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Abstract
New polymer is obtained by polymerization of a-Naphthol by EI-Garf ’s developed method with molar ratio of a- Naphthol: AlCi):FeCi).6H20 (1:1:2) at 100°C and for 4 hours ,which are the optimum conditions for polymerization of a naphthol.
. The polymer is studied by Ff -IR which shows that the suggested structure is poly (1¬hydroxy 2, 4 naphthalene) .The mechanism of the polymerization reaction is proposed to be radical-cationic polymerization.
DTA shows principal exothermic peak which begins at 389°C and ends at 869°C with an average peak at 525.65°C, which is due to drastic decomposition. Before this temperature there is no exothermic decomposition. The exothermic peak is due to decomposition because TGA shows decomposition at this temperature. This means that this peak is not due crysta1lization. DTA does not show any endothermic peaks. This means that the polymer does not show any endothermic peaks, this means that there is no melting .TGA in nitrogen atmosphere shows that maximum decomposition of (PAN) polymer begins at 222.44 °C and ends at 669.62 °C with an average value of principle exothermic peak of 519.07°C .At 1005 QC, the polymer completely decomposed. TGA in air shows a peak at 5625 °C which is less than that of nitrogen with 48°C which is not considerable. This peak represents evaporation of water vapor from the polymer. It begins at 21°C and ends at 112.5°C. The percentage weight loss due to evaporation of water is 14.915 % which corresponds to the percentage humidity in our polymer. It also shows that the polymer has an average value of principal exothermic peak of 471°C. At 620.3 °C the polymer will be completely decomposed. The total percentage weight loss from room temperature to 620.3°C is 99.717%. Thus the total percentage weight loss after subtraction of water loss is 84.802 %.
The radiation absorption of pure (PAN), it’s composite with zinc and it’s coated with polystyrene are studied. It was found that the mass absorption coefficient of pure (PAN) is higher than that of lead by 26.9 times when considering the reported value in the literature and by 17.3 times when considering the measured value under the same conditions. Depending on the percentage of zinc (PAN) -zinc composite has a mass absorption coefficient higher than that of lead in the range {)f 24.64 - 26.4 times (based on the reported value of lead), and in a range of 15.86 - 17 (based on the measured value of lead),
. which is about the same value for pure (PAN) within experimental error, so the composite that contains [10010 (PAN) + 90% Zinc] is the most efficient and economic for radiation shielding. Coating the (PAN) with polystyrene has no practically effect on its mass absorption coefficient but it gives strength to the discs even using almninum foil or without using aluminum foil.
’i. Generally, the aluminum foil has no practically effect on the mass absorption
coefficient of (PAN). This Means that (PAN) can absorb both ., and P ray with the same . effectiveness beside absorption of., ray. (PAN) polymer is the best choice as a radioactive ’:shield material. has the highest value of mass absorption coefficient, which is higher than ,tbat of other polymers prepared by the same method as our plepared polymer(El-Garfs ~4kveloped method).