No abstract

Poly(vinyl alcohol) (PVA) films with different thicknesses (0.08, 0.2, 0.23, 0.42 mm) were prepared by a casting technique. The transmission and the absorption of the PVA films were measured as functions of the wavelengths. PVA film with a thickness of 0.42 mm showed zero transmission in the wavelength range of 190 -350 nm. The transmission spectrum of a commercial polyethylene film with a thickness of 0.21 mm was compared to the transmission spectrum of PVA film with a thickness of 0.42 mm. A correlation was found between the two transmission spectra in the region 190 -350 nm and a 20% increase in the transmission of the PVA film in comparison with the transmission of commercial polyethylene in the region 350 -1500 nm. The near-infrared region of the transmission of commercial polyethylene was increased by 15% with respect to the transmission of the PVA film. The stress-strain measurements were done for PVA and commercial polyethylene films. The Young's modulus and the strength at break for PVA films are higher by two orders of magnitude than those for commercial polyethylene film. The strain at break for commercial polyethylene is 17% lower than that for PVA film. Radiation effects on the optical properties of PVA and commercial polyethylene films were investigated. The PVA and commercial polyethylene films were irradiated with a xeon arc lamp at 3.5-5 W/cm 2 . The optical properties for PVA and commercial polyethylene films were studied after irradiation. The obtained results showed that PVA film with a thickness of 0.42 mm gave promising properties which could be used in technological applications.

ABSTRACT:The effects of ultraviolet (UV) radiation and thermal annealing on the optical and mechanical properties of polyvinyl alcohol (PVA) were studied. Pure PVA samples were prepared by casting technique. Xenon arc lamp was used to irradiate the sample. The irradiated PVA sample was heated at 150°C for 2 h. The optical and mechanical properties of original, irradiated, and irradiated and then heated samples were measured. The irradiated and then heated sample showed lower transmission in the wavelength range from 190 to 320 nm and the transmission was higher in the visible region than the original and irradiated samples. The stress-strain measurements were performed. Modulus of elasticity of the double-treated sample was approximately four times higher than that of original sample. The obtained results show the possibility of using this sample as cut-out filter for UV radiation.