Electrokinetic, dielectric and electrorhelogical properties of boric acid doped chitosan/organo-perlite biocomposites

In this study, electrokinetic and electrorheological (ER) properties of environmentally friendly new functional polymeric materials were investigated. For this purpose, novel boric acid doped chitosan (CS-BA)/organo expanded perlite (O-EP) biocomposites were synthesized with two different CS ratios (C1: 10% and C2: 20%) by adding CS-BA solution into the O-EP dispersion, which was prepared in the presence of cationic surfactant (CTAB) medium. The characterizations of the biocomposites were carried out by various techniques. Electrokinetic properties of C1 and C2 particles were determined by following zeta (ζ)-potentials as a function of pH, electrolytic salts, surfactants, and temperature. The O-EP suspension showed negative ζ-potential in the pH = 3–11 range due to the presence of –OH groups. The ζ-potentials of the C1 and C2 particles shifted to the positive region at low pH values, thanks to –NH ₂ groups in the CS structure. Additionally, the ζ-potential values indicated that the biocomposite structures showed high colloidal stabilities (+30 mV≤ζ≤-30mV). Moreover, suspensions of C1 and C2 particles were prepared in silicone oil (SO) and subjected to the ER tests under various external electric field (E) strengths. It was concluded that novel C1/SO and C2/SO ER systems showed Bingham-like non-Newtonian fluid behaviors having electroactive vibration damping capabilities.