boric acid

The kinetics granules of boric acid (GBA) dissolution were investigated based on the solution temperature and stirring frequency. Experimental mass transfer coefficients were determined and compared with theoretical values. The results indicate that increasing the stirring frequency and the solvent temperature increases the mass transfer coefficient. A computational relationship was derived, enabling the prediction of GBA dissolution based on solution temperature and stirring frequency.

The basic problems of development of restoration materials in Europe are considered. The basic ways of optimizing the binder compositions based on roman cement and hydraulic lime are presented and the technological parameters of formation of roman cement and hydraulic lime with marl and marlaceous limestone of Galicia are determined. The possibility of the use of additives- retarders of hydration of modified binders is showed and their influence on physical and mechanical properties of the studied compositions is established.

By using hydroxypropyl derivatives of urea esterified with boric acid as polyol components and 4,4’-diphenylmethane diisocyanate the rigid polyurethane foams have been obtained. The influence of boron and nitrogen atoms on the properties of foams, inter alia compressive strength and flammability, has been discussed. The presence of borate groups enhances the compressive strength of polyurethane foams meaningfully. However, the flammability of foams is determined by the participation of carbamide groups mainly.

The conditions of polyurethane foams preparation with the use of new boroorganic compounds as polyols have been presented. The new polyols have been obtained by two methods: in reactions of N,N’-bis(2-hydroxyethyl)oxamide (BHEOD) and boric acid (BA) with excess of ethylene carbonate (EC) and in reactions of BHEOD esterified with BA with excess of EC. The results of determination of foaming process parameters as well as of investigation of the foams properties have been given.