Controlled Radical Polymerization in Aqueous Dispersed Media

2006 ◽  
Vol 59 (10) ◽  
pp. 693 ◽  
Author(s):  
Maud Save ◽  
Yohann Guillaneuf ◽  
Robert G. Gilbert
Keyword(s):  
Free Radical ◽  
Emulsion Polymerization ◽  
Radical Polymerization ◽  
Large Scale ◽  
Colloidal Stability ◽  
Free Radical Polymerization ◽  
Controlled Radical Polymerization ◽  
Wide Range ◽  
Dispersed Media ◽  
Aqueous Dispersed Media

Controlled radical polymerization (CRP), sometimes also termed ‘living’ radical polymerization, offers the potential to create a wide range of polymer architectures, and its implementation in aqueous dispersed media (e.g. emulsion polymerization, used on a vast scale industrially) opens the way to large-scale manufacture of products based on this technique. Until recently, implementing CRP in aqueous dispersed media was plagued with problems such as loss of ‘living’ character and loss of colloidal stability. This review examines the basic mechanistic processes in free-radical polymerization in aqueous dispersed media (e.g. emulsion polymerization), and then examines, through this mechanistic understanding, the new techniques that have been developed over the last few years to implement CRP successfully in emulsion polymerizations and related processes. The strategies leading to these successes can thus be understood in terms of the various mechanisms which dominate CRP systems in dispersed media; these mechanisms are sometimes quite different from those in conventional free-radical polymerization in these media.

scholarly journals Methylenelactide: vinyl polymerization and spatial reactivity effects

2016 ◽  
Vol 12 ◽  
pp. 2378-2389 ◽  
Author(s):  
Judita Britner ◽  
Helmut Ritter
Keyword(s):  
Free Radical ◽  
Methyl Methacrylate ◽  
Radical Polymerization ◽  
Chain Transfer ◽  
Free Radical Polymerization ◽  
Controlled Radical Polymerization ◽  
Experimental Results ◽  
Cyclic Monomer ◽  
Vinyl Polymerization ◽  
Reversible Addition

The first detailed study on free-radical polymerization, copolymerization and controlled radical polymerization of the cyclic push–pull-type monomer methylenelactide in comparison to the non-cyclic monomer α-acetoxyacrylate is described. The experimental results revealed that methylenelactide undergoes a self-initiated polymerization. The copolymerization parameters of methylenelactide and styrene as well as methyl methacrylate were determined. To predict the copolymerization behavior with other classes of monomers, Q and e values were calculated. Further, reversible addition fragmentation chain transfer (RAFT)-controlled homopolymerization of methylenelactide and copolymerization with N,N-dimethylacrylamide was performed at 70 °C in 1,4-dioxane using AIBN as initiator and 2-(((ethylthio)carbonothioyl)thio)-2-methylpropanoic acid as a transfer agent.

scholarly journals Molecular Weight Distribution Generated on Initiation of Free Radical Polymerization by Sequence of Laser Pulses

1995 ◽  
Vol 16 (2) ◽  
pp. 83-99 ◽  
Author(s):  
A. V. Evseev ◽  
A. N. Nikitin
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Radical Polymerization ◽  
Free Radical Polymerization ◽  
Laser Pulses ◽  
Stationary Regime ◽  
Arbitrary Sequence ◽  
Wide Range ◽  
Before And After ◽  
Short Laser Pulses

An investigation of molecular weight distributions (MWDs) resulting from initiation of free radical polymerization by an arbitrary sequence of short laser pulses has been undertaken. The analytical expressions have been derived to calculate MWDs for a polymerization scheme that contains reactions of chain initiation, propagation and termination by recombination or disproportionation. The MWDs produced by pulse-periodic irradiation have been calculated for a wide range of initiating pulses repetition rates (f = 0.05–100 Hz). The MWD dynamics in the act of polymerization and the influence of the duration of polymerization pseudostationary regime establishment upon the MWD have also been studied. The suitability of the derived expressions for describing the MWD generated by CW radiation before and after the establishment of polymerization quasi-stationary regime has been considered.

scholarly journals Atom transfer radical polymerization in aqueous dispersed media

2009 ◽  
Vol 7 (4) ◽  
pp. 657-674 ◽  
Author(s):  
Ke Min ◽  
Krzysztof Matyjaszewski
Keyword(s):  
Molecular Weight ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Colloidal Stability ◽  
Atom Transfer ◽  
Recent Developments ◽  
Dispersed Media ◽  
Aqueous Dispersed Media ◽  
Significant Attention ◽  
Important Progress

AbstractDuring the last decade, atom transfer radical polymerization (ATRP) received significant attention due to its exceptional capability of synthesizing polymers with pre-determined molecular weight, well-defined molecular architectures and various functionalities. It is economically and environmentally attractive to adopt ATRP to aqueous dispersed media, although the process is challenging. This review summarizes recent developments of conducting ATRP in aqueous dispersed media. The issues related to retaining “controlled/living” character as well as colloidal stability during the polymerization have to be considered. Better understanding the ATRP mechanism and development of new initiation techniques, such as activators generated by electron transfer (AGET) significantly facilitated ATRP in aqueous systems. This review covers the most important progress of ATRP in dispersed media from 1998 to 2009, including miniemulsion, microemulsion, emulsion, suspension and dispersed polymerization.

scholarly journals Surface Functionalization of Magnetic Nanoparticles Using a Thiol-Based Grafting-Through Approach

Surfaces ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 116-131
Author(s):  
Philip Biehl ◽  
Felix H. Schacher
Keyword(s):  
Free Radical ◽  
Magnetic Nanoparticles ◽  
Radical Polymerization ◽  
Shell Thickness ◽  
Free Radical Polymerization ◽  
Polymerization Process ◽  
Core Shell ◽  
Transmission Electron ◽  
Wide Range ◽  
Broad Variety

Here we describe a simple and straightforward synthesis of different multifunctional magnetic nanoparticles by using surface bound thiol-groups as transfer agents in a free radical polymerization process. The modification includes a first step of surface silanization with (3-mercaptopropyl)trimethoxysilane to obtain thiol-modified nanoparticles, which are further used as a platform for modification with a broad variety of polymers. The silanization was optimized in terms of shell thickness and particle size distribution, and the obtained materials were investigated by dynamic light scattering (DLS), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). Subsequently, the free radical polymerization of different monomers (tert-butyl acrylate (tBA), methyl methacrylate (MMA), styrene, 2-vinyl pyridine (2VP), and N-isopropylacrylamide (NIPAAm)) was examined in the presence of the thiol-modified nanoparticles. During the process, a covalently anchored polymeric shell was formed and the resulting core–shell hybrid materials were analyzed in terms of size (DLS, TEM), shell thickness (TGA, TEM), and the presence of functional groups (attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FT-IR)). Hereby, the shell leads to a different solution behavior of the particles and in some cases an increased stability towards acids. Moreover, we examined the influence of the nanoparticle concentration during polymerization and we found a significant influence on dispersity of the resulting polymers. Finally, we compared the characteristics of the surface bound polymer and polymer formed in solution for the case of polystyrene. The herein presented approach provides straightforward access to a wide range of core–shell nanocomposites.

Synthesis of a novel silicone based copolymeric surfactant and application in emulsion polymerization

2013 ◽  
Vol 33 (9) ◽  
pp. 813-821
Author(s):  
Hamid Javaherian Naghash ◽  
Mohammad Hossein Sheikhbahaei
Keyword(s):  
Surface Tension ◽  
Free Radical ◽  
Emulsion Polymerization ◽  
Radical Polymerization ◽  
Surface Activity ◽  
Diethylene Glycol ◽  
Polyvinyl Acetate ◽  
Free Radical Polymerization ◽  
Emulsion Copolymerization ◽  
Acrylic Monomer

Abstract A novel silicone-containing acrylic monomer, trimethylsiloxybutoxy dimethylsiloxybutyl acrylate (TSBA) and diethylene glycol monoallyl ether (DGME) was synthesized successfully. Then, a novel copolymeric surfactant was prepared by the free radical polymerization of TSBA and DGME in the presence of dioxane and azobisisobutyronitrile (AIBN) as a solvent and initiator, respectively. Next, a series of polyvinyl acetate (PVAc), 2-ethylhexyl acrylate (2-EHA) and polystyrene (PSt) latexes were successfully synthesized, each one throughout by the emulsion copolymerization in the presence of a copolymeric surfactant. This copolymeric surfactant exhibited excellent surface activity and the surface tension decreased with an increase in the concentration of the copolymeric surfactant.

scholarly journals On the mechanism of acrylamide emulsion polymerization with the participation of its dimers

2021 ◽  
pp. 50-56
Author(s):  
L.R. Harutyunyan ◽  
◽  
R.S. Harutyunyan ◽  
Keyword(s):  
Free Radical ◽  
Emulsion Polymerization ◽  
Radical Polymerization ◽  
Reaction Order ◽  
Free Radical Polymerization ◽  
Water Soluble ◽  
Polymerization Mechanism ◽  
Low Concentrations ◽  
Acrylamide Monomer

The role of both dimeric and monomeric forms of acrylamide monomer in the process of polymerization in emulsions initiated by different type of initiators was discussed and the reasons for the reaction order with respect to monomer greater than unity were elucidated for acrylamide free radical polymerization in emulsions. The emulsion polymerization mechanism of acrylamide is discussed separately for the processes initiated by water-soluble initiator and oil-soluble initiator. The main difference in two cases is the distribution of acrylamide and initiator in aqueous and toluene phases. In the case of using water-soluble initiator, the initiator and acrylamide are in the same phase, whereas the molecules of the initiator and acrylamide are distributed between different phases in the case of using oil-soluble initiator. As a result, the participation of the dimers in the process of acrylamide emulsion polymerization is more efficient for the system where water-soluble initiator is used. For that system, it is suggested that both dimers and monomers of acrylamide participate in the propagation reaction at relatively low concentrations of acrylamide, which explains the value of the reaction order with respect to monomer greater than unity.

Sign in / Sign up

Export Citation Format

Share Document