Free‐radical bulk polymerization of styrene with a new trifunctional cyclic peroxide initiator

Abstract

ABSTRACT:The bulk free-radical polymerization of styrene in the presence of a new cyclic trifunctional initiator, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane, was studied. Full-conversion-range experiments were carried out to assess the effects of the temperature and initiator concentration on the polymerization kinetics, molecular weight, and polydispersity. Gel permeation chromatography was used to measure the molecular weight and the molecular weight distribution of polystyrene. When this multifunctional initiator was used for styrene polymerization at higher temperatures, it was possible to produce polymers with higher molecular weights and narrower molecular weight polydispersity at a higher rate. This showed that the molecular weight and polydispersity were influenced by the initiator concentration and the polymerization temperature in an unusual manner. Moreover, polystyrene, obtained with trifunctional peroxide, had OOO bonds in the molecular chains and was investigated with differential scanning calorimetry and gel permeation chromatography.

Effect of ionic liquid on the thermal decomposition of cyclic organic peroxides

“…The kinetic data obtained in this work, and other results previously described by various authors for different cyclic peroxides (Cafferata et al, 1984;Cafferata et al, 1990;Cafferata et al, 1991;Eyler et al, 1994;Eyler et al, 2000;Barreto and Cañizo, 2004;Sheng et al, 2004;Cañizo, 2006;Iglesias et al, 2009), allowed to associate the rate constants with the unimolecular rupture process of one peroxidic bond as the rate-determining step of the decomposition route (Scheme 2).…”

“…Cyclic organic peroxides, belonging to the 1,2,4,5-tetraoxacyclohexanes and 1,2,4,5,7,8-hexaoxacyclononanes substituted families have gained great importance over the last years due to their reactivity and particular behavior in different polymeric systems (Cerna et al, 2002;Sheng et al, 2004;Cañizo, 2006;Tasca et al, 2012;Nesprias et al, 2013;Barreto et al, 2014). These authors proposed the homolytic cleavage of the O-O bond during the decomposition process of these compounds, generating a biradical intermediate, which can act as an initiator in the free radical polymerization of vinyl monomers.…”

Mathematical Modeling of Molecular Weight Distributions in Vinyl Chloride Suspension Polymerizations Performed with a Bifunctional Initiator through Probability Generating Functions

“…Since the second half of the 1980 s, several experimental studies and mathematical models regarding the use of multifunctional free radical initiators have been reported, mostly related to the production of poly(styrene) (PS), poly(methyl methacrylate) (PMMA), poly(vinyl acetate) (PVAc), and styrene/methacrylate copolymers . In most cases, polymerizations have been performed in bulk or solution processes.…”

“…The main factor that has prevented the widespread use of bifunctional initiators in vinyl chloride polymerization processes is the low rate of thermal decomposition of most commercially available initiators at the feasible PVC process temperatures (40–60 °C). The vast majority of commercial multifunctional peroxides are used at reaction temperatures above 90 °C . The lack of further studies regarding the use of multifunctional initiators in vinyl chloride free radical polymerizations is very intriguing, since the available results highlighted the potential benefits of using multifunctional initiators in PVC processes.…”

Recent Advances in the Study of Multifunctional Initiators in Free Radical Polymerizations

“…Recently, cyclic multifunctional initiators have been investigated in free radical polymerizations 26,27. During polymerization, the decomposition of one labile group opens the ring to form a linear di‐radical chain as shown in Figure 2.…”