Study on the structure and processibility of the iodinated poly(vinyl alcohol). I. Thermal analyses of iodinated poly(vinyl alcohol) films

Abstract

ABSTRACT:To get more information on the structure of iodinated poly(vinyl alcohol) (PVA), thermal analyses of unoriented and oriented PVA films were conducted. Unoriented and oriented PVA films iodinated with aqueous solutions at selected concentrations were carried out by thermogravimetry (TG) and differential scanning calorimetry (DSC). The TG curves for the iodinated film shows four or five weight-loss zones associated with degradation and evaporation of excess I 2 molecules and I 2 molecules from I 5 Ϫ , partial OH side groups on PVA, and I 2 from I 3 Ϫ , the remaining OH groups and the partial main chains, the remaining main chains, and a very small amount of residue from PVA. The char of KI salts remained. By investigating the TG results, it was identified that the amount of I 3 Ϫ ions increased with increasing I 2 /KI up to 65%, but above that weight gain, the rate of increase diminished and the amount of I 5 Ϫ ions from the I 3 Ϫ ions increased. The TG curve for the oriented film was very similar to that for the unoriented film except for its greater weight loss at zone I due to narrow space in amorphous region. The DSC thermogram of iodinated films indicated two peaks at 145°C and 160 -170°C, corresponding to the melting of crystals and the degradations of OH groups and main chains, respectively. The maximum temperatures of peaks were much lower than that of the untreated one.

Synthesis and characterization of nano‐sized NiO and its surface catalytic effect on poly(vinyl alcohol)

“…The sharp band at 1089 cm −1 is responsible for the COC stretching of ester group present in the PVA backbone. The corresponding bending and wagging of CH 2 vibrations are observed at 1438 and 1378 cm −1 respectively, and CH wagging at 1247 cm −1 28, 29…”

Molecular iodine/polymer complexes

“…Shin et al [168][169][170][171] and Woo et al [172] embarked on the study of the structure and processability of iodina tion products of oriented and unoriented PVA using I 2 /KI solution at room temperature for 24 h. The crystallinity of oriented and unoriented PVA subjected to iodination was 21.3% and 37.0%, respectively. The weight gains and molar ratios of the unoriented and oriented films increased rapidly with I 2 /KI concentration to 1.0 mol/l and 0.5 mol/l, respectively.…”

Advancement in Microstructural, Optical, and Mechanical Properties of PVA (Mowiol 10-98) Doped by ZnO Nanoparticles

“…This change in crystallinity signifies the structural regularity occurring in the main chains of the polymeric molecules on doping. stretching vibration associated with PVA molecule [12,13]. It is observed that after the action of ZnO nanoparticles dispersing in the PVA matrix the FTIR spectra exhibit several irregular shifts related to corresponding bands with change in intensities of pure PVA as presented in Table 1.…”