Synthesis and Study of the Properties for Conductive Polyaniline/Polyurethane Film

Lim, Xiao Wei (2021) Synthesis and Study of the Properties for Conductive Polyaniline/Polyurethane Film. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

In this study, a multifunctional conductive blend based on thermoplastic polyurethane and polyaniline have been synthesized. Polyurethane/polyaniline (PU/PAni) film were prepared via chemical ex-situ polymerization process. The thermal stability, electrical conductivity and surface morphology properties were investigated. The structural characterization, chemical structure and oxidation states of the polymer films were confirmed by Fourier transform infrared (FTIR) and ultraviolet-visible spectroscopy (UV-VIS) respectively. UV-VIS spectra proved that pure PAni were in its conductive emeraldine salt state by showing three main characteristic peaks at 347nm which is the π to π* electron transition, 433nm corresponding to the polaronic transition from polaron→π* and 795nm attributes to formation of localized polarons. PU/PAni was proved to be low in electrical conductivity due to no appearance of polaron to π* peak. In the thermal stability analysis, the initial decomposition showed a decreasing trend from 246.86oC to 272.57oC as PAni content increases from 10 to 50% in PU/PAni due to the degradation of PAni and PU hard segments, whereas the second decomposition also showed a decreasing trend as PAni content increases from 10 to 50% in PU/PAni from 354.25oC to 435.16oC to due to degradation of soft segments of PU composed of polyols. It confirmed that there is less interaction between PU and PAni formation of urea linkages in PU/PAni due to insufficient hydrogen bonding between PAni in PU matrix. Based on the differential scanning calorimetry (DSC), the glass transition temperature (Tg) of PU/PAni decreases from -36.90oC to -40.48oC as PAni content increases from 10 to 50% due to absence of crosslinking between PAni and PU molecules. Besides that, the electrical conductivity of PU/PAni increases as from 0.3622 x 10-6 S/cm to 2.398 x 10-6 S/cm as PAni content increases. Moreover, the surface morphology of PU/PAni film were inspected by mini-scanning electron microscopy (SEM). From the SEM analysis, it is confirmed that PU/PAni was not successfully synthesized due to low compatibility of PU and PAni as PU was also not synthesized successfully.