Copolymer of Acrylonitrile/Acrylic Acid Solid Surface Dendrigrafted with Citric Acid-comparison between Film and Fiber

Abstract

The synthesis of a dendritic polymer of citric acid(CA) on a solid-phase of acrylonitrile /acrylic acid copolymer P(AN/AA) core from zero(G0) through fourth step (G4) is described. Copolymer of P(AN/AA) was synthesized by suspension polymerization. The product was analyzed by elemental analysis technique and nuclear magnetic resonance (1H NMR) that showed 15 % of the copolymer was acrylic acid. The solution of P(AN/AA) in dimethylformamide (DMF) was cast into film with 350 μm thickness. Also the solution of P(AN/AA) in DMF was converted in to fiber by a laboratory wet spinning machine. The diameter of the filaments was 200±20 μm, after drying. Dendritic molecules were grown by a reaction between the carboxylic acid of acrylic acid and hydroxyl group of citric acid activated by dicyclohexylcarbodiimide (DCC) on fibers and films samples. Products were analyzed using Fourier transform infrared spectroscopy (FTIR) in transmission mode and 1H NMR. The analysis of the results indicates the formation of carboxylic acid of citric acid on the P(AN/AA) films and fibers. The percent of conversion of the reaction of copolymer with citric acid was calculated from the results of the measurement with NMR. The percent of conversion shows a gradual reduction with the increase in step numbers. Also it shows that the percent of conversions of the reactions on the fibers are higher than on the films. Reduction of the conversion with the step number and the differences in the conversion for the fibers and films seem to be very interesting and it is explained based on the established theories and the pertinent literature.