INFLUENCE OF WATER-SOLUBLE AND INSOLUBLE PLASTICIZERS ON THE PHYSICALAND MECHANICAL-PROPERTIES OF ACRYLIC RESIN COPOLYMERS

The effect of different types and levels of plasticizers on the therma l and physical-mechanical properties of equilibrated methacrylic acid copolymers was studied. The efficiency of this plasticization was stud ied by determining the dependence of the copolymer's thermal and physi cal-mechanical properties on plasticizer concentration and molecular s tructure. Gas chromatography (GC) and headspace-gas chromatography tec hniques were used to specifically determine the levels of plasticizer and residual solvent, respectively, in the polymeric film, and to excl ude any solvent-induced plasticization. The effect of plasticizer on t he thermal properties showed a strong correlation with the mechanical behavior of the methacrylic acid copolymer. Results indicated that the ability to interact with the methacrylic acid copolymer may not solel y be dependent on the aqueous solubility of the plasticizer, but also on the chemical structure of the plasticizers. Of the plasticizers inv estigated, triacetin (TRI) had the greatest effect on reducing the bri ttleness of the polymer, followed by triethyl citrate (TEC). This effe ct was related to their differences in molecular size and subsequent g reater ability to interact with the polymer chains as compared to the other plasticizers investigated including acetyl triethyl citrate (ATE C), tributyl citrate (TBC), and acetyl tributyl citrate (ATBC).