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

The effect of different types and levels of plasticizers on the thermal and physical-mechanical properties of equilibrated methacrylic acid copolymers was studied. The efficiency of this plasticization was studied by determining the dependence of the copolymer's thermal and physical-mechanical properties on plasticizer concentration and molecular structure. Gas chromatography (GC) and headspace-gas chromatography techniques were used to specifically determine the levels of plasticizer and residual solvent, respectively, in the polymeric film, and to exclude any solvent-induced plasticization. The effect of plasticizer on the 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 solely be dependent on the aqueous solubility of the plasticizer, but also on the chemical structure of the plasticizers. Of the plasticizers investigated, triacetin (TRI) had the greatest effect on reducing the brittleness of the polymer, followed by triethyl citrate (TEC). This effect was related to their differences in molecular size and subsequent greater ability to interact with the polymer chains as compared to the other plasticizers investigated including acetyl triethyl citrate (ATEC), tributyl citrate (TBC), and acetyl tributyl citrate (ATBC).