Thermally stimulated current and differential scanning calorimetry spectroscopy for the study of polymer nanocomposites

• Published in: Journal of thermal analysis and calorimetry 2010-07, Vol.101 (1), p.315-321
• Main Authors: Gaur, Mulayam Singh, Rathore, Bhupendra Singh, Singh, Pramod Kumar, Indolia, Ajaypal, Awasthi, Anand Mohan, Bhardwaj, Suresh
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Applied sciences; Calorimetry; Chemistry; Chemistry and Materials Science; Composites; Differential scanning calorimetry; Exact sciences and technology; Fillers; Forms of application and semi-finished materials; Inorganic Chemistry; Measurement Science and Instrumentation; Microcomputers; Nanocomposites; Nanomaterials; Nanostructure; Nanotechnology; Physical Chemistry; Polycarbonates; Polymer industry; Polymer industry, paints, wood; Polymer Sciences; Polymers; Spectroscopy; Spectrum analysis; Technology of polymers; Zinc oxide
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-010-0675-2

The thermally stimulated discharge current (TSC) and differential scanning calorimetry (DSC) spectroscopy have been recorded in 25 μm thick samples of pristine polycarbonate (PC) and zinc oxide nano particle-filled polycarbonate. Polycarbonate (PC)/zinc oxide (ZnO) nanocomposites of different mass ratio (e.g., 1, 3, and 5%) were prepared by sol–gel method, followed by film casting. The glass transition temperature of nanocomposite samples increases with increase in concentration of ZnO nano fillers. It is due to the strong interaction between inorganic and organic components. The TSC peaks of nanocomposite and pristine PC indicate the multiple relaxation process. It has been observed that the magnitude of TSC decreases with increase in concentration of nanofillers. The TSC characteristics of 5% filled nanocomposites shows exponential increase of current at higher temperature region. This increase in current is caused by formation of charge-transfer complex between inorganic phase (e.g., ZnO) and organic phase (e.g., PC). Thus, the nano material like zinc oxide transfers the charge carriers from inorganic phase to organic phase rapidly and resultant current increases exponentially. This current is known as leakage current or breakdown current. TSC peak height is observed as a function of the polarizing field. The height of TSC peak increases as the field increases in pristine PC, while TSC peak height is suppressed in nanocomposite samples. This indicates the amount of space charge is smaller in the nanocomposites with a proper addition of ZnO nano fillers than in the pristine PC.