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Makrofol DE 1-1 CC polycarbonate samples were exposed to alpha particles of initial energies at levels between 5.1 and 34 MeV. The modifications induced in polycarbonate samples due to the alpha particle irradiation have been studied through different characterization techniques such as X-ray diffraction (XRD), infrared spectroscopy, intrinsic viscosity, and color difference studies. The infrared spectroscopy indicated that the intensities of the characteristic absorption bands decrease with increasing the deposited alpha energy in the range 5.1-8.4 MeV, indicating that the degradation is the dominant mechanism at this range. At the same time, an increase in the À ÀOH groups was observed at the same energy range 5.1-8.4 MeV due to the degradation of carbonate group and the À ÀH abstraction from the polymer backbone to form hydroxyl groups. The degradation reported by IR spectroscopy enhanced the degree of ordering in the degraded samples as revealed by XRD technique. Additionally, this degradation decreases the intrinsic viscosity from 0.56 to 0.43 at 358C, indicating a decrease in the average molecular mass. The non irradiated Polycarbonate polymer is nearly colorless. It showed significant darkness sensitivity towards alpha particle irradiation, indicated by an increase in the color intercept L* from 33.6 to 36.7.

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Samples from sheets of the polymeric material Bayfol have been exposed to electron beam in the dose range 10-100 kGy. The resultant effect of electron beam irradiation on the thermal properties of Bayfol has been investigated using thermogravimetric analysis. The onset temperature of decomposition T 0 and activation energy of thermal decomposition E a were calculated, results indicating that the Bayfol polymer decomposes in one main weight loss stage. Also, the electron irradiation in the dose range 40-100 kGy led to a more compact structure of Bayfol polymer, which resulted in an improvement in its thermal stability with an increase in activation energy of thermal decomposition. The variation of transition temperatures with electron dose has been determined using differential thermal analysis. The results indicate that the electron irradiation in the dose range 40-100 kGy causes crosslinking that destroys the crystalline structure depressing the melting temperature and this is most suitable for applications requiring the molding of this polymer at lower temperatures. In addition, the mechanical and structural properties of Bayfol samples were measured and the results revealed that the tensile strength, elongation at break, yield strength, and intrinsic viscosity were affected by the electron doses.

: Samples from Cellulose triacetate (CTA) sheets were irradiated with electron beam in the dose range 10-200 kGy. Non-isothermal studies were carried out using thermogravimetric analysis (TGA) to obtain the activation energy of thermal decomposition for CTA polymer. The CTA samples decompose in one main break down stage. The results indicate that the irradiation by electron beam in the dose range 80-200 kGy increases the thermal stability of the polymer samples. Also, the variation of melting temperatures with the electron dose has been determined using differential thermal analysis (DTA). The CTA polymer is characterized by the appearance of one endothermic peak due to melting. It is found that the irradiation in the dose range 10-80 kGy causes defects generation that splits the crystals depressing the melting temperature, while at higher doses (80-200 kGy), the thickness of crystalline structure (lamellae) is increased, thus the melting temperature increases. In addition, the transmission of these samples in the wavelength range 200-2500 nm, as well as any color changes, were studied. The color intensity ,E* was greatly increased on increasing the electron beam dose, and accompanied by a significant increase in the blue color component.