Preparation and characterization of polypyrrole-layered silicate nanocomposites

Abstract

Polypyrrole (PPy) was synthesized in the presence of octadecylammonium montmorillonite (OC-MMT) 1-9 wt% using ferric chloride as an initiator. XRD results revealed that among these compositions, intercalated nanocomposites of OC-MMT and PPy generated with a significant amount of expanded Na-MMT remaining in the mixture. TGA results showed that the PPy had much improved in thermal resistance with a higher degradation temperature and lower weight loss compared to pure PPy. By FTIR, it was revealed that the materials prepared were intercalated nanocomposites with both OC-MMT and unmodified Na-MMT. After doping PPyC3 with DBSA, XRD patterns showed that eh doped one was the nanocomposites containing intercalated OC-MMT and exfoliated Na-MMT. It has better thermal resistance than undoped ones. The conductivity of the nanocomposites in ambient condition increased with OC-MMT content. Doping is less efficient to enhance conductivity in the presence of CO-MMT. Resistance and response time to CO2, CH4 and C2H4 increased with sample thickness. PPyC9 and DPPyC3 showed the lowest resistance to CO2 and only PPyC9 to C2H4 while all samples except nDPPyC3 showed the lowest resistance to CH4. From cross sensitivity, it was found that these samples are good sensors but not selective for these gases.