Sung-Woon Myung

Plasma-induced graft co-polymerization of acrylic acid onto the polyurethane surface

Abstract We introduced carboxylic groups on the surface of polyurethane (PU) with the aid of oxygen plasma treatment and the post-grafting of acrylic acid (AAc) in an aqueous solution. After plasma treatment, PU was exposed to the air to generate peroxides. Peroxides were confirmed by the 1,1-diphenyl-2-picrylhydrazyl method. We chose different parameters of plasma treatment to get the optimum condition for introducing maximum peroxides on the surface. Peroxides are known to be the species responsible for initiating the graft co-polymerization when PU reacts with AAc to produce AAc grafted PU. The AAc grafted on the surfaces was characterized by water contact angle measurement, Fourier transform infrared by attenuated total reflectance and electron spectroscopy for chemical analysis and optical microscopy. After confirming a successful grafting of AAc, we studied the effect of reaction temperature, reaction time, monomer concentration and Mohrs salt on the grafting degree of AAc.

Numerical and Experimental Study on the Biofiltration of Toluene Vapor

We have solved both steady state and transient problems on the biofiltration of toluene vapor. The effect of inlet toluene concentration and inlet gas-flow rate on the removal rate of toluene and the elimination capacity of a lab-scale biofilter has been investigated. In this study, the effectiveness factor was a function of pollutant concentration. The dynamic solutions show good agreement with experimental results. At an inlet toluene concentration of 100 ppm, the diffusion of toluene into biofilm was obviously a rate determining step. Above 200 ppm, however, biofilm already showed full activity. The steady-state simulation confirmed that the change of elimination capacity obtained by increasing only inlet toluene concentration was the same as that obtained by increasing only flow rate of contaminated air. The maximum possible performance is about 20 g/m3h with no addition of nutrients.