ARTICLE Sepiolite grafted polypyrrole: Influence of degree of grafting on structural, thermal, and impedance properties of nanohybrid Asif Raza 1 | Mehwish Tahir 1 | Amara Nasir 1 | Tariq Yasin 1 | Muhammad Nadeem 2 1 Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan 2 Physics Division, Directorate of Science, Pakistan Institute of Nuclear Science and Technology (PINSTECH), Islamabad, Pakistan Correspondence Tariq Yasin, Pakistan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad, 45650, Pakistan. Email: yasintariq@yahoo.com Abstract Conductive pyrrole monomer was grafted on vinyl modified sepiolite by sur- face initiated emulsion graft polymerization. Effect of process variables such as monomer, initiator, and surfactant on degree of grafting (%) were investigated. Maximum 745% degree of grafting was obtained at optimized grafting condi- tions. Structural changes in sepiolite by grafting of polypyrrole chains was con- firmed by Fourier transform infrared spectroscopy and X-ray diffraction techniques. Surface morphology of the grafted nanohybrid was investigated by scanning electron microscopy (SEM). Thermal studies were carried out to acquire information concerning thermal stability of the synthesized materials and it was found increasing with the increase in grafting (%) of polypyrrole in sepiolite grafted polypyrrole (MS-g-PPy). Complex impedance spectroscopic analysis was carried out to study the effects of grafting of PPy on the ac electri- cal properties of synthesized nanohybrid composite at ambient temperature in the frequency range of 0.5–10 7 Hz. The value of electrical conductivity was affected by degree of grafting (%) and maximum value of 0.85 × 10 -4 S/cm was achieved. Both dielectric loss factor and permittivity increase with the decrease of frequency exhibiting strong interfacial polarization at low frequency. KEYWORDS conducting polymers, functionalization of polymers, grafting 1 | INTRODUCTION Intrinsically conducting polymers (ICP), such as poly- pyrrole (PPy), polyaniline, polyacetylene, and polythiophene having alternating single and double bonds in their structure have shown potential in com- mercial applications due to their flexible structure and inherent conductive characteristics. [1] Among ICP's, PPy has received approbation from researchers due to its simple synthesis route and unique properties such as high conductivity and dielectric properties, good environmental stability, and mechanical properties. [2,3] Its fragile structure and poor postsynthesis processabilities limits its industrial applicability. [4] Researchers have over- come this problem by developing different polypyrrole composites such as covalently grafted polypyrrole/ graphene nanocomposite, [5] graft polymerization of pyr- role on to thiophene functionalized polystyrene [6] and chitosan/polypyrrole/sepiolite conducting biohybrid nanocomposites. [7] PPy and its composites have been used in many applications, such as bio/chemical sensors, [8] energy storage device, [9] switchable membranes, [10] Received: 13 November 2019 Revised: 18 January 2020 Accepted: 27 January 2020 DOI: 10.1002/app.49085 J Appl Polym Sci. 2020;e49085. wileyonlinelibrary.com/journal/app © 2020 Wiley Periodicals, Inc. 1 of 11 https://doi.org/10.1002/app.49085