Copolymerization of 4-chlorophenyl acrylate with methyl acrylate: Synthesis, characterization, reactivity ratios, and their applications in the leather industry

4-Chlorophenyl acrylate (CPA) was prepared by reacting 4-chlorophenol and acryloyl chloride in the presence of triethylamine in ethyl acetate solution. Poly(4-chlorophenyl acrylate) and copoly(4-chlorophenyl acrylate-methyl acrylate) were synthesized by the free radical polymerization in ethyl acetate at 70 degrees C. All the polymers were characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopic techniques. The composition of the copolymers was determined by the H-1-NMR spectroscopic technique, that is, by integrating the aromatic peaks corresponding to the 4-chlorophenyl acrylate unit against the carbomethoxy group in the methyl acrylate unit. The reactivity ratios were calculated by Fineman-Ross, Kelen-Tudos (K-T), and the extended Kelen-Tudos methods. The values of r(1) and r(2) obtained by these methods were in close agreement with each other; that is, r(1)(CPA) = 0.64 and r(2)(MA) = 0.13 by the K-T method. The number-average molecular weight ((M) over bar(n) = 1.55 x 10(3)), the weight-average molecular weight ((M) over bar(n) = 8.39 x 10(3)), and the polydispersity index ((M) over bar(w)/(M) over bar(n) = 5.42) of poly(CPA) were determined by gel permeation chromatography (GPC). Thermal properties of the polymers were studied in a nitrogen atmosphere using thermogravimetric analysis (TGA). As the CPA increases in the copolymer, thermal stability of the copolymer increases (e.g., 90% weight loss occurs at 480 degrees C for 20 mol % CPA, whereas the same weight loss occurs at 571 degrees C for 80 mol % CPA). Acrylic binders, based on the CPA-MA-BA terpolymer, of different glass transition temperatures were prepared for applications in leather industry as top coat and base coat materials. These acrylic emulsions were cast into thin films, and their characteristics were tested for physical properties. These acrylic emulsions were applied as a base coat on leather, and the compositions having T-g values of 1.08 and 9.25 degrees C were found to have excellent properties as base coats for leather when compared with commercial samples. (C) 1999 John Wiley & Sons, Inc.