Kinetics of living radical polymerization of styrene with macromolecular initiator

Abstract

Kinetics of living radical polymerization of styrene in emulsion initiated by polypropylene hydroperoxide with triethylenetetramine is proposed on the basis of a two stage mechanism. In the first stage fast initiation and propagation occur on the surface of polypropylene. In the second stage continuous chain propagation without termination proceeds in polymer particles in the emulsion. Dependence of rate and degree of polymerization on reaction time, initiator and activator concentrations predicted by the kinetics are ascertained by experimental results. Each polymer particle in the emulsion is suggested to consist of one polymer molecule with a living chain end. Main requisites for the living nature of this system are probably fast and/or limited decomposition and heterogeneity of the initiator in the emulsion polymerization.

Stereospecific Living Radical Polymerization: Dual Control of Chain Length and Tacticity for Precision Polymer Synthesis

“…65,66 Another way to reduce the termination reactions is to use some confined space, such as particles, in emulsion polymerization, where compartmentalization of the radical species prevents the encounter with another growing radical chain end in the other particle. This more or less physical approach to living radical polymerization was advocated in the 1970s and successfully employed for the synthesis of polymers with narrow molecular weight distributions (MWDs) and diblock and triblock copolymers by using a heterogeneous polymer initiator, [67][68][69][70] which might induce a very fast propagation and was removed by filtration once the polymerization started. However, this system has several drawbacks, such as difficulties in the procedures and obtaining the polymers with predictable molecular weights as well as the limitations to emulsion systems for styrene-based polymerizations.…”

Controlled Radical Polymerization Initiated by Solvated Electrons

“…mediums. [35,36] In addition, the external field regulated CRPs by light, electricity, and magnetic field, etc. have attracted much attention, because of the abilities in spatial and temporal controls.…”

“…[ 31,32 ] The others are performed by complexing radicals with Lewis acids, [ 33,34 ] and physically compartmentalizing radicals in heterogeneous mediums. [ 35,36 ] In addition, the external field regulated CRPs by light, electricity, and magnetic field, etc. have attracted much attention, because of the abilities in spatial and temporal controls.…”

Time-resolved gel permeation chromatographic study on poly(N-isopropylacrylamide)-block-poly(ethylene glycol) prepared by soap-free emulsion polymerization

“…Emulsion polymerization is known to provide narrowlydispersed polymers as compared to solution polymerization [1]. To experimentally elucidate the living nature of emulsion polymerization, we investigated soap-free emulsion polymerization by time-resolved gel permeation chromatographic (GPC) measurements observing timeevolutions of the monomer conversion and molecular weight.…”