Reversible‐addition fragmentation chain transfer radical emulsion polymerization by a nanoprecipitation process

Abstract

Polymerizations of styrene under emulsion reversible‐addition fragmentation chain transfer polymerization conditions are reported. Using a recently developed nanoprecipitaiton process, emulsion particles were formed by the precipitation of an acetone solution of a macroRAFT agent into an aqueous solution of poly(vinyl alcohol). The particles were then swollen with monomer and subsequently polymerized. Emulsion polymerizations were performed at 65 and 75 °C in which either KPS, BPO, or a combination of both was used as an initiating source. Reactions were also performed at temperatures over 100 °C in which the thermal initiation of styrene was used as an initiating source. In all cases, the polymerizations proceeded in a living manner, yielding polymers that showed an incremental increase in molecular weight with time and had narrow molecular weight distributions. Plots of number‐ average molecular weight versus conversion were linear, indicating a controlled polymerization. The resulting latices were colloidally stable and gave particle size distributions with a typical average particle diameter in the 150 nm range. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5708–5718, 2006

Polymer Nanoparticles via Living Radical Polymerization in Aqueous Dispersions: Design and Applications

“…The understanding of kinetics and thermodynamic factors when using RAFT in aqueous dispersions allowed researchers to circumvent the issues of transportation and other issues by redesigning the system. The main aim for all these systems (e.g., miniemulsions, , nanoprecipitation, , self-assembly, and nanoreactors , ) was to colocalize the RAFT agent and monomer together to avoid transportation issues and provide some control of the particle size. In this section, we will discuss the self-assembly and nanoreactor techniques as they form the basis of creating 3D polymer structure in water.…”

Recent advances in controlled/living radical polymerization in emulsion and dispersion

“…14). 200 Recently, the nanoprecipitation method was also applied to RAFT 201 and ATRP 202,203 emulsion polymerization systems, producing well-controlled homo and block copolymers in stable latex particles.…”

Living Radical ab Initio Emulsion Polymerization of n-Butyl Acrylate by Reverse Iodine Transfer Polymerization (RITP): Use of Persulfate as Both Initiator and Oxidant

“…Acetone was removed by rotary evaporation; the latex was swollen with monomer and then polymerized. 17 Concerning multistep procedures, emulsion polymerization was achieved by using an amphiphatic RAFT agent which can mediate polymerization in both aqueous and organic phases. This RAFT agent was first involved in the aqueous phase polymerization of the watersoluble acrylic acid to a low degree of polymerization.…”

“…In seeded emulsion polymerization, a highly hydophobic RAFT agent was transported through the aqueous phase to the polymer particles thanks to the addition of acetone as cosolvent, and acetone was then removed by rotary evaporation prior to polymerization. , A similar system has been developed where the seed particles were prepared by nanoprecipitation of an acetone solution of a macroRAFT agent into an aqueous solution of poly(vinyl alcohol). Acetone was removed by rotary evaporation; the latex was swollen with monomer and then polymerized . Concerning multistep procedures, emulsion polymerization was achieved by using an amphiphatic RAFT agent which can mediate polymerization in both aqueous and organic phases.…”