Arkhipova V. The getting a modified calcium carbonate for plastic materials

The dissertation is devoted to the development of scientific bases of technology for obtaining urea-formaldehyde polymers modified by chemically precipitated calcium carbonate used for polymeric materials.The basic laws of the precipitation of the calcium carbonate with sodium carbonate and formation of urea-formaldehyde polymers in calcium chloride solution were theoretically and experimentally studied. The conditions for their joint precipitation, providing the greatest degree of transformation of the initial reagents were defined. It is established that the precipitation of calcium carbonate in the presence of nuclei of crystallization increases the degree of transformation. For crystal nucleation the method of calcium carbonate precipitation by the products of urea hydrolysis was used. Kinetic parameters of the reaction of calcium carbonate precipitation by products of urea hydrolysis and the process of carbamide-polymers polycondensation in the presence of calcium ions were determined. It is found that the rate of carbamide-polymers forming is affected by the concentration of calcium ions in the solution. The properties of powders modified by the calcium carbonate (the dispersion, the phase composition) for various conditions of deposition were fоund. On the basis of the data the technological parameters of obtaining modified calcium carbonate were substantiated. The resulting product was used as a filler of elastomeric material (rubber) and polyethylene of high and low pressure. It is shown that the using of calcium carbonate modified by urea-formaldehyde polymers improves the technological characteristics of filled materials compared with using unmodified calcium carbonate. The process chart to obtain calcium carbonate modified by urea-formaldehyde resins was developed.