Solubility of Irgacure® 2959 photoinitiator in supercritical carbon dioxide: Experimental determination and correlation

Abstract

CIBA photoinitiator Irgacure® 2959 is a highly efficient radical photoinitiator for UV curing systems. Furthermore, and due to its proven low cellular toxicity, this photoinitiator can also be employed in the photopolymerization of polymers and copolymers intended for biomedical and tissue engineering applications, not only in conventional pharmaceutically accepted liquid solvents, but also in supercritical CO 2 (scCO 2 ). In this work we report the experimental measurement and correlation of the solubility of Irgacure ® 2959 in scCO 2 . Results were obtained using a static analytical method, at 308.2, 318.2 and 328.2 K, and in a pressure range from 10.0 up to 26.0 MPa. Experimental data were correlated with three density-based models (Chrastil, Bartle and Méndez-Santiago-Teja models) and with an equation-of-state (EOS) model: the Peng-Robinson cubic equation of state (PR-EOS) together with the conventional van der Waals mixing and combining rules. Several different sets of solid properties, estimated by different methods available in literature, were used in EOS correlations. The importance of the estimation methods used for the determination of solid properties (namely sublimation pressure) was discussed in terms of correlation results quality.To the best of our knowledge, these are the first experimental scCO 2 solubility results for this class of initiators and the obtained solubility results indicate the feasibility of using this photoinitiator in free radical polymerization reactions carried out in scCO 2 like, for example, dispersion and precipitation polymerizations, or in the development of interpenetrating polymer networks (IPN's).

Solubility of Diflunisal in Supercritical Carbon Dioxide

“…A detailed description of this apparatus and of its validation was given in previous works. 27,28 The typical experimental procedure is described below.…”

Solubility of norfloxacin and ofloxacin in supercritical carbon dioxide

“…The experimental drug-scCO 2 equilibrium solubility data were measured according to the static method using an apparatus that was previously described in detail [23][24][25][26][27]. It is comprised by a high-pressure stainless-steel equilibrium cell (HPC) with an internal volume of approximately 30 cm 3 which is loaded with an excess amount (∼400 mg) of each solid substance (norfloxacin or ofloxacin) and a magnetic stirrer.…”

“…In this equation, P ref is a standard pressure (set to 1 bar) and a 1 , a 2 , A and C are empirical constants, determined from the fitting of experimental solubility data of each isotherm to obtain the values of A and C as previously detailed [23][24][25][26][27]. Notice that in this case the reference density ref was taken as the critical density of carbon dioxide.…”

“…The parameters k, ˛ and ˇ are obtained by performing a multiple regression of experimental solubility data as previously described [23][24][25][26][27].…”

Modified quadrupole Cubic Plus Association Equation of State (mqCPA EoS) for thermodynamic modeling of polymer-supercritical CO2 systems

“…However, in the other group of works, i.e. polymer-scCO 2 systems, the polymer is solubilized in scCO 2 [7][8][9][10] which limited studies have been reported for this type of systems. Determination of the cloud point pressure of the polymer-scCO 2 system is a key point for application of such systems in EOR processes.…”