Influence of collagen modifications on qualitative parameters of thermoplastic adhesive mixtures and its microbiological stability

Influence of collagen modifications on qualitative parameters of thermoplastic adhesive mixtures and its microbiological stability.This work presents the possibility to use the modified biopolymer collagen for preparation of ecologic, biologically degradable thermoplastic adhesives. Collagen prepared from secondary raw materials of the leather and food industry was applied as a starting material for the preparation of thermoplastic, formaldehyde-free adhesives intended for use in woodworking, furniture and paper industries. Glued joint obtained high strength and flexibility after application of modification plasticisation agents based on collagen. Modifications of collagen glue with keratin biopolymer increased its resistance to water and the strength of the glued joint. Prepared samples of hot-melt adhesive had higher bonding strengths than standard commercial adhesives. The highest tensile strengths were achieved by applying of undiluted adhesive with the application of 2.5% keratin hydrolysate into hot-melt adhesive. As collagen is a natural polymer easy biodegradable in the aquatic environment, the research has focused on the possibility of its microbiological stabilization with aqueous solutions of ionic and colloidal silver. The highest microbiological activity was observed in a sample of ionic silver sulphate solution with a concentration of 2000 ppm Ag+. Its 1% concentration was applied for antibacterial thermoplastic stabilization of formaldehyde-free collagen glue.

Electrical Conductivity and Structural Studies on the Binary System BiI3-Ag2SO4

A new solid-state pseudo binary system BiI3_-Ag2SO4 involving bismuth triiodide (BiI3) and a silver oxysalt namely silver sulphate (Ag2SO4) has been prepared using rapid melt-quenching technique. AC conductivity studies have been carried out on the nine different samples of the (BiI3)x –- (Ag2SO4)(1-x) system with compositions corresponding to x=0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8 and 0.9 mole fraction at temperatures ranging from room temperature (298 K) to 433K. The bulk resistance values estimated using complex impedance plots indicated that electrical conductivity of the synthesized solid specimens would vary from 2.9 x10-2 to 3.4 x10-6Scm-1 thus suggesting the present system to be ionic in nature. The extent of ionic conduction due to Ag + cation has also been analyzed using Wagner’s dc polarization technique whereas detailed structural characteristics of the various compositions derived from Fourier transform infrared (FTIR) spectroscopy and features of surface morphology of these samples obtained using scanning electron microscopy (SEM) have further supported the ionic nature of the chosen system and suggested possible application as a solid electrolyte in electrochemical devices.