Solvent-Free Stable Free Radical Polymerization: Understanding and Applications

Odell, Peter G.; Listigovers, Nancy A.; Quinlan, Marion H.; Georges, Michaël K.

doi:10.1021/bk-1998-0713.ch005

Cited by 9 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In most cases, using TEMPO or 4‐oxo‐TEMPO as a stable free radical, attempts to obtain higher molecular weight and narrow molecular weight distribution of polyacrylate homopolymers or block copolymers have proved difficult, as mentioned in many studies,28–30 the reason being the reproduction of nitroxide during the polymerization which can retard the growth of polymer chains. In our previous study,22 an equation was derived to express the relationship between ln([M] 0 /[M]) and reaction time (Eqn (27)) when the 4‐oxo‐TEMPO‐mediated polymerization is strongly influenced by the hydrogen transfer reaction of hydroxylamine (4‐oxo‐TEMPOH) to the propagating radical.…”

Section: Resultsmentioning

confidence: 99%

Influence of DMF on the polymerization of tert‐butyl acrylate initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator

Kuo

Chiu

Cheng

2008

Polymer International

View full text Add to dashboard Cite

BACKGROUND: In a number of studies it has been shown that 2,2,6,6‐tetramethylpiperidinooxy (TEMPO)‐mediated polymerization of acrylates is not facile. Therefore, the object of the study reported here was to prepare poly[styrene‐block‐(tert‐butyl acrylate)] (PS‐b‐PtBA) block copolymers using 4‐oxo‐TEMPO‐capped polystyrene macroinitiator as an initiator, in the presence of small amounts of N,N‐dimethylformamide (DMF). The kinetic analysis and the effect of DMF on the reaction mechanism are also discussed. RESULTS: PS‐b‐PtBA block copolymer was prepared through polymerization of tert‐butyl acrylate (tBA) initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator at 135 °C. The polymerization rate of tBA could be increased by adding a small amount of DMF, and the number average molecular weight of the PtBA block in PS‐b‐PtBA reached 10 000 g mol−1 with narrow polydispersity. The activation rate constant kact−tBA of alkoxyamine increased and the recombination rate constant krec−tBA decreased with increasing DMF concentration. CONCLUSION: DMF was shown to be a rate‐enhancing additive for the polymerization of tBA using a 4‐oxo‐TEMPO‐capped polystyrene macroinitiator. From the kinetic analysis, it was concluded that the improvement of polymerization with the addition of DMF was due to an increase in kact−tBA and a decrease in krec−tBA. Copyright © 2008 Society of Chemical Industry

show abstract

Section: Resultsmentioning

confidence: 99%

Influence of DMF on the polymerization of tert‐butyl acrylate initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator

Kuo

Chiu

Cheng

2008

Polymer International

View full text Add to dashboard Cite

show abstract

“…The preparation of polystyrene by stable free radical polymerization (SFRP) is well studied using tetramethylpiperidine- N -oxide (TEMPO) derived initiators and related systems . Hence, proper incorporation of crown ether moieties into TEMPO initiators offers a means of introducing these host moieties efficiently and selectively at the chain ends, while controlling the molecular weight distributions so as ultimately to produce phase separated morphologies in the resulting self-assembled copolymers.…”

Section: Resultsmentioning

confidence: 99%

Syntheses and Model Complexation Studies of Well-Defined Crown Terminated Polymers

Gibson

Huang

et al. 2005

Macromolecules

View full text Add to dashboard Cite

A TEMPO-based free radical initiator (4a) containing a dibenzo-24-crown-8 (DB24C8, 2a) moiety was synthesized. A similar initiator (4b) based on bis(m-phenylene)-32-crown-10 (BMP32C10, 1b) was also synthesized. The crown-based initiators were used to prepare crown ether terminated polystyrenes of narrow molecular weight distribution (PDI). The DB24C8-terminated polymer 5 was demonstrated to form a pseudorotaxane complex (18) with dibenzylammonium hexafluorophosphate (17), but because of its small cavity, 5 cannot complex bulky N,N‘-dialkyl-4,4‘-bipyridinium (paraquat or viologen) salts. On the other hand, the BMP32C10-terminated polymer 11 complexed N,N‘-bis(p-tert-butylbenzyl)-4,4‘-pyridinium bis(hexafluorophosphate (paraquat salt, 23) strongly, but did not interact with dibenzylammonium hexafluorophosphate (17) to a detectable extent. Therefore, these new polymeric hosts are capable macromolecular building blocks for supramacromolecular chemistry using pseudorotaxane complexation, and furthermore, both show selectivity; the DB24C8 polymer is selective for secondary ammonium ion complexation, and the BMP32C20 polymer is highly selective for paraquat recognition. Future work will involve application of these new functional polymers to preparation of star, graft, and block structures by self-assembly.

show abstract

“…However, the polymerization of BA at low temperature (125–130°C) was unsuccessful in many studies 3, 4, 12, 33. Because the acrylate/TEMPO bonds were too strong to break at a reasonable rate at temperatures 125–130°C to allow the propagation of monomer to continue, namely, the activation rate constant of acrylate/TEMPO bonds was smaller than that of styrene/TEMPO bonds.…”

Section: Resultsmentioning

confidence: 99%

“…The reaction mixture was preheated to 95°C for 3.5 h to let BPO decompose completely and then the polymerization was carried out at 123°C for 69 h. The narrow molecular weight distribution of polystyrene could be obtained. However, using TEMPO as a stable free radical, attempt to obtain high molecular weight and narrow molecular weight distribution of polyacrylate homo or block copolymer was not facile in many studies 3, 4, 12, 13. It was believed that the capping rate of acrylate by TEMPO is faster in comparison with the styrene system.…”

Section: Introductionmentioning

confidence: 99%

Preparation and kinetic analysis of PS‐b‐PBA block copolymer by 4‐oxo‐TEMPO capped polystyrene macroinitiators

Kuo

Chiu

Cheng

2009

J of Applied Polymer Sci

View full text Add to dashboard Cite

Polystyrene-block-poly(n-butyl acrylate) block copolymers were prepared from 4-oxo-2,2,6,6-tetramethylpiperidinooxy (4-oxo-TEMPO) capped polystyrene macroinitiators at a high temperature, 165 C. It was found that the number-average molecular weight of PBA chains in block copolymers could reach above 10,000 rapidly at early stage of polymerization with a narrow polydispersity index of 1.2-1.4, but after that, the polymerization seemed to be retarded. Furthermore, according to the kinetic analysis, the concentration of 4-oxo-TEMPO was increased mainly by the hydrogen transfer reaction of hydroxylamine (4-oxo-TEMPOH) to growing radicals during polymerization. This increase in 4-oxo-TEMPO concentration could retard the growth of polymer chains. The rate constant of the hydrogen transfer reaction of 4-oxo-TEMPOH to growing radicals, k H , estimated by the kinetic model is about 9.33 Â 10 4 M -1 s À1 at 165 C.

show abstract

Solvent-Free Stable Free Radical Polymerization: Understanding and Applications

Cited by 9 publications

References 0 publications

Influence of DMF on the polymerization of tert‐butyl acrylate initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator

Influence of DMF on the polymerization of tert‐butyl acrylate initiated by 4‐oxo‐TEMPO‐capped polystyrene macroinitiator

Syntheses and Model Complexation Studies of Well-Defined Crown Terminated Polymers

Preparation and kinetic analysis of PS‐b‐PBA block copolymer by 4‐oxo‐TEMPO capped polystyrene macroinitiators

Contact Info

Product

Resources

About