Anionic Polymerization of the Barium Salt of One-Ended Living Polystyrene. 2. The Effect of Added Barium Tetraphenylboride

1977 ◽  
Vol 10 (3) ◽  
pp. 598-602 ◽  
Author(s):  
B. De Groof ◽  
W. Mortier ◽  
M. Van Beylen ◽  
M. Szwarc
Keyword(s):  
Anionic Polymerization ◽  
Barium Salt

Fluorocitrate Neural Dystrophy of the Guinea Pig Cochlea

1975 ◽  
Vol 33 ◽  
pp. 368-369
Author(s):  
G.J. Spector ◽  
C.D. Carr ◽  
I. Kaufman Arenberg ◽  
R.H. Maisel
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Sodium Phosphate ◽  
Sensory Cells ◽  
Barium Salt ◽  
Perfusion Medium ◽  
Cochlear Hair Cells ◽  
Neural Degeneration ◽  
Sodium Phosphate Buffer ◽  
Cochlear Neurons

All studies on primary neural degeneration in the cochlea have evaluated the end stages of degeneration or the indiscriminate destruction of both sensory cells and cochlear neurons. We have developed a model which selectively simulates the dystrophic changes denoting cochlear neural degeneration while sparing the cochlear hair cells. Such a model can be used to define more precisely the mechanism of presbycusis or the hearing loss in aging man.Twenty-two pigmented guinea pigs (200-250 gm) were perfused by the perilymphatic route as live preparations using fluorocitrate in various concentrations (15-250 ug/cc) and at different incubation times (5-150 minutes). The barium salt of DL fluorocitrate, (C6H4O7F)2Ba3, was reacted with 1.0N sulfuric acid to precipitate the barium as a sulfate. The perfusion medium was prepared, just prior to use, as follows: sodium phosphate buffer 0.2M, pH 7.4 = 9cc; fluorocitrate = 15-200 mg/cc; and sucrose = 0.2M.

The anionic polymerization of cyanogen

1966 ◽  
Vol 31 (1) ◽  
pp. 243-251 ◽  
Author(s):  
J. Peška ◽  
M. J. Beneš ◽  
O. Wichterle
Keyword(s):  
Anionic Polymerization

Mechanism of the propagation step in the anionic polymerization of styrene

1980 ◽  
Vol 45 (4) ◽  
pp. 1047-1055 ◽  
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Experimental Data ◽  
Induction Period ◽  
Anionic Polymerization ◽  
Reactive Intermediate ◽  
Coordination Polymerization ◽  
Kinetic Dependence ◽  
Mathematical Solution ◽  
Slow Reaction

The paper is dealing with an investigation of the kinetic dependence of the propagation step in the anionic coordination polymerization of styrene in benzene at 303 K with "living" oligostyryllithium as initiator at the onset of the reaction. A short but distinct induction period was found, indicating a preceding slow reaction leading to the formation of a reactive intermediate, which behaves as the initiator of the reaction. Using results obtained in the first paper of this series, a new mechanism of propagation has been suggested, the mathematical solution of which is correlated with experimental data.

Kinetic Modelling of Anionic Polymerization Involving a Dynamic Equilibrium between Two Growth Centres with Different Growth Rates

1993 ◽  
Vol 58 (10) ◽  
pp. 2349-2361 ◽  
Author(s):  
Jaromír Jakeš
Keyword(s):  
Molecular Weight ◽  
Growth Rates ◽  
Anionic Polymerization ◽  
Dynamic Equilibrium ◽  
Kinetic Modelling ◽  
Polymerization Time ◽  
Fast State ◽  
Growth State ◽  
In The Beginning ◽  
Growth Centres

Kinetic modelling of the molecular weight distribution (MWD) of polymer obtained by an anionic polymerization with two types of growth centres in a dynamic equilibrium, having different growth rates and lifetimes comparable to the polymerization time, was made for low monomer conversions. On the basis of distribution of the growth centres according to the total time spent in the fast growth state, it was shown that MWD of the resulting polymer are mostly bimodal at the beginning of the polymerization and change to unimodal MWD at sufficiently high polymerization degrees depending on the equilibrization rate. When all centres are in the fast state in the beginning, MWD are essentially unimodal throughout. A hint of trimodality is observed in some cases, in an extent hardly detectable in real chromatograms. Hence, a polymodal MWD can be explained only when more than two growth centres with different growth rates are assumed.

Living Anionic Polymerization of 4-Halostyrenes

2021 ◽  
Vol 54 (3) ◽  
pp. 1489-1498
Author(s):  
Raita Goseki ◽  
Taro Koizumi ◽  
Reina Kurakake ◽  
Satoshi Uchida ◽  
Takashi Ishizone
Keyword(s):  
Anionic Polymerization ◽  
Living Anionic Polymerization
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