నైరూప్య

Effect Of Electron Beam Irradiation On Dispersion And Optical Constant Behavior For Polyurethane Sheets

S.M.El-Sayed and S.Abd El All

Radiation – induced polyurethane sheets have been investigated. The irradiation doses were conducted at the values 10, 30,60,90 kGy respectively. An ultra violet visible spectrophotometer (UV-VIS) was used to characterize the changes in the optical constants as a result of electron beam irradiation. The optical constants and the absorption coefficient of polyurethane sheets are determined from the reflectance as well as the transmittance. These parameters are related to the Fresnel interface reflectance and transmittance by the attenuation of light inside the sheet. The cross linking (induced by electron irradiation) limits the immovability of the polyurethane molecular chains, the refractive index, and the dispersion parameters were consequently subjected to a change. It increased with decreasing electron irradiation doses up to 90 kGy. At higher dose of irradiation (90 kGy), degradation of polyurethane rather than cross-linking was raised. The irradiation PU sheets indicated that the cross-linking and degradation are likely to have an effect on their dispersion parameters. ï›™ 2006 Trade Science Inc. - INDIA