X-Ray Studies on the Reaction Between Polyvinyl Alcohol and Congo Red

Physical Chemistry of Dyeing: State of Dye in Dyebath and in Substrate

“…199 Results of IR-spectroscopic measurements also reveal inter-molecular bonding between hydroxyl groups in disperse dye molecules and functional groups in certain polymers. 202 Interaction between dyes and hydroxylated polymers in solution has been detected by Centola,203 who suggested coordination complexes between dye and polymer through hydrogen bonding. 173 The viscosity of aqueous solutions of polyvinyl alcohol increases on addition of CI Direct Red 28 201 and also the X-ray diagram of polymer is remarkably altered in presence of this dye, indicating interaction between the dye and the polymer.…”

The effect of syndiotacticity on the gelation of aqueous poly(vinyl alcohol) solutions with Congo red

“…1 Investigations on the structure and properties of the gel were started in 1954 by Hirai, who attributed the elasticity of the gel to the entropic effect of PVA molecular segments, 2 and followed by Motoyama and Okamura, who discovered the specific effect of the Congo red with PVA and the polyelectrotic property of the PVA–Congo red complex. 3 The rigidity and melting of the gel, 4 the X‐ray pattern of the dried gel,5 the relaxation of applied force of the gel, 6 and the gelation process have been investigated since. Recently, the gelation ability was found not to increase monotonously with increasing Congo red concentration, but at a lower concentration, gel obtained was easier and crosslinks due to the complexation of the amino groups in the dye molecules were proposed to be influenced complicatedly by the Congo red concentration.…”