Incorporation Behavior of Nonionic Emulsifiers inside Particles and Secondary Particle Nucleation during Emulsion Polymerization of Styrene

Abstract

In previous studies, it was found that a large amount of the polyoxyethylene nonylphenyl ether nonionic emulsifier, Emulgen 911 (E911), was incorporated inside polymer particles obtained at the completion of a conventional emulsion polymerization with potassium persulfate as a typical water-soluble initiator. In this study, to understand the incorporation phenomenon in more detail, the incorporation behavior during a batch emulsion polymerization of styrene was investigated. The percentage of E911 incorporated inside polystyrene (PS) particles relative to the total weight of E911 used in the polymerization increased to 18% until 50% conversion and then decreased and levelled off to 13% at 70−80% conversion. A similar incorporation behavior was observed in a seeded emulsion polymerization of styrene, in which E911 was added to an emulsifier-free PS seed emulsion to set the same E911 concentration as the batch emulsion polymerization before swelling of the PS seed particles with styrene at 70 °C for 24 h. These indicate that E911 molecules absorbed once into styrene-swollen PS particles partially exited therefrom into the aqueous medium during the polymerizations. When the E911 concentration in the aqueous medium is kept above the critical micelle concentration for a long period by the repartitioning process of E911 from styrene droplets into styrene-swollen particles via aqueous medium and/or exiting from the styrene-swollen particles into the aqueous medium, secondary particle nucleation continues during the polymerization, resulting in PS particles having a broad size distribution.

Facile Access to High Solid Content Monodispersed Microspheres via Dual‐Component Surfactants Regulation toward High‐Performance Colloidal Photonic Crystals

“…The linear correlation between the volume (D 3 ) of microspheres and the adding amount of St in the second stage is shown in Figure S5, Supporting Information, which indicates the absence of secondary nucleation at the “microsphere growth” stage. [ 40 ] However, overly increasing the amount of monomer will inevitably break the balance of inter‐microsphere forces, resulting in gelation and polydispersion (Table S1, Supporting Information). In addition, it has been proved that the surfactant plays a dominant role in regulating the SC and monodispersity of microspheres, where the SDS contributes significantly to microsphere nucleation, and the nonionic surfactant (CO897) promotes the growth of microspheres.…”

Roles of Proton in the Formation of Microspheres: Precipitation Polymerization of Styrene in Alcohols by Using AIBN as Initiator

“…[27][28][29][30] In fact, such a conclusion has been reported in the heterophase polymerizations. [31,32] The amounts of consumed stabilizer, polyvinyl pyrrolidone (PVP), in the dispersion polymerization of MMA [31] and nonionic surfactant Emulgen 911 in the emulsion polymerization of St, respectively, [32] are much smaller than those predicted according to the saturated adsorption on the hydrophobic surface of particles. Most of surfactants remain in the aqueous phase.…”

“…Song et al directly demonstrated the monomer transfer by the collision-incorporation of growing particles with the fluorescent PMMA submicron particles as seed in the seeded dispersion polymerization of MMA. [11,12] On the other hand, the continuous nucleation throughout the entire heterophase polymerizations until the monomer phase disappears has been a consensus, [2][3][4][5][6][11][12][13][14] which definitely rebuts the Smith-Ewart theory. [1] However, the role of surfactants and their aggregation, i. e. micelles, are so far unclear in Ni's description.…”

Multifunctional Polymer Particles Containing Quaternary Ammonium for Antimicrobial Particulate Surfactants and Defoaming

“…Because of its surfactant-free character, Pickering emulsion is attractive for several applications, including pharmaceutics, drug delivery, , cosmetics, , and the food industry. − A polymer particle is one of the most famous particulate surfactants used in Pickering emulsion because its particle surface can be functionalized for further appropriated applications. One of the most commonly used polymer particle preparation techniques is emulsion conventional radical polymerization (emulsion CRP). − It is an environmentally friendly technique using water as the continuous phase, and it is easy to scale up. However, the obtained polymer particles may contain emulsifiers, which often causes various product quality issues, including environmental pollution.…”