

Desertification of lands is one of the most serious ecological problems in China. Three mature methods, namely engineering sand-fixing, biological sand-fixing and chemical sand-fixing, can be applied to control and recover the desert. Former two not only take time and effort but alsocapital intensive. Therefore, chemical approaches aimat sand- fixing, water-maintainingand nutriments-offering have been an alternate option. In this paper, three types of multifunctional sand-fixing and water-maintaining polyme(r humus- plastic polymer, plastic-starch polymer and air-slake coal polymer) , which could provide nutriments, fix sand, preserve water, remediate soil and recover desert, were made from the air- slake coal and the abandoned plastics by liquid chemical method, emulsification, high velocity cutting method and mixing in non- homogeneous solution. The characteristics of the polymers such as particle size distribution, viscosity, anti-press intension, freeze- thawcapacity, aging capacity and anti-windy capacity was analyzed to select one polymer with excellent sand-fixing and water-maintaining characters. The results indicated that all three types of polymer not only decreased water evaporation under no vegetation, for example, in 15 days the control evaporated 99.8%, while three types polymer evaporated 98.2%, 98.1% and 97.4% in 50 days respectively, but also increased moisture content with vegetation, for example, after 60 days of seeding, water content in soil was 8.33% ,14.33%,15.45% and 16.35% respectively. And air-slake coal polymer was the best one with integrated analysis as follow: the diameter of the particles was in the scope of 20 nm to 60 nm, the anti-press intension of concretion was 5.30 MPa to 16.10 MPa, and the effect of anti-gelation and anti-weathering were significant. Additionally, the function ofanti-wind erosion was strong, for that nodust and erosion occurred when the wind blown continuously at 25 m·min-1 for 30 min and 30 m·min-1 for 5 min, respectively. Therefore, air-slake coal polymer was the optimum one to provide nutri-ments, fixsand, preserve water.