The effect of UV irradiation on evolution of solvent-induced surface pattern and color center in polymers

• Main Authors: Chang, Shun Chieh, 張舜傑
• Other Authors: Lee, Sanboh
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/88181311430259838982

碩士 === 國立清華大學 === 材料科學工程學系 === 103 === The effects of UV irradiation on polymer have been extensively studied. UV irradiation will change the physical and mechanical properties of polymer. We study on discoloration of poly(methyl methacrylate) and solvent-induced surface pattern of polycarbonate. At elevated temperatures, the transmittance of UV irradiated poly(methyl methacrylate) (PMMA) increases monotonically with increasing time. The optical absorbance data found in good agreement with the theoretical model in which annealable color centers follow a first-order kinetic process. The rate constant satisfies the Arrhenius equation, with the activation energies increased slightly with the increase of dose. After immersion/desorption/resorption processes in acetone solvent, polycarbonate becomes two regions: the swelling outer elastic layer and the glassy inner one. The swelling outer layer is constrained by the inner layer, which leads to a compressive stress. Periodic surface pattern forms during resorption. We study the effects of time, temperature, and UV dose on the swelling behavior. The morphology of the surface is observed by an optical microscope. The experimental results show that pattern wavelength increases with increasing temperature, absorption time, but decreases with increasing dose.