Synthesis And Charaterization Of Silver Or Silver Sulfide Filled Poly (3-Hydroxybutyrate) Nanocomposite
Loading...
Date
2012-03
Authors
Yeo, Siew Yean
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Ag and Ag2S hydrosols were synthesized via chemical reduction and reflux methods respectively. A simple aqueous to organic phase transfer technique was employed to transfer the Ag and Ag2S nanoparticles from the respective hydrosol into poly(3-hydroxybutyrate) [PHB] chloroform solution. The Ag and Ag2S nanoparticles were stabilized by the PHB polymer in the organosols. The presence of metallic Ag or the Ag2S particles in the newly formed nano-biocomposites were confirmed by the X-ray Diffraction (XRD) technique. The particles size of Ag and Ag2S were within 7-12 nm and 14-24 nm respectively. At low concentration of PHB, the shape of Ag particles was sphere while for Ag2S particles were hexagonal-like. However, at high concentration of PHB, both types of particles were sphere-like. Thermal and non-isothermal degradation data of Ag/PHB and Ag2S/PHB nano-biocomposites were obtained via Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) respectively. Both nano-biocomposites showed similar thermal trend where a decrement in melting, glass transition and degradation temperatures with respect to neat PHB were observed. The DSC and TGA results show the depression of thermal parameters were dependent on Ag or Ag2S loading. Kinetic analysis of non-isothermal degradation of PHB and the nano-biocomposites were carried out and the kinetic parameters were calculated via Kissinger method. The values of thermal degradation activation energy (Ed) for Ag/PHB and Ag2S/PHB nano-biocomposites were less than neat PHB. The Ag and Ag2S nanoparticles likely catalyzed the thermal degradation of PHB in the nano-biocomposites. The slight increases in the Ed values with the increase in Ag or Ag2S content in the nano-biocomposites was attributed to the aggregation and agglomeration of nanoparticles during heating process.
Description
Keywords
Synthesis and characterization of silver , filled poly(3-hydroxybutyrate) nanocomposites