Copolymer of Acrylonitrile/Acrylic Acid Film Dendrigrafted with Citric Acid: Host/Guest Properties of Dendrigraft/Dye Complexes in Relation to Acrylic Acid Content

Host/guest properties of acrylonitrile/acrylic acid copolymer (P(AN/AA)) film withvarious contents of acrylic acid (AA) were examined on dendrigraft/dyecomplexes in a divergent synthetic route. The reactions were performed onP(AN/AA) films containing 5, 10 and 20 mol% acrylic acid in feed. The products wereanalyzed using 1H NMR, FTIR, UV-visible spectroscopy, density determination,acidimetric titration, staining and transfer printing. The results showed that for the filmsbased on three different amounts of acrylic acid, the relatively higher acid contentshowed a lower rate of conversion due to the reduced steric hindrance. Furthermore,the dyes were used to probe the structure of dendrigraft on the P(AN/AA) film. Stainingwith methylene blue showed the interaction with the exterior end groups; while printingwith disperse dyes as guest molecules may illustrate the effectiveness of the hollowinterior spaces. In the trend of dye uptake and density versus generation numbers, theemerging maximum dye uptake and minimum density in the first generation confirmedthat a ''dense shell'' dendritic structure is being formed. Also, the effects of acrylic acidcontent and the steps number in dendrigraft structure are explained on the basis offilms characteristics with reference to the dendrigraft architecture.