الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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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.
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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.