Achieving high conversions in nitroxide‐mediated living styrene miniemulsion polymerization

Lin, Marcus; Cunningham, Michael F.; Keoshkerian, Barkev

doi:10.1002/masy.200450221

Cited by 20 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The STY‐1 reaction process was repeated in this reaction, except 1.8 g ascorbic acid was added to the STY‐1 formulation as a reaction accelerant to increase reaction rate and conversion 39. The ascorbic acid was mixed into the miniemulsion mixture after latex dispersion in the Niro Soavi homogenizer and 10 min before the latex was charged into the storage cylinders in the apparatus.…”

Section: Experimental Partmentioning

confidence: 99%

Nitroxide‐Mediated Bulk and Miniemulsion Polymerization in a Continuous Tubular Reactor: Synthesis of Homo‐, Di‐ and Triblock Copolymers

Enright¹,

Cunningham²,

Keoshkerian³

2010

Macro Reaction Engineering

Self Cite

View full text Add to dashboard Cite

In previous work, a modified nitroxide‐mediated miniemulsion polymerization was demonstrated in a continuous tubular reactor to prepare a latex of polystyrene homopolymer dispersed in water. There, the initial reaction step (low conversion bulk polymerization to prepare the macroinitiator) was done in a batch reactor while the miniemulsion polymerization step was done in a continuous tubular reactor. The present paper describes an extension of that work in which all the reaction steps have been achieved in the continuous tubular reactor. Chain extension of the polystyrene latex to give polystyrene‐block‐poly(butyl acrylate) diblock and polystyrene‐block‐poly(butyl acrylate)‐block‐polystyrene triblock copolymers is also described.

show abstract

Section: Experimental Partmentioning

confidence: 99%

Nitroxide‐Mediated Bulk and Miniemulsion Polymerization in a Continuous Tubular Reactor: Synthesis of Homo‐, Di‐ and Triblock Copolymers

Enright¹,

Cunningham²,

Keoshkerian³

2010

Macro Reaction Engineering

Self Cite

View full text Add to dashboard Cite

show abstract

“…In most cases, S/TEMPO miniemulsion polymerizations using macroinitiator (polystyrene (PS)-TEMPO), [21,22] benzoyl peroxide/ TEMPO [23,24] or potassium persulfate/TEMPO [24][25][26][27] give R p values very similar to those in bulk. [28] Cunningham and coworkers [29,30] reported a strong dependence of R p in S/PS-TEMPO miniemulsion on the amount of the surfactant sodium dodecylbenzenesulfonate (SDBS) (the particle size distributions were ''nearly identical'' with a ''mean diameter'' of 150 nm), and speculated that SDBS or SDBS impurities consume nitroxide, thus resulting in an increase in R p . [29] Pan et al [31] reported that in the TEMPO-mediated thermal miniemulsion polymerization of S at 125 8C, the initial R p was approx.…”

Section: Introductionmentioning

confidence: 99%

Particle Size Effects in TEMPO‐Mediated Radical Polymerization of Styrene in Aqueous Miniemulsion

Nakamura

Zetterlund

Okubo

2006

Macromol. Rapid Commun.

View full text Add to dashboard Cite

Summary: 2,2,6,6‐Tetramethylpiperidinyl‐1‐oxy (TEMPO)‐mediated radical polymerization of styrene in aqueous miniemulsion at 125 °C using sodium dodecylbenzenesulfonate and poly(vinyl alcohol), respectively, as colloidal stabilizers has been investigated. The particle size had a dramatic effect on the polymerization process. Decreasing particle size led to a markedly higher polymerization rate, but less control and a lower degree of livingness. For particles with diameters greater than approximately 170 nm, the polymerization behavior was essentially the same as in the corresponding bulk system. By varying the particle size within an appropriate range, it is possible to tune the polymerization such that the polymerization rate is increased while still maintaining reasonable control and livingness.magnified image

show abstract

“…Therefore, the disadvantage of increasing the rate (greater termination rates) is partially or wholly offset by reduced disproportionation rates. We have not optimized the initiator addition process; it may in fact be possible to achieve higher livingness with the modified recipe, as has been found in mini‐emulsion SFRP 21…”

Section: Resultsmentioning

confidence: 99%

A Semi‐Batch Process for Nitroxide Mediated Radical Polymerization

Wang

Hutchinson

Cunningham

2005

Macro Materials & Eng

Self Cite

View full text Add to dashboard Cite

Summary: A semi‐batch process using nitroxide mediated polymerization, was explored for the design of low molecular weight solvent‐borne coatings, typical of those used in the automotive industry. While living radical polymerization (LRP) offers many advantages in the control of polymer chain microstructure that may confer important physical and chemical property benefits to coatings, adapting LRP to a semi‐batch process poses significant challenges in the design and operation of the process. Using styrene monomer, various two‐component initiating systems (free radical initiator, 4‐hydroxy‐TEMPO) were studied to understand the effects of different initiators on the course of polymerization. In addition, an alkoxyamine was synthesized and used as the initiating source. The initiators Luperox 7M75 and Luperox 231 give higher polymerization rates and reasonable control over polymerization, while benzoyl peroxide (BPO), Vazo 67, and the alkoxyamine are less effective. The number of polymer chains in the final product is always less than the theoretical value, reflecting poor initiation efficiency, probably resulting from undesirable termination reactions that become important due to the nature of the semi‐batch process. Adding camphorsulfonic acid (CSA) or charging initiator concurrently with monomer during semi‐batch feed, can increase the polymerization rate while maintaining the living character of the polymerization. The copolymerization of styrene and butyl acrylate is also shown to exhibit living character.Schematic representation of the exchange reaction to produce N‐TEMPO capped polymer chains.magnified imageSchematic representation of the exchange reaction to produce N‐TEMPO capped polymer chains.

show abstract

Achieving high conversions in nitroxide‐mediated living styrene miniemulsion polymerization

Cited by 20 publications

References 0 publications

Nitroxide‐Mediated Bulk and Miniemulsion Polymerization in a Continuous Tubular Reactor: Synthesis of Homo‐, Di‐ and Triblock Copolymers

Nitroxide‐Mediated Bulk and Miniemulsion Polymerization in a Continuous Tubular Reactor: Synthesis of Homo‐, Di‐ and Triblock Copolymers

Particle Size Effects in TEMPO‐Mediated Radical Polymerization of Styrene in Aqueous Miniemulsion

A Semi‐Batch Process for Nitroxide Mediated Radical Polymerization

Contact Info

Product

Resources

About