| Superabsorbent is an excellent water absorption and retention of new polymer materials, it is widely used in agriculture, health, construction and other fields since the development. Acrylic absorbent resins have strong absorption capacity, but salt resistance, strength is poor, water absorption of starch absorbent resin less well than the former, but it is can be biodegradable. This paper focused on synthesis process and preliminary applications of superabsorbent used in horticulture were studied. The results can provide reference in absorbent synthesis technology and application in horticulture.Using water solution polymerization, the optimum synthetic process parameters of polyacrylic acid absorbent resin (PAA absorbent resin), poly (acrylamide-co-acrylic acid) absorbent resin (P(AA-co-AAM) absorbent resin) and poly (acrylic acid-co-2-acrylamido-2-methyl propane sulfonic acid) absorbent resin (P(AA-co-AMPS) absorbent resin)in the laboratory have been obtained by using N,N’-methylenebisacrylamide (MBA) as crosslinking agent, potassium persulfate-sodium bisulfite (K2S2O8-NaHSO3) as initiator, acrylic acid (AA), acrylamide (AAM),2-acrylamide-2-methyl propane sulfonic acid (AMPS) as the monomers. And the optimum synthetic process parameters of potato starch grafted acrylic absorbent resin (St-g-PAA absorbent resin) by potato starch as the main graft backbone, AA graft monomer. The results showed that:1. The optimum synthetic process parameters of PAA absorbent resin are as follow:reaction temperature is 47℃, monomer AA accounts for the proportion of system is 26%, the amount of initiator, crosslinking agent are 0.15%,0.04%, respectively, based on the amount of monomer. The neutralization degree of acrylic acid is 85%. The reaction time in the bath is 180 min, cross-linking temperature is 125℃. At this time, water absorbent resin in water and 0.9% NaCl solution were 2445 g/g and 119 g/g, respectively.2. The optimum synthetic process parameters of P(AA-co-AAM) absorbent resin are as follow:monomer accounts for the proportion of system is 24%, the reaction time in the bath is 3.h, cross-linking temperature and reaction temperature are 125℃ and 47℃,respectively. The ratio of AA and AAM is 20:1, the amount of initiator, crosslinking agent are 0.10%,0.02%, respectively. The neutralization degree of acrylic acid is 80%. At this time, water absorbent resin in water and 0.9% NaCl solution were 1167 g/g and 77 g/g, respectively.3. The optimum synthetic process parameters of P(AA-co-AMPS) absorbent resin are as follow:monomer accounts for the proportion of system is 24%, the reaction time in the bath is 3.h, cross-linking temperature and reaction temperature are 125℃ and 47℃ respectively. The ratio of AA and AMPS is 15:1, the amount of initiator, crosslinking agent are 0.15%,0.05%, respectively. The neutralization degree of acrylic acid is 80%. At this time, water absorbent resin in water and 0.9% NaCl solution were 1703 g/g and 107 g/g, respectively.4. The optimum synthetic process parameters of St-g-PAA absorbent resin are as follow:the reaction time in the bath is 3.h, cross-linking temperature and reaction temperature are 125℃ and 55℃. The ratio of potato starch and AA is 15:1, the amount of initiator, crosslinking agent are 0.50%,0.10%, respectively. The neutralization degree of acrylic acid is 80%. At this time, water absorbent resin in water and 0.9% NaCl solution were 513 g/g and 60 g/g, respectively.Based on synthesis process, Yunnan red soil and mixed soil that mixed with red soil and organic soil as the main application object, investigated four absorbent resin in different water quality, different ions in solution, soil volume expansion, water retention capacity and the application effect of soilless cultivation. The results showed that:1. Due to the presence of electrolytes, PAA absorbent resin, P(AA-co-AAM) absorbent resin, P(AA-co-AMPS) absorbent resin and St-g-PAA’s water absorption capacity in water, tap water, laterite leaching solution, mixed soil leaching solution decrease successively.2. The larger ion concentration and ionic strength of the external solution exist, the smaller absorbent resin’s water absorbing capacity will be. Inhibition effects of water absorbing capacity by bivalent cation is seriously than monovalent cation in the external solution and inhibition effects of water absorbing capacity by electrolyte solution is seriously than nonelectrolyte solution.3. St-g-PAA absorbent resin, P(AA-co-AAM) absorbent resin and P(AA-co-AMPS) absorbent resin’s salt tolerance is stronger than PAA absorbent resin.4. The volumes of the red soil and mixed soil with water-absorbent resin were increased after absorbing water. With the increasing amount of water-absorbent resin, volume expansion ratio of soil increased, and the soil’s water holding capacity and water-holding capacity were batter.5. The artificial aggregate structure were formed when absorbent resin applied into the soil, and improved the permeability and water permeability of soil, therefore, soil became loose.6. The synthetic absorbent resin not only could be used as culture substrate of soilless culture, but also could increase the ornamental of plants.Based on the above research results, at the same time, the acrylic absorbent resin structures were characterized by means of infrared spectroscopy, thermal analysis, scanning electron microscopy. |
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