Fabrication and Characterization of Biopolymer Nanocomposites From Natural Resource Materials M.T. Ramesan, K. Surya Department of Chemistry, University of Calicut, Calicut University P.O, Kerala 673 635, India In this study, nanocomposites of cashew tree gum (CTG) encapsulated nano-magnetite (Fe 3 O 4 ) was pre- pared and characterized by FTIR, UV–visible, X-ray dif- fraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), magnetic and con- ductivity measurements. The characteristic absorption peaks in FTIR and UV–vis spectra of CTG was found to be shifted to higher wave numbers in CTG/Fe 3 O 4 com- posite, which is due to the intermolecular interaction between nanoparticles and the CTG. The XRD patterns indicated that amorphous region of gum was decreased by the addition of metal oxide nanopar- ticles. SEM images show that nano-Fe 3 O 4 was uni- formly dispersed in the cashew gum segments. DSC analysis revealed that the glass transition temperature and melting behavior of composites were higher than those of the pure gum. TGA results indicated that the thermal decomposition temperature of the composite increases with the increase in concentration of metal oxide nanoparticles. The magnetic properties studied by a vibrating sample magnetometer indicate that electromagnetism of CTG/Fe 3 O 4 nanocomposites were superparamagnetic. The values of saturation of mag- netization (M s ) and remanence (M r ) increases, while the coercivity (Hc) decreased with increase in Fe 3 O 4 content in the composite. The AC electrical conductiv- ity of the nanocomposites was significantly increased with the increase in Fe 3 O 4 content in the nanocompo- site. Due to the ordered structure of polymer compos- ite, the dielectric constant and dielectric loss tangent (tan d) of nanocomposites were also increased with increase in the concentration of nanoparticles. POLYM. COMPOS., 00:000–000, 2016. VC 2016 Society of Plastics Engineers INTRODUCTION Fabrication of synthetic and natural polymers with var- ious composites have become one of the most important area of research in polymer engineering and science because of their low cost, easy availability, and they can be tuned to modify their properties for electro active behaviors. However, the increased production of synthetic polymer composite caused huge environmental pollution [1]. Hence biodegradable natural polymer is an alterna- tive, quick, and very effective way to reduce the plastic waste without polluting the environment. Recently, plant products are used as an alternative to synthetic product due to environmental friendliness, nontoxic, biocompati- bility, cheap, and easily available from agricultural resources [2–4]. Natural gums obtained from plants have wide spread of industrial application because to their abil- ity to form viscous solution, gel, or stabilize emulsion systems [5–7]. Cashew tree gum (CTG) is one of the major byproduct of cashew industry and demanding for industrial applications that has not yet properly been explored. In recent years, electrically active polymers are of great interest due to various applications such as elec- tronic shielding, sensors, and sensitive membranes [8, 9]. However the electro-active polymers have some limita- tions due to their toxicity, poor mechanical properties, and biocompatibility. Biopolymers composite have unique physical and mechanical properties making an environ- mental friendly biocompatible material through different process. Silica containing biopolymer composite is attrac- tive for the preparation of multifunctional material with different applications [10]. CTG is a water-soluble poly- mer with different composition of polysaccharide such as galactose, glucose, arabinose, and rhamose [11, 12]. How- ever, CTGs possess poor mechanical and thermal proper- ties with low electrical conductivity. The introduction of metal nanoparticles into this matrix can increases the mechanical, thermal, and electrical conductivity and sometimes creates special properties developed from the synergetic effect between the nanoparticle and the poly- mer matrix [13, 14]. Therefore, one of the ways to mod- ify the polymeric materials is to prepare polymer with fillers. But the properties of these composites depend upon the geometry of filler particles and the orientation of particles inside the macromolecular chain. Keeping this in mind, we modify the properties of CTG by the incor- poration of magnetite nanoparticles, to improve the mechanical, thermal, and electrical properties of gum and thus contribute to fabrication of environmental friendly Correspondence to: M.T. Ramesan; e-mail: mtramesan@uoc.ac.in DOI 10.1002/pc.23978 Published online in Wiley Online Library (wileyonlinelibrary.com). VC 2016 Society of Plastics Engineers POLYMER COMPOSITES—2016