Process Behavior and Application of Dynamic Self-Adjusting Water-Transferring Composite Coat

Abstract:

A kind of dynamic water-release composite coated fiber used for water saving afforestation in desertification area is prepared. The coat is composed of polyacrylamide and montmorillonite grains with an appropriate proportion. TG/DTA thermal analyzer is used to study coat water adsorption-desorption performance. Rapid moisture tester is used to analyze the water-releasing characteristic of the coat in different temperature and different soil moisture. Environmental scanning electron microscope (ESEM) is used to observe coat surface morphology. Finally, the water-transferring mechanism is studied. The results show that polyacrylamide and montmorillonite grains have a great influence on the water retention property and water permeability of the coat, respectively. Water-transferring rate of the coat can be effectively improved by designing the proportion of polyacrylamide and montmorillonite grains. Water potential influences the water-transferring rate significantly. When the outside soil inclines to be droughty or the temperature is going up, water potential of soil is lower than the potential of the coat, polyacrylamide shrinks with dehydration. Montmorillonite grains bridge together and in the state of “bridge-connection”. Water is transferred quickly along the channels of grains and water-transferring rate of the coat accelerates. When soil is getting wet or temperature is going down, water potential of soil is higher than the potential of the coat, polyacrylamide swells because of high water-potential. Montmorillonite grains split and in the state of “bridge-break”. Water is transferred slowly relying on the absorption-desorption of polyacrylamide and water-transferring rate decreases. So the composite coat can self-adjust soil moisture to guarantee plants survival and make full use of water resources.

• Periodical: Materials Science Forum (Volume 685)
• Pages: 253-259
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.685.253
• Online since: June 2011
• Authors: Zengzhi ZHANG, Hong Mei Du
• Keywords: Desertification, Ecological Construction, Water Potential, Water-Release Coated Fiber

References

[1] CCICCD. China country paper to combat desertification. Beijing: China Forestry Publishing House(1996), p.18.

[2] Zhao J, Zhang Z Z, Zhang L M, et al. Preparation and Water-Releasing Characteristics of Water-Conducting Fiber Coating with Flyash. Journal of Functional Materials, vol38, (2007), p.809.

[3] Kang Y H, Ma X Y, Li J, et al. Research and Development on Subsurface Drip Irrigation Technique. Journal of Irrigation and Drainage, vol26, 6 (2007), p.34.

[4] Ma T X, Pang Z C, Lu X Z. Research status and prospect on application of water holding agent in watersaving agriculture. Journal of Gansu Agricultural Science and Technology, vol12, (1997), p.31.

[5] Wang J L. A series of studies on the application of Super Absorbent Polymers in the low mountain and sunny slope afforestation of Beijing. Journal of Beijing Forestry University, 13(Supplement I), (1991).

[6] YIN G P, NONG R G, LIU G N. Advances in the research and utilization of water-absorbing poly- mer in forestry in China. Journal of World Forestry Research, vol14, 2, (2001), p.50.

[7] WANG J L. A series of studies on the application of sopper in the low mountain and patch reforestation( I, II, III, IV). Journal of Beijing Forestry University, 13(Supplement I), (1991).

[8] Zhou P, Li J Y, Yang Q L. A Study on the Moisture-Releasing Patterans and Characteristics of Solid Water. Journal of Scientia Silvae Sinicae, vol38, 5(2002), p.18.

[9] Zhou P, Li J Y, Yang Q L. The effect of solid water on seedlings. Journal of Beijing Forestry University, vol24, 1, (2002), p.16.

[10] Tinus R W and Mc Donald S E. How to grow tree seedling in containers in greenhouse, USDA Forest Source, General technical report RM60, (1979).

[11] Feng J C, Deng G B, He W, et al. Progress and Prospects for Application of Antitranspirant in Forestry. Journal of Forest Research, Vol. 18, 6, (2005), p.755.

[12] Zhang Z Z, Zhang L M, Ma X D, et al. Controllable Water-releasing Mechanism of Water-releasedly Coated Fiber. Journal of materials engineering, 7, (2008), p.25.