Kinetics and mechanisms of early stages of resorcinol-formaldehyde polymerization : praca doktorska / Katarzyna Zofia Gaca. – Glasgow, 2012. – 349 s. : rys., tab. – University of Strathclyde. Dept. ... więcej

Kinetics and mechanisms of early stages of resorcinol-formaldehyde polymerization : praca doktorska / Katarzyna Zofia Gaca. – Glasgow, 2012. – 349 s. : rys., tab. – University of Strathclyde. Dept. of Chemical and Process Engineering. – Promotor: prof. Jan Sefcik. – Bibliogr. 125 poz., Abstr.

The DLS experiments proved that regardless of the R/C and R/W ratios, the growth of primary particles which subsequently form a solid network in the gel follows the same pattern. Moreover, the average ... więcej

The DLS experiments proved that regardless of the R/C and R/W ratios, the growth of primary particles which subsequently form a solid network in the gel follows the same pattern. Moreover, the average hydrodynamic radius of these particles is similar across all samples. It was found that the higher the temperature, the concentration of reactants or the catalyst, the sooner the particles reach their final radius. Analysis of autocorrelation functions development in time allowed to confirm the gelation times and to determine the intermediate stage between the sol and gel forms. These novel results disprove previous suggestions that the catalyst directly controls the size of particles forming the gel structure. Experiments on the reacting systems were completed by measurements of pH changes in the course of the reaction. As it turned out, regardless of the catalyst and reactants concentration, all reacting samples exhibited a pH drop of the same magnitude within the first 30-40 minutes. A number of theories explaining this phenomenon are formed in this work, however, none of them seems to be fully explain it.