Gellan gum–graft–polyaniline—An electrical conducting biopolymer

• Published in: International journal of biological macromolecules Vol. 82; pp. 61 - 67
• Main Authors: Karthika, J.S., Vishalakshi, B., Naik, Jagadish
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-01-2016
• Subjects: AC conductivity; Aniline Compounds - chemistry; Biopolymers - chemistry; DC conductivity; Dielectric properties; Electric Conductivity; Gellan gum; Magnetic Resonance Spectroscopy; Microwave irradiation; Microwaves; Polyaniline; Polysaccharides, Bacterial - chemistry; Spectroscopy, Fourier Transform Infrared; Thermogravimetry; DC conductivity; Gellan gum; Microwave irradiation; Polyaniline; Dielectric properties; AC conductivity
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2015.10.061

•Electrical conducting gellan gum–graft–polyaniline were synthesized.•Grafted copolymers were characterized by FTIR, 1H NMR, TGA, UV/vis and SEM analysis.•GG-g-PANI shows threefold increase in DC conductivity as compared to GG.
Grafting of polyaniline (PANI) on to gellan gum (GG) was carried out in the presence of catalytic amount of ammonium peroxydisulfate (APS) as oxidant/initiator under mild acidic conditions by microwave irradiation technique. The grafting condition was optimized by varying the microwave power, exposure time and the composition of the reaction mixture. The graft copolymer GG-g-PANI was characterized by FTIR, TGA, UV/vis, 1H NMR and SEM techniques. The characteristic peaks at 1506, 1462, 1070 and 830cm−1 in the IR spectrum and signals at 7.3, 7.2, 7.1 and 4.0 δ in the 1H NMR spectrum confirms the grafting process. The TGA data reveals GG-g-PANI to be thermally less stable than GG. The optimum grafting was observed when the reaction mixture containing 0.066mmol APS, 0.1M aniline, 1M hydrochloric acid and 0.1g/dL GG was exposed to 80W microwave power for 40s. The DC and AC conductivity of the GG-g-PANI were measured using the ‘Two-point probe’ method based on which the dielectric properties were evaluated. GG-g-PANI exhibited appreciable electrical conductivity, which increased with the extent of grafting. The results indicate threefold increase in DC conductivity of graft copolymer as compared to GG.