Starokadomsky D. Influence of high-disperced silicas on the photopolymerisation processes and properties of hardened composites

Subject of study: interactions silica-oligomer in photopolymer compositions. The aim of research is determinate the role of silicas of various dispersion and nature of surface in photopolimerisation processes of oligoetheracrylate compositions and mechanical properties of composites. Methods: IR- and ESR-spectroscopy, mass-spectrometry, calorymetry, dilatometry, X-ray analysis and standart methodics. It is shown that PP-characteristics (rate, conversion, lot of radicals) changes non-monotoneuosly as dependence on the silica concentration. Including of silica lead to falling of PP-rate while the conversion degree may increase. The filling by silicas A-100, A-175, A-300, A-450 do not change the frontal mechanism of PP, but brake the growing of polymer layer and initiate an inevenness of photohardening. It is established by ESR-method that silica stabilise the radicals and increase their concentration the more the higher his surface area. By IR-method the formation of hydrohenous bonds surface-olygomer was determined. It is established that index of crytical concentrations of silica in olygomer fall non-linearly with growing of his surface area. The strength characteristics are growing with decreasing of surface area. The optimal regimes of silica modification were found. On the base of experimental results as the litereture deta the new models and schemes were proposed.