Thermal Degradation Behavior of Polyvinyl Alcohol/Starch/Carboxymethyl Cellulose/ Clay Nanocomposites

Abstract

Polyvinyl alcohol (PVA) / starch (S) /Carboxy methyl cellulose (CMC) / Montmorillonite (MMT) bionanocomposite films were prepared from PVA, MMT, CMC and soluble starch aqueous suspensions by casting method in the presence of a plasticizer that contained glycerol. The kinetics of thermal degradation of PVA/S/CMC/MMT blends was investigated by thermogravimetry (TGA) and derivative thermogravimetry (DTG). Experiments under non-isothermal conditions were carried out for samples in nitrogen (the inert atmosphere in order to avoid thermoxidative degradation) at heating rates of 7.5, 10 and 150C/min. The Ozawa method was used to calculate the activation energy of thermal degradation for PVA/S/CMC and PVA/S/CMC/MMT blends. The thermal stability of PVA/S/CMC/MMT blends is higher than that of PVA/S/CMC suggesting that the addition of MMT improved the thermal stability of PVA/S/CMC blend. At least four degradation distinct stages were identified in the PVA/S/CMC/MMT blends by means of using TGA, being assigned to the mass loss due to the plasticizer leaching, and to the degradation of the starch, CMC and PVA fractions.

Physicochemical properties and AC magnetic field induced heating properties of solvothermally prepared thiospinel: Fe3S4 (greigite) nanoparticles

“…This was attributed to the removal of PVA from the surface of the MNPs [77]. The temperature range of ∼ 300 °C-450 °C, for the removal of PVA, was found to be in agreement with the typical PVA decomposition temperature ranges of ∼ 250 °C-500 °C, as reported by Yang et al [78], ∼ 200 °C-500 °C, as reported by Taghizadeh and Sabouri [79], and ∼ 300 °C-500 °C, as reported by Peng and Kong [80]. Earlier studies indicated that PVA decomposition occurs in two steps, where the first step involves depolymerisation and dehydration, followed by intramolecular cyclization in the second step [81].…”

Blend of polyvinylpyrrolidone/thermally reduced graphene for adsorption of heavy metal ions in water

“…The Raman spectra of graphite, GO and graphene are shown in figure 1. The spectrum of graphite exhibits two high and sharp G and 2D peaks at about 1,580 and 2,700 cm −1 , respectively, and a small D peak at about 1,350 cm −1 for a fraction of the defects found in graphite [32]. The spectrum of GO shows a significant increase in the intensity of the D peak and a decrease in the intensity of the G and 2D peaks, indicating a high degree of oxidation and an increase in the number of defects [33].…”

Synthesis and characterization of conjugated PVA/PANi blend doped with functionalized Graphene for Thermoelectric Applications

“…With increasing the temperature gradually, the adsorbed water (including the chemisorbed or physically absorbed water molecules) is released, and the weight loss percentages varied ≈ from 7.3% and 0.4% for the 0 wt.%, 25 wt.% FGNP films at T= 150 o C, respectively. The rapid weight losses that occur in the second and third regions (over 150-400 o C) can be attributed to the melting of the blend accompanied by some vapor loss, as well as the thermal degradation (first degradation process) of polymer blend intermolecular hydrogen bonding on the nanocomposite films [31]. The attributions of the decomposition of the blend with gases released like the carbon dioxide (CO2), melting, and partial thermal decomposition of FGNP dominate the fourth weight loss region exhibiting the lowest weight loss, about 17.3% for the 25 wt.% FGNP film [32].…”