Research Into Kinetic Patterns of Chemical Metallization of Powder­like Polyvinylchloride

We present kinetic patterns of metallization of zinc-activated polyvinylchloride in the solution of chemical copper plating. The influence was studied of pH of the medium and the amount of metal of the activator on the copper deposition rate on the activated polymeric surface. It was established that in the case of activation of the polymeric surface with zinc, the solution undergoes two competing reactions of copper reduction. By using a volumetric method, we determined that pH of the medium exerts a decisive impact on the reduction mechanism of copper. It is proved that with the growth of pH in the solutions of chemical copper plating and the amount of metal-activator, the amount of copper reduced as a result of exchange reaction with zinc increases. The optimal pH of the solutions for the course of reaction of copper reduction by formaldehyde is 12. The obtained samples of metallized powder-like polyvinylchloride contain a significant quantity of copper on the surface and could be used to create metal-filled composites.The research conducted allows us to establish optimal conditions and effectively influence the copper reduction process on the activated polymeric surface in the solutions of chemical metallization. By changing the speed and efficiency of copper deposition on the polymeric surface, it is possible to control the content of metal in polymeric composites that are obtained from such materials, and thus control their propertie

Technological Features in Obtaining Highly Effective Hydrogel Dressings for Medical Purposes

The new technology of formation of hydrogel dressings for medical purposes, containing particles of silver was developed. To obtain metal-containing composite hydrogels, we proposed a high-tech single-stage method, which involves polymerization of polymer-monomer compositions based on polyvinyl-pyrrolidone and 2-hydroxyethylmethacrylate with simultaneous chemical reduction of silver ions from its nitrate by ethanol. It was found by the thermometric research that the temperature conditions needed for chemical reduction of silver ions are achieved due to the heat, which is released at the exothermic polymerization reaction. The temporal and temperature parameters of polymerization depending on the composition of the original polymer-monomer composition, the content of solvent and of the initiator, and silver nitrate concentration were determined. They include the initial temperature of polymerization, maximum exothermic temperature, the time of reaching the maximum exothermic temperature, and duration of effect gel. The use of combined initiating system of iron (II) sulfate + benzoyl peroxide makes it possible to implement the process of obtaining hydrogels, containing silver particles, at room temperature, in the open air. The synthesis is technologically simple and is executed without complicated apparatus design. The authors proposed a new technology of formation of hydrogel films with the use of the centrifugal method. Polymerization with silver deposition occurs in the centrifugal form simultaneously with film formation, which allows obtaining the materials with predictable properties that have a uniform distribution of the filler with equal thickness and high quality surfaces in the polymer matrix. The film products obtained as a result of the developed technology can swell in water and other polar solvents, are characterized by durability, elasticity, bactericidal and antifungal properties. The results of the clinical studies showed sufficient clinical effectiveness of using the developed hydrogel dressings for medical purposes based on hydrogels, containing silver particles. Such materials in combination with the integrated therapy help to increase the speed and intensity of treatment of trophic venous ulcers of lower limb