Effects Of Solvent Composition And Polymer Concentration On Poly (Ethylene Terephthalate) Degradation In Phenol: 1,2-Dichlorobenzene Blended Solvent

Abstract

Poly (ethylene terephthalate) was evaluated for its acid number, ash content and melting temperature, and were found to be 2m mol COOH/Kg, 0.0037% and 260-2630C respectively. Its solution in Phenol: 1,2-dichlorobenzene solvent mixtures of 35%: 65%, 50%: 50%, 65%: 35% by weight was degraded at 143± 2oC. The effects of solvent composition and polymer concentration on poly (ethylene terephthalate) degradation in solution were investigated by dilute solution viscometric method using 0.460, 0.500 and 0.540 g/dl polymer concentrations, respectively. Results indicate that at 35%: 65%: by weight Phenol: 1,2-dichlorobenzene solvent composition, intrinsic viscosity–degradation time profile was linear with slopes of 2.50x10 -4 , 3.10 X 10 -4 and 3.33 X 10 -4 and dlg -1 min -1 for polymer concentrations of 0.460, 0.500 and 0.540 g/dl respectively. This showed that the rate of degradation increased with increase in polymer concentration. Similar results were obtained for 50% Phenol: 50% 1,2-dichlorobenzene solvent mixture but with an initial high rate of degradation within the first 60 minutes of degradation time. At 65% phenol concentration, a decrease in the rate of degradation as the polymer concentration increased was observed as evidenced by a decrease in the slopes of the linear plots from 3.06x10 -4 dlg -1 min -1 to 2.63x10 -4 dlg -1 min -1 for a decrease in polymer concentration from 0.500 g/dl to 0.460g/dl. KEY WORDS: Poly (ethylene terephthalate), Degradation, Solution Viscometry. Global Journal of Environmental Sciences Vol.3(1&2) 2004: 59-64