Elaboration, synthesis and characterisation by conductometric study of chitosan materials in water

Abstract

Biopolymers are common ingredients in medical, technological, and industrial products. This paper presents the experimental analysis of conductometric properties of polysaccharides of chitosan (CH) in solutions in water W. The electrical conductivity was measured under the influence of increasing concentration of (0.5 to 10) g/l and increasing temperature of (288.15 to 318.15) K. The reduced electrical conductivity and the activation energy of reduced electrical conductivity Eσ are calculated. Biopolymer solutions exhibit a critical recovery of intrinsic electrical conductivity σ∗ and a critical concentration c*, separating solutions into dilute solutions and semi-dilute solutions. The dependencies of the activation energy with solution concentration and intrinsic electrical conductivity are discussed. The polysaccharide CH behaviour can be extrapolated from the Flory-Huggins theory by decomposing such as Eσ= Eσd+ Eσsd= EσS+ EσH. Where the EσS= Eσd is the entropy-originated term that reflects the tendency of molecules to adopt as many configurations as possible on the network and the EσH= Eσsd is associated with the energy variation that occurs when two molecules of different species are brought into contact. This enthalpy contribution represents well the non-Arrhenius behaviour. Principles that aid one to understand and interpret such results are discussed.