Research Output
Chitosan/polyethylene oxide (Peo) filled carbonized wood fiber conductive composite film
The potential of chitosan-polygonum minus leaf mediated silver-nanoparticles composite as green conductive biofilm
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Publication
Biopolymer-based conductive polymer composites (CPCs) would open up various possibilities in biomedical applications owing to ease of processing, renewable resource and environmentally friendly. However, low mechanical properties are a major issue for their applications. In this study, the investigated the conductivity of chitosan/ PEO blend films filled with carbonized wood fiber (CWF) prepared by solution casting. The effect of CWF was also investigated on tensile properties and their morphological surfaces. The tensile results from different ratios of chitosan/PEO blend films without CWF show that the tensile strength and modulus increased with the increase of chitosan content and chitosan/PEO blend film with 70/30 ratio exhibited the best combination of tensile strength and flexibility. However, a reduction of tensile strength was observed when CWF amount was increased while the modulus of the tensile shows an increment. The film also exhibited higher electrical conductivity as compared to low chitosan ratio. The addition of CWF greatly enhanced the conductivity three-fold from 10-10 to 10-6 S/cm. The electrical conductivity continued to increase with the increase of CWF up to 30 wt%. The surface morphology by Scanning Electron Microscopy (SEM) exhibits the absence of phase separation for the blends indicating good miscibility between the PEO and chitosan. Incorporation of CWF into the blend films at 5 wt% showed agglomeration. However, the increase of CWF created larger agglomerations that formed conductive pathways resulting in improved conductivity. FTIR analysis suggested that intermolecular interactions occurred between chitosan and PEO while CWF interacts more with the protons of PEO.
Publication
Silver-nanoparticles (AgNPs) from leaf extract have gained considerable interest from years ago until recently. However, the potential of green-synthesised AgNPs as a conductive filler in polymer biocomposites has not been widely investigated. Herein, a series of biopolymer-silver nanoparticle films were prepared by dispersing the suspension of Polygonum minus leaf mediated AgNPs into chitosan (CS) matrix via solution casting. In this work, the physicochemical properties of the composite films were evaluated, and structural property was analysed by Fourier transform infrared (FTIR) spectroscopy. The electrical conductivity and surface morphology were investigated by two-point probe and scanning electron microscopy (SEM), respectively. From the evaluation of moisture uptake, solubility and degradation tests, the rate of moisture uptake reduced as AgNPs concentration increased whereas the solubility and degradation rate increased with increasing addition of AgNPs. The FTIR analysis confirmed that there was no new covalent bond formed and suggested that AgNPs interact non-covalently with amine and hydroxyl groups of chitosan matrix. The conductivity of the CS-AgNPs films increased with one-order magnitude from 10-8 to 10-7 S/cm compared to pristine CS film. The percolation threshold was achieved at 20 wt% of AgNPs and the highest conductivity was achieved at 30 wt% AgNPs with the conductivity value of 3.20 x 10-7 S/cm. SEM micrographs revealed that the composite film with 30 wt% AgNPs exhibited smooth and homogeneous surface which agrees well with the conductivity results. This CS-Polygonum minus leaf mediated AgNPs composite film shows potential as an alternative for biodegradable biomedical implants, smart packaging and wearable electronics applications.