COMPARISON OF THE EFFECT OF DENSITY AND HYDROGEN-BONDING ON THE CLOUD-POINT BEHAVIOR OF POLY(ETHYLENE-CO-METHYL ACRYLATE) PROPANE-COSOLVENT MIXTURES

Cloud-point data to 170-degrees-C and 2800 bar (280 MPa) are presented for poly(ethylene-co-(31 mol%) methyl acrylate) at approximately 5 wt% in propane and in hexane and in mixtures of propane plus 5, 10, and 15 wt% hexane, hexene, methanol, ethanol, n-propanol and n-butanol. Hexane and hexene, which densify the propane, have no effect on the pressure-temperature location of the copolymer-propane cloud-point curve; however, the alcohols, which hydrogen bond to the acrylate repeat units, lower the curve by as much as 75-degrees-C. The magnitude of the temperature shift of the cloud-point curve decreases with increasing alcohol content as the acrylate units become saturated and the alcohol preferentially self-associates. Methanol is the least effective cosolvent as it self-associates more than the other alcohols at a given temperature.