A thermal degradation mechanism of polyvinyl alcohol/silica nanocomposites

• Published in: Polymer degradation and stability Vol. 92; no. 6; pp. 1061 - 1071
• Main Authors: Peng, Zheng, Kong, Ling Xue
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2007; Elsevier Science
• Subjects: Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; Nanocomposite; Polymer industry, paints, wood; Polyvinyl alcohol; Silica; Technology of polymers; Thermal degradation; Polyvinyl alcohol; Nanocomposite; Silica; Thermal degradation; Reaction order; Dispersion reinforced material; Experimental study; Composite material; Thermal stability; Thermal properties; Polyvinylalcohol; Reaction mechanism; Activation energy
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2007.02.012

The thermal degradation mechanism of a novel polyvinyl alcohol/silica (PVA/SiO 2) nanocomposite prepared with self-assembly and solution-compounding techniques is presented. Due to the presence of SiO 2 nanoparticles, the thermal degradation of the nanocomposite, compared to that of pure PVA, occurs at higher temperatures, requires more reaction activation energy ( E), and possesses higher reaction order ( n). The PVA/SiO 2 nanocomposite, similar to the pure PVA, thermally degrades as a two-step-degradation in the temperature ranges of 300–450 °C and 450–550 °C, respectively. However, the introduction of SiO 2 nanoparticles leads to a remarkable change in the degradation mechanism. The degradation products identified by Fourier transform infrared/thermogravimetric analysis (FTIR/TGA) and pyrolysis-gas chromatography/mass spectrometric analysis (Py-GC/MS) suggests that the first degradation step of the nanocomposite mainly involves the elimination reactions of H 2O and residual acetate groups as well as quite a few chain-scission reactions. The second degradation step is dominated by chain-scission reactions and cyclization reactions, and continual elimination of residual acetate groups is also found in this step.