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Abstract A superabsorbent hydrogel (product I) was prepared through polymerizationof acrylic acid/acrylate under potassium persulphate initiation and methylene-bisacrylamide as a cross-linker. The effect of variation of initiator (KPS), crosslinker (MBAAm) doses and AAc/KOH ratio were investigated related to the swelling behaviour of the prepared SAH under investigation. The optimum conditions to obtain maximum swelling ratio 230 g/g were AAc/KOH ratio, 0.9 mole/mole; KPS, 0.4gand MBAAm, 0.01g. Superabsorbent hydrogel were prepared using the optimum condition in a bench scale and the yield was about 90.8 %. The total profit/year is $ 30312 and SRR% is 67 % for 18 tons SAH/annual supposing SAH selling $ 3300/ton (lowest world price ) and the payback period 3 years. Positive economic indicators have been obtained. Thus in view of experimental results and economic assumptions there are positive prospects for production of SAH under Egyptian conditions. Production cost of hydrogel can be decreased with increasing production capacity/year which increases gross profit and decreases payback period. CMC -g- poly (AAc -co-AAm) superabsorbent hydrogel (product II) were successfully prepared via a free radical copolymerization. Preparation factors such as CMC/AAc/AAm ratios, cross-linker density and initiator dosewere also investigated. The swelling characteristics of the resulting hydrogel were evaluated. Swelling capacity was found to be related to swelling duration and pH. The obtained SAH has an optimum swelling ratio 190 g/g. At the first 90 minutes kinetic studies of swelling behavior was found to be in agreement with experimental data and the diffusion of these hydrogels was of the non-Fickian type. While as for longer swelling time the density of the sample has increased and causes a regular diffusion of water into the hydrogel. Vegetative growth and yielding of green peas plants grown in sandy soil amended with SAH were improved even under drought compared with that grown in sandy soil only under drought or full irrigation. 86 The effects of SAH on physiological changes, growth and yield of squash, Faba bean and Green Beas plants and subjected to drought stress were examined. Seeds of these plants were sown in pots containing mixtures of sand and different levels of SAH (0.1 to 0.9 %). SAH levels resulted in increasing the soil water potential which can be attributed to the enhancement of soil water holding capacity compared to control plants which had the lowest level of soil water potential. Increasing doses of SAH improve plants germination. So comparing each plant with the control one (0 % SAH) it is clear that presence of SAH enhanced the plants germination. Plant growth parameters including plant height, number of leaves, leaf area were improved by hydrogel treatments. |