Synthesis and Characterization of Polymethylmethacrylate by Using Glow Discharge Electrolysis Plasma

Abstract

An approach for polymerization to produce polymethylmethacrylate (PMMA) was developed, in which the reaction was initiated by the glow discharge electrolysis (GDE) rather than chemical initiators. The highest number-average molecular weight (Mn) and the lowest polydispersity index (PDI) of the resulting polymer were 1.12 × 106 g/mol and 1.21, respectively. The following parameters such as the applied voltage, discharge time, the content of methylmethacrylate (MMA), the amount of a suspension stabilizer (polyvinyl alcohol), polymerization temperature and time were examined in detail, which could affect the conversion, molecular weight and polydispersity index. The Mn and PDI of polymer can be monitored by changing the discharge parameters and polymerization conditions. PMMA was characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), cold field emission scanning electron microscopy (FESEM), nuclear magnetic resonance (NMR) and thermogravimetric analysis (TGA). Results indicate that using the GDE technique to initiate the polymerization reaction is successful, because the product obtained has the same properties with one obtained by chemical method, for example, in chemical structure, tacticity and thermal stability. Moreover, the polymer particles for the former are smaller than the latter. The kinetic observation was that the polymerization of MMA initiated by the GDE plasma obeys the first order of reaction with an obvious induction period.