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English
Published
: 2022-09-18
Methods for studying radical polymerization. Part. II. The volumetric and spectrophotometric determination of the rate constant of thermal decomposition of azo initiators
Abstract
The relative degree (a) of thermal decomposition of initiators was defined as a measure of the process rate. This definition (eqn. 2) was introduced into the differential equation (1) of decomposition kinetics, which is of order x greater than or equal to 1 with respect to initiator, to simplify eqn. (7) that describes the decomposition rate and the rate constant. By eqn. (7), if the initiator decomposition rate is unrelated to nitiator's initial concentration, the reaction is first-order. he rate of decomposition can be followed in terms of any hysical parameter that varies with the instantaneous value of . Equation (7) incorporating the definition (2) was adjusted o the physical parameters characteristic of the volumetric ethod (measurement of nitrogen volume evolving on thermal ecomposition of azo initiators, eqns. 12-14 & 18) and of the pectrophotometric method (measurement of absorbance, eqns. 20- 22). Authors' studies were used to discuss the merits and demerits of these methods as applied to measure the thermal decomposition of AIBN and its derivatives in N,N-dimethylformamide (DMF) as solvent (Figs. 2-10). The volumetric results were affected neither by inhibitor nature nor by concentration; for systems containing both a monomer and an inhibitor, in addition to an initiator and solvent, the spectrophotometric method (UV-VIS) proved to be useless.
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Zasady cytowania
Szafko, J., Pabin-Szafko, B., Onderko, K., & Wiśniewska, E. (2022). Methods for studying radical polymerization. Part. II. The volumetric and spectrophotometric determination of the rate constant of thermal decomposition of azo initiators. Polimery, 47(1), 22-29. Retrieved from https://ichp.vot.pl/index.php/p/article/view/1939
