The effects of ultraviolet irradiation on mass transport and mechanical properties of poly(methyl methacrylate) / multiwalled carbon nanotubes composites

• Main Authors: Hsu, Je Chuan, 許哲銓
• Other Authors: Lee, Sanboh
• Format: Others
• Language: en_US
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/98699134272694046177

碩士 === 國立清華大學 === 材料科學工程學系 === 103 === The interaction between solvent and PMMA had been studied for several decades. The mass transport of amorphous polymer in organic solvent can be classified as three types: (1) Case I transport, (2) Case II transport and (3) anomalous diffusion. Most polymers in solvent are anomalous transport which combines Case I and Case II transport. Harmon et al. excogitated a theoretical model which was applied successfully to PMMA specimen of finite size. We use Harmon model to fit the mass transport of methanol and CNTs/PMMA composites. The characteristic parameters of diffusion coefficient (D) and velocity (v) are calculated from the data of curve fitting, and satisfy the Arrhenius equation. At larger content of CNTs, the composites have higher rate of mass transport, which can be confirmed from the larger value of D and v. And it explains that the solvent methanol is easier to penetrate into the polymers with carbon nanotubes. The photochemical defragmentation reactions of poly(methyl methacrylate) (PMMA) by UV-illumination are mainly-classified as main chain scission, complete or incomplete side chain cleavage and direct UV-depolymerization. From the previous studies, it has been confirmed that UV irradiation degrades mechanical and optical properties of PMMA. After adding carbon nanotubes into PMMA becoming nanocomposites, we wanted to investigate the effects of UV irradiation on the CNTs/PMMA nanocomposites. Thus we study the relation between mass transport of PMMA with different contents of CNTs, and expose these CNTs/PMMA composites to UV irradiation. Through observing the change of mass transport, UV irradiation has much impact on the pure PMMA. The rate of mass transport increases rapidly after irradiation. In contrast, the CNTs/PMMA composites exhibit less degree of UV irradiation effect from the slightly change of mass transport.