COMPLEXATION BETWEEN POLYOXYETHYLENE AND POLYMETHACRYLIC ACID - THE IMPORTANCE OF THE MOLAR-MASS OF POLYOXYETHYLENE

The effect of the molar mass of polyoxyethylene, POE, upon the mechani sm of complexation with polymethacrylic acid, PMAA, has been examined, using pH, density, calorimetric and cloud point studies. Complexation has been found to occur, even for POE of molar mass as low as 200, fu rther, the mechanism appears to be more complex than a simple 1:1 base mole pairing of oxyethylene units (OE) with methacrylic acid units (M AA) by a hydrogen bond mechanism. When the molar mass of POE is < 2000 complexation arises between already pre-existing OE dimers and MAA vi a hydrogen bonding. For POE molar mass of 2000 and above, hydrophobic pairing of OE and MAA units occurs, followed by hydrogen bonding of an other OE or MAA, depending upon the relative concentrations of POE and PMAA.