Free‐radical polymerization of methyl methacrylate in the presence of trialkylboranes

Brindley, P. B.; Pearson, Ralph G.

doi:10.1002/pol.1968.110061202

Cited by 10 publications

(6 citation statements)

References 9 publications

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“…in single crystals of copperzinc,75,100 copper-indium, 76 and iron-,chromium 8 0 very large values may be -obtained. This difference could arise be-,cause of the very low rates of work-hardening associated with the deformation of face--centred cubic alloy single crystals 74 ,75 and also because of the possible contribution of :geometrical softening in alloy single crystals.1o, 74,75 It is observed generally that the lower -yield stress, the Liiders strain, and ky all increase at higher solute contents. 64 ,101 However, the reason for this is not at all ,clear at the present time.…”

Section: Discussionmentioning

confidence: 99%

“…It may be that the reduced rate of work-hardening is important, as observed in copper-zinc. 75 . Also the temperature-dependence increases with larger solute contents which suggests that n in equation [1] may decrease.…”

Section: Discussionmentioning

confidence: 99%

“…61 However, this has not been found in copper-zinc single crystals. 75 Unlike polycrystals, the strain to the onset of serrations in aluminium :3 0/0 magnesium single crystals proves to be independent of temperature,61 which is difficult to explain on the basis of current theoretical ideas, although a systematic trend was observed when only 0·7at.-%Mg vvas present. 121 The temperature range over which the serrations occur does, however, seem to be comparable in single crystals and polycrystals, although the serrations persist to higher temperatures in single crystals .…”

Section: The Effect Of Grain Sizementioning

confidence: 98%

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Yield-point phenomena in substitutional alloys

Brindley¹,

Worthington²

1970

Metallurgical Reviews

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A material exhibits a yield point when a larger stress is required to initiate deformation by slip than to continue it. In a normal tensile test this is usually observed as a drop in load at the start of gross yielding. Load drops may also be observed that are due to deformation twinning, but this will not be discussed here. Annealed mild steel was once thought to be unique in showing an initial yield point but it is now known that the effect is quite general, and many examples occur in substitutional alloys.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: The Effect Of Grain Sizementioning

confidence: 98%

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Yield-point phenomena in substitutional alloys

Brindley¹,

Worthington²

1970

Metallurgical Reviews

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“…In the earliest work on borane autoxidation, Grummitt showed that partially oxidised butylboronic anhydride and dioxygen would initiate the polymerisation of vinyl acetate at 70 °C, 27 and there are many subsequent examples of the use of the system for initiating homolytic polymerisation. [91][92][93] Boranes, in the presence of a trace of air or dioxygen, are now widely used as radical initiators, but despite this growing importance, no attempt appears to have been made to determine which particular initiation process is involved.…”

Section: Organoboranes As Radical Initiators and Radical Reagentsmentioning

confidence: 99%

Autoxidation of Organoboranes and Related Organometallics: Radicals and their Ramifications

Davies

2008

Journal of Chemical Research

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The identification, 50 years ago, of the autoxidation products of organoboranes as organoperoxyboranes, and of the mechanism of the reaction as a radical chain, has had far-reaching consequences in organometallic and organic chemistry in the identification of organic radicals and of other radical reactions, in the use of organoboron compounds in synthesis and catalysis, in the parallel chemistry of other metals (particularly, currently, of zinc), and of the behaviour of metals as hydrogen equivalents. This review traces the course of some of those developments in the radical chemistry of compounds in which oxygen forms a bond with boron and related metals, and summarises the present position.

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“…The above authors concluded that the polymerization of MMA by tri-n-butylborane proceeds via a radical mechanism, and also that the amino acid esters act as electron donors. It has been reported that 4-methoxy-6-tert-butylphenol (BHA), a most effective inhibitor of a number of common phenolic antioxidants, exhibits no inhibitory effect on auto-oxidation of tri-sec-butylborane in benzene, whereas among phenolic antioxidants, galvinoxyl alone exhibits an inhibitory effect in this setting; there is a very slow interaction between butylborane and galvinoxyl over a period of days [25]. Methyl tyrosinate seems to show no inhibitory effect in the tri-n-butylborane reaction system, even though it is a phenolic antioxidant.…”

Section: Amino Acidsmentioning

confidence: 99%

Tri-n-Butylborane/WaterComplex-Mediated Copolymerization of Methyl Methacrylate with Proteinaceous Materials and Proteins: A Review

Fujisawa

Kadoma

2010

Polymers

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Previous studies of tri-n-butylborane-initiated graft copolymerization of methyl methacrylates with hydrated proteinous materials and proteins have focused on the number of grafted-poly (MMA) branches as well as the percent graft and graft efficiency. The number of branches in silk fibroin is 1.3, whereas the number in collagen, gelatin, ovalbumin and wool are 0.1, 0.04, 0.02 and 0.03, respectively. The number of grafted-PMMA branches in synthetic poly-L-peptides is approximately 10-fold less than that in gelatin, and decline, in the order poly-Ala > poly-Ser > poly-Pro > poly-Glu > poly-Lys. By contrast, poly-Gly, poly-Tyr and poly-Leu have no branches. The co-catalytic effect (the ratio of the number of polymer formed relative to that of control) of amino acids on tri-n-butylborane-initiated polymerization of MMA in the presence of water has been linearly correlated with their ionization potential (IP koopman ); |Äå HOMO (Highest Occupied Molecular Orbital)| (r 2 = 0.6, outliers: Cys and His); Äå HOMO = [åHOMO aqua − åHOMO vacuum ] calculated using the semiempirical AM1 method. Also, a significant exponential relationship between the number of branches of poly-L-polypeptides and the Äå HOMO of the corresponding amino acids has been observed (r 2 = 0.9). A possible grafting site of protein (polypeptide) is discussed.

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Free‐radical polymerization of methyl methacrylate in the presence of trialkylboranes

Cited by 10 publications

References 9 publications

Yield-point phenomena in substitutional alloys

Yield-point phenomena in substitutional alloys

Autoxidation of Organoboranes and Related Organometallics: Radicals and their Ramifications

Tri-n-Butylborane/WaterComplex-Mediated Copolymerization of Methyl Methacrylate with Proteinaceous Materials and Proteins: A Review

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