Low and high temperature degradation of polymer/in situ silica hybrid nanocomposites

• Published in: Plastics, rubber & composites Vol. 35; no. 5; pp. 210 - 218
• Main Authors: Bandyopadhyay, A., Bhowmick, A. K.
• Format: Journal Article
• Language: English
• Published: London, England Taylor & Francis 01.06.2006; SAGE Publications; Maney
• Subjects: AGING; Applied sciences; Composites; Exact sciences and technology; Forms of application and semi-finished materials; NANOCOMPOSITES; Polymer industry, paints, wood; Technology of polymers; THERMOGRAVIMETRIC ANALYSIS; AGING; NANOCOMPOSITES; THERMOGRAVIMETRIC ANALYSIS; Thermogravimetric analysis; Thermal ageing; Acrylic elastomer; Hybrid material; Thermooxidative degradation; Temperature effect; Experimental study; Property processing relationship; Silica; Composite material; Thermal stability; Thermal properties; Polyvinylalcohol; Nanocomposites; Sol gel process; Concentration effect; Aging; Nanocomposite; Epoxidized natural rubber; Thermal degradation
• ISSN: 1465-8011; 1743-2898
• DOI: 10.1179/174328906X128180

Low and high temperature degradation behaviour of sol-gel derived polymer/silica hybrid nanocomposites were studied with the help of air aging and thermogravimetry. Acrylic rubber (ACM)/silica and epoxidised natural rubber (ENR)/silica nanocomposites at 30 wt-% tetraethoxysilane (TEOS) concentration showed more deterioration in strength on aging at 50, 70 and 90°C, compared with that of poly(vinyl alcohol) (PVA)/silica nanocomposite with similar TEOS concentration, although in all the cases, the control samples had shown more deterioration than the respective nanocomposites. Within rubber/silica system, ENR/silica was more resistant in lowering its strength compared with ACM/silica nanocomposite, which was ascribed to higher gel formation through greater interaction of silica with the polar carbonyl groups in the former on aging than in the latter system. Degradation behaviour at higher temperature, analysed by thremogravimetry under nitrogen displayed some weight loss ∼100°C with increasing TEOS concentration (10, 30 and 50 wt-% with respect to the polymer) owing to elimination of the byproducts of sol-gel reaction and the entrapped water. In rubber/silica system, the main degradation behaviour of the control sample did not change much on addition of TEOS (and increasing its concentration) whereas significant changes were observed in PVA/silica system. It was possibly due to PVA-silica bond formation, which decreased the crystallinity in PVA, as demonstrated by the differential scanning calorimetry. All the polymer/silica hybrid nanocomposites showed higher thermal stability on gradually increasing the TEOS concentration as the derivative thermogravimetric plots displayed lowering of degradation peak maxima.