Abstract
This study seeks to determine the effects of polymer structure and composition on the cloud-point of polymer-solvent mixtures. Mixtures of ethylene gas with poly(ethylene-co-methyl methacrylate), poly(ethylene-co-methacrylic acid) and poly(ethylene-co-methyl acrylate) copolymers were studied at high pressures and temperatures. In addition to polymer phase behavior, ethylene-monomer systems were studied at low pressures and temperatures. Ethylene-acrylic acid and ethylene-methyl acrylate mixtures were studied at low pressures and temperatures to determine bubble and dew points and to evaluate whether three phase regions exist in the systems. The apparatus used for high pressure phase study consists of a high-pressure phase cell, which allows for easy visual detection of phase transitions. The cell has a maximum operating pressure of 32500 psig and maximum operating temperature of 250'C. When the polymer-ethylene mixture separates into two phases, the system becomes dark; the pressure and temperature at which this occurs is referred to as the cloud-point. A series of cloud-point measurements were taken at various temperatures to produce phase boundary curves for a polymer. When the efhylene-monomer system separates into two or three phases liquid droplets or bubbles form. The bubble and dew points and three phase regions were determined to develop critical mixture curves and phase diagrams for each of the systems investigated.
Purifoy, Jonathan Patrick (1998). Phase behavior of polymers and monomers. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1998 -THESIS -P87.