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Transport Kinetics of Methanol in Hydroxyethyl Methacrylate Homopolymer and Its Copolymers



C-S Tsai, S H. Lee, Tinh Nguyen


The kinetics of methanol transport in 2-hydroxyethyl methacrylate (HEMA) homopolymer and 75/25 and 50/50 mole fraction HEMA/DHPMA (2,3-dihydroxypropyl methacrylate) copolymers at five different temperatures has been investigated using the sorption experiment technique. A combined Case I and Case II diffusion model was employed to describe the transport processes. Four replicates for each temperature of each material having a nominal thickness of 0.1 mm were immersed in methanol maintained at (35, 40, 45, 50 and 55) oC, and the mass uptake as a function of time was measured gravimetrically. Experimental results are found to be in good agreement with model prediction at all temperatures and for all three materials. Both the diffusion coefficients of Case I transport and velocity of Case II transport increase with increasing temperature. D values at low temperatures (35oC and 40oC), which are in the 10-9 cm2/sec range, of the HEMA homopolymer are higher than those of the copolymers. On the other hand, the activation energies of Case I transport of the copolymers are substantially higher than those of the HEMA homopolymer; however, the level of DHPMA loading in the copolymer does not seem to affect the activation energy. In addition, thermodynamic heat and free energy of mixing values indicate heat is released when HEMA/DHPMA copolymers are exposed to methanol and that the solvent/copolymer systems exist as a continuous phase. In contrast, the methanol/HEMA homopolymer system exists as separate phases.
Journal of Materials Research


Building Tecnology, HEMA copolymers, HEMA polymers, kinetics, methanol, transport


Tsai, C. , Lee, S. and Nguyen, T. (2021), Transport Kinetics of Methanol in Hydroxyethyl Methacrylate Homopolymer and Its Copolymers, Journal of Materials Research (Accessed April 24, 2024)
Created October 12, 2021