Department of Chemistry
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Item Development of Conducting Filler Based Nanocomposites for Enhanced EMI Shielding Applications(Library Information Services, COMSATS University Islamabad, Lahore Campus, 2021) Taskeen Zafar; SP23-R06-024; Dr. Imran Hassan; LHR TP 9463The increasing need for efficient, lightweight, and cost-effective electromagnetic interference (EMI) shielding materials has spurred significant research into polymer-based composites. This study presents the development of polyaniline-carbon fiber (PANI-CF) composites, enhanced with poly (3,4 ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), to achieve superior electrical conductivity and shielding performance. The composites were prepared via in-situ polymerization of aniline, incorporating varying concentrations of carbon fiber (2wt% ,5wt%), followed by PEDOT:PSS coating to improve conductivity. Characterization revealed significant improvements in structural, morphological, and functional properties of composites. Fourier transform infrared spectroscopy (FTIR) validated successful chemical interactions between the PANI matrix, CF, and PEDOT:PSS. X-ray diffraction (XRD) analysis confirmed the semi-crystalline structure of PANI and the graphitic nature of CF, with higher CF content enhancing crystallinity. Scanning electron microscopy (SEM) revealed uniform CF dispersion and the formation of smooth, continuous PEDOT:PSS coatings, mitigating filler agglomeration and enhancing electrical pathways. Thermogravimetric analysis (TGA) further highlighted the improved thermal stability, attributed to the dispersion of CF and PEDOT:PSS coating. Electrical measurements shows the shift from semiconducting to ohmic behavior in PANI CF composites, enhanced by filler content and PEDOT:PSS coating, improving charge transport and conductivity. Conductivity measurements demonstrated significant improvement, with the PANI-5%CF-PEDOT:PSS composite achieving the highest conductivity of ~0.012 S/cm. The optimized composites exhibited remarkable conducting properties making it an effective material for EMI shielding. These findings demonstrate the potential of PANI-CF-PEDOT:PSS composites as lightweight, corrosion-resistant, and thermally stable alternatives to conventional EMI shielding materials.Item Improvement in the Flame-Retardant and Mechanical Properties of Thermoplastic Polyurethane Nanocomposites(Library Information Services COMSATS University Islamabad Lahore Campus, 2020-02-19) Sidra Faryal; SP19-R06-027; Dr. Imran Hassan; LHR TP 6539Recently, nanocomposites of polymers gained much attention in materials as they frequently show advanced features as compared to their complement polymer micro-composites. In this study, Thermoplastic polyurethane (TPU) is used as matrix and Antimony trioxide (primary flame retardant) and Montmorillonite organo-clay (secondary flame retardant) along with Benzoflex (plasticizer) are used as fillers. Nanocomposites of varying composition (TPU-1 to TPU-6) are prepared via melt-mixing method. Samples are compressed to form sheets of desired dimensions through compression molding hydraulic press machine. Fourier transform infrared (FTIR) was applied for functional groups analysis. Scanning electron microscopy (SEM) was performed to examine the dispersion of fillers in the Nanocomposites. Differential scanning calorimetry (DCS) was also performed for evaluation of properties such as melting temperature and glass transition temperature. Tensile test was performed through Universal testing machine (UTM) which showed that Young’s Modulus mproved from 147.348 MPa for neat sample (TPU-1) to 244.568 MPa for TPU-6. UL-94 test was executed to observe flame retardance. Sample of interest (TPU-6) achieved V-0 classification in UL-94. All these results confirmed the synergistic effect of primary and secondary flame retardants. Optimum increase in flame performance and mechanical strength was observed for TPU-6.