الفهرس 
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Abstract
The aim of the present work is to prepare new polymeric dosimeter systems with remarkable new properties of color-changing and excellent response to gamma radiation in a wide range of doses.
Polyanilines Gamma Dosimeter Systems
In this part, we focused on studying the response of polyaniline and its derivatives to radiation exposure through its presence in different polymeric systems. The first system consists of a polyaniline/gelatin polymer solution, where its color changes from violet to blue, green, pale green, and finally into yellow, on its exposure to gamma radiation the results obtained from the absorption spectra, response curves, sensitivity, G-value, and show that the energy gap decreases with increasing radiation dose. The stability of the dosimeter before and after irradiation under different storage conditions in an indirect light and dark was also studied. It was found that the dosimeter has good stability before and after irradiation. The applied dose range was from 0 to 25 kGy.
Hammett’s equation was applied using polyaniline and its with electron attracting and electron donating substituents derivatives, where the absorption spectra of polyaniline and its derivatives were studied, and show a gradual decrease in band intensity with increasing radiation except with poly 4-chloroaniline where it decreases. The effect of radiation in a uniform condition of pH, concentration and temperature is studied. Hammett equation was verified by plotting log (k/k0) against radiation doses, gave a linear plot with ρ value (+1.143) indicating that the reaction enhances with electron donating substituents and the mechanism of the reaction involves the formation of transition state with a positive center, that is stabilized by electron donating substituents
The order of their efficiency as dosimeters falls in the following order:
4-methoxyaniline> 4-hydroxyaniline > aniline > 4-chloroaniline
Moreover, polymeric system polyaniline hydrogel that has been prepared from polymeric mixture containing natural polymer (gelatin and Carboxymethyl cellulose (CMC)) in addition to polyvinyl alcohol (PVA). The noticeable color change was in the same way as the previous liquid system, which shows great sensitivity to radiation
with excellent stability, the morphology of the prepared hydrogel indicates the increments of crosslinking with increasing radiation dose. By comparing the two prepared systems of polyaniline (solution – hydrogel), The procedure of making a solution-based gelatin system is very easy showing good stability for about two months. while hydrogel lasts much more than two years and is more sensitive. The sensitivity of the hydrogel to radiation increases with increasing aniline initial concentration, while in the case of the solution decreases.
Development of Hydrogel Dosimeter for Industrial Use in Low Dose Gamma Dosimeter Application
We studied the application of natural polymers in dosimeter systems due to their large response and sensitivity to radiation, and aimed to improve the response and accelerate dye degradation using natural polymer .In this system Congo Red (CR) dye was added to hydrogel system (gelatin/carboxymethyl cellulose) with increasing radiation dose, the dissolution of the dyes increases and thus the color of the prepared hydrogel changed from orange to colorless due to dye degradation, which confirms the response to the radiation dose. The ultraviolet (UV) measurement showed a gradual decrease in band absorbance with increasing radiation also the FTIR data emphasized the degradation process so that the bands were mostly disappeared after radiation exposure. the stability before and after irradiation for the hydrogel was investigated in dark and light, as it was found that the prepared hydrogel has good stability before and after irradiation throughout the study period It was found that the prepared hydrogel has a response in the range of 0 to 5. 3 kGy, in addition to the fact that they can be prepared in laboratories with no use of toxic solvents.
We Prepared the dyed hydrogel systems containing 2,6-dichlorophenolinophenol (DCP) prepared based on a polymeric mixture consisting of carboxymethyl cellulose, gelatin, and polyvinyl alcohol (PVA / gelatin / CMC) with a volume ratio of (1:1:1) of their prepared solutions. The degradation of the dye upon exposure to radiation results in a gradual disappearance of the blue color, and the spectral result indicated the decay of the dye, spectral properties, dose-response, radiation sensitivity, and stability before and after irradiation. UV measurement showed a gradual decrease in band absorbance with increasing radiation also the FTIR data confirmed the degradation process where there was a decrease in bands after radiation exposure. The applicable dose was in the range zero to 1000 Gray, which is suitable for food sterilization applications.
Low Dose Films Dosimeter Based on a Mixture of Dyed Poly Vinyl Alcohol
The polymeric membranes based on two mixtures of dyes in presence of a polymeric medium of polyvinyl alcohol in the form of films has been synthesized. The effect of gamma radiation on the films that are consisting of polyvinyl alcohol with dyes mixture are studied, first film is consisting of poly vinyl alcohol with2,6-dichlorophenol indophenol and bromophenol red dye (BPR-DCP) / PVA upon radiation exposure, the color of the film changed from green to yellow In the dose range of 0-40 kGy without the addition of chloral When adding chloral which accelerates the radioactive response as it releases HCl when exposed to radiation, the dose range was from 0 to 20 kGy. The dosimetric properties of the films were examined by spectrophotometry, which shows great stability before and after irradiation (in the light) along with the effect of relative humidity, which results showed a slight change in spectrophotometry under the influence of humidity to the range of 70% of relative humidity It is possible to use this dosimeter in the field of sterilization of medical products and devices.
The second was the mixture of dyes 2,6-dichlorophenolindophenol with Congo red dye (CR-DCP)/PVA). Under the influence of gamma rays, the color of the film changes from violet to pink, applied in a dose range from 0 to 80 kGy without adding chloral and from 0 to 40 kGy by adding chloral. These films show good stability and ease of handling which made them a good choice for routine work. The dosimetric properties of the films were examined spectrophotometry, which shows great stability before and after irradiation (in dark light), and are not affected by relative humidity changes in the range of (10% -76%). These films are easy to be made and thus, amenable for large-scale production and application for Material modification routine irradiation process of food and medical devices Sterilization.