الفهرس 
Chapter 1: IntroductionOnly 14 pages are availabe for public view
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Abstract
Water scarcity considered as one of the main challenges that facing the development activities in many semi-arid and arid regions globally. There were many reasons such as environmental pollution, population growth and climate change that led to water deficiency in many arid areas such as Egypt. A lot of trends were used to reduce the stress of the scarcity of water resources with dramatic population growth. So, applying superabsorbent hydrogels that had the massive features of keeping water was the best solution for reducing the effect of water scarcity that faces vulnerable arid areas. As, it is a continuous demand for developing high efficient superabsorbents materials with high water retention capability, rapid metal ions removal, reusable, and effective in cost, IPNs (Interpenetrating polymer networks) were applied as they possess these features. Also, as the removal of heavy metals is very important for environmental remediation, IPNs were used for removing copper metal ions at different concentrations.
The thesis was divided into three chapters, which included 68 illustration figures, 2 schemes, 17 tables, and 228 scientific references.
Chapter One: Introduction
The first chapter explained the problem of water shortage, types of water sources, types of wastewater pollutants and its treatment methods. It also described types of hydrogels, different synthesis methods, and its different types as super absorbent hydrogels and smart hydrogels, also types of polymer networks and their applications in the presence of castor oil.
Chapter two: Experimental
The second chapter explained the method of preparing (semi and Full) superabsorbent polymer networks using free- radical polymerization in the presence and absence of castor oil. The semi-interpenetrating polymer network was cross-linked using methylene bisacrylamide (MBA) and another crosslinker was added, which is glutaraldehyde (GA) to form a full interpenetrating polymer network. Also different techniques in characterizing chemical compounds were mentioned as well as studying water retention efficiencies of interpenetrating polymer networks under different environmental factors such as temperature, salinity, and pH and their ability to swell and release water several times. Also, method for removing different concentrations of copper metal ions as a heavy metal from the aqueous solution and studying its kinetic mechanism were mentioned. As well as Studying the mechanism of water swelling in the prepared hydrogels and studying the resistance properties of some selected hydrogels towards gram-positive and Gram-negative bacteria.
Chapter three: Results and discussion.
The third chapter included studying the mechanism of semi and full interpenetrating polymer networks based on castor oil and their structure were confirmed and correlated to their composition using some modern techniques such as ATR-FTIR, Raman spectroscopy, TGA, SEM, XRD, and AFM. The thermal properties were studied via TGA in order to investigate their stability and durability at high temperatures
The third chapter includes studying the following characteristics:
• First: The efficiency of the prepared materials were studied and their ability to trap water under various environmental conditions such as temperature, salinity and pH. The results showed that interpenetrating polymer network based on castor oil (F-4IPNC)) achieved the maximum water absorption (Qmax) under the following conditions, which are 25 °C , a neutral medium and saline-free solution with a pH of 7.
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• Second: The efficiency of interpenetrating polymer networks in swelling
and de-swelling several times and the data show the highest polymers in
absorbing and releasing water molecules were S-4IPNC and F-4IPNC that
show 6 cycles and 7 cycles respectively.
• Third: the kinetics of water absorption of the prepared hydrogels, the
results showed that they followed a pseudo second order and the highest
water absorption was for S-4IPNC and F-4IPNC with qe values (209 g/g)
and (249 g /g) respectively.
• Fourth: The ability of interpenetrating polymer networks in removing
different concentrations of copper metal ions (25ppm, 50 pm, 75 ppm and,
100 ppm) and the results show that S-4IPNC and F-4IPNC showed the
highest adsorption of copper ions at the concentration of 100 ppm with
Qmax values 99.4 mg/g and 99.836 mg/g respectively.
The best applied model used to describe the adsorption of copper metal
ions with different concentrations on IPN hydrogels was Langmuir
isotherm model. Also, the mechanism of water-swelling for prepared
hydrogels showed a Fickian character with n values less than 0.5.
• Fifth: The properties against Gram-positive and Gram-negative bacteria were studied, and the selected super absorbent hydrogels based on castor oil showed anti-bacterial activity towards gram-positive bacteria.
In conclusion, this work approved synthesis of potential eco-friendly superabsorbent hydrogels for water-saving applications in different fields