Resumo

ZUNIGA-RODRIGUEZ, Tarwin Duván; PENA-LARA, Diego  e  DIOSA-ATAIZA, Jesús Evelio. Phase behavior of nanostruturated membranes based on PVA, CS, H3PO₂ and Nb₂O₅. Rev.EIA.Esc.Ing.Antioq [online]. 2020, vol.17, n.34, pp.212-218.  Epub 15-Set-2021. ISSN 1794-1237.  https://doi.org/10.24050/reia.v17i34.1368.

Thermal behavior (phase equilibria) of nanostructured membranes based on poly(vinyl alcohol) (PVA), chitosan (CS), hypophosphorous acid (H3PO2), nanoporous micro-particles of niobium oxide (Nb2O5) using Differential Scanning Calorimetric (DSC) and Thermogravimetry Analysis (TGA) techniques were studied. Membranes PVA-CS 80:20+40%H3PO2+xNb2O5 with between x=0.02 and x=0.10 were prepared. For the DSC thermograms, the glass transition of PVA/CS 80:20 was observed at Tg ~26°C, for PVA/CS 80:20+40%H3PO2 at 95°C, and for those doped with Nb2O5 at 110°C. The melting point of PVA y PVA/CS 80:20 membranes was around 210°C, for PVA/CS 80:20+40%H3PO2 is no clearly observed, indicating the dominance of their amorphous phase. For doped with Nb2O5, the melting of their crystalline phases was around 180°C. Above 430°C, all membranes break down. The TGA thermograms for all membranes showed a continuous weight loss as the temperature increased to 200°C, this loss is due to the absorbed water molecules at the membrane's surface or caught inside of the polymer chains. Above 200°C, the membranes loss weight more quickly, being higher for the membranes without doping with Nb2O5, is observed.

Palavras-chave : Nanostructured membranes; PVA; Glass transition; TGA.

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