Effect of boric acid pretreatment on the formation and structural evolution of polyvinyl alcohol -iodine complex

Boric acid pretreating Polyvinyl alcohol (PVA) polarizer films was prepared by pretreating PVA films with boric acid solutions with different concentrations, and then dyeing and stretching films after treatment. The effects of different concentrations of boric acid solution pretreatment on the formation and structure evolution of PVA-I 2 complex were studied. With the increase of boric acid solution concentration, FTIR showed that the hydroxyl stretching vibration peak of the film moves to higher wave number, indicating that the hydrogen bond between PVA molecular chains was weakened and the molecular chain was more prone to relative slip. DSC showed that the tensile induced crystallization of the film was inhibited and the crystallization was imperfect. Thus, the crystallinity and melting point decreased. One-dimensional XRD shows that PVA wafer spacing increases. Two-dimensional XRD shows that the orientation of the film increases at the same tensile ratio. Raman and UV spectra showed that the pretreatment of boric acid solution was beneficial to the formation of PVA-I 5 complex and the increase of orientation complex content, which improved the polarizing property of the film.