Properties of poly(vinyl alcohol)–borax gel doped with neodymium and praseodymium

Abstract

Neodymium and praseodymium ions, singly and in combination, have been doped into a poly(vinyl alcohol)-borax matrix. X-ray diffraction shows structural correlations from 2 to 6 Å and 15 Å, while small angle neutron scattering indicates that the rare-earth ions do not affect the nanoscale structures of the gels. Differential scanning calorimetry shows the glass transition temperature to increase with concentration of Pr in the gel. Excitation in the ultraviolet region leads to luminescent emission in the visible region. Simultaneous absorption in the visible region then leads to luminescent emission in the near infra-red region. The spectral qualities of the emission bands can be varied by choosing appropriate relative ratios of rare-earth species.

Solid-Phase Photocatalytic Degradation of Polyvinyl Borate

“…Figure 1 illustrates the FTIR spectra of pure PVA and PVB/TiO 2 composite, including 10 wt.% of the photocatalyst nanoparticles. The broad absorption band around 3200 cm −1 was related to the O-H group of polyvinyl alcohol, which formed complexes with boron-containing oxyanions during the crosslinking reactions [13]. On the other hand, this broad band could also be related to the stretching band of O-H, which might be due to unreacted O-H groups of polyvinyl alcohol ( Figure 1a) [14].…”

“…In addition, polyvinyl alcohol is a water-soluble polymer and crosslinking the polymer with boric acid enhances the moisture resistance of the matrix [12]. A few studies have been performed on crosslinking of polyvinyl alcohol with boric [4,[12][13][14]. In contrast to polyvinyl alcohol, PVB is a non-environmental polymer and it degradation is also significant in terms of human health and the environment.…”