A Strategy for Increasing Molecular Weight of Polyester by Lipase-Catalyzed Polymerization

2001 ◽  
Vol 30 (8) ◽  
pp. 798-799 ◽  
Author(s):  
Hiroki Ebata ◽  
Kazunobu Toshima ◽  
Shuichi Matsumura
Keyword(s):  
Molecular Weight ◽  
Catalyzed Polymerization

scholarly journals Control of molecular weight in Ni(ii)-catalyzed polymerization via the reaction medium

2008 ◽  
pp. 4965 ◽  
Author(s):  
Damien Guironnet ◽  
Thomas Rünzi ◽  
Inigo Göttker-Schnetmann ◽  
Stefan Mecking
Keyword(s):  
Molecular Weight ◽  
Reaction Medium ◽  
Catalyzed Polymerization

THE MECHANISM OF SODIUM-INITIATED POLYMERIZATION OF DIOLEFINS

1948 ◽  
Vol 26b (9) ◽  
pp. 657-667 ◽  
Author(s):  
R. E. Robertson ◽  
Léo Marion
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
General Formula ◽  
Chain Termination ◽  
Low Molecular Weight ◽  
Initiation Of Polymerization ◽  
Catalyzed Polymerization

An analysis of the products of sodium-catalyzed polymerization of butadiene and isoprene in the presence of toluene suggests that initiation of polymerization takes place by the formation of a disodium addend rather than a free radical. The diaddend reacts with toluene to yield butene-2 and sodium benzyl. Since all of the low molecular weight polymers analyzed were shown to conform to the general formula C6H5CH2(monomer)nH, sodium benzyl is considered to be the chief chain initiator. Chain termination took place by reaction with toluene to regenerate the chain carrier, sodium benzyl. The nature of the acids separated on carbonation of a polymerizing system supports this conclusion.

THE EFFECT OF ALTERNATING ELECTRICAL FIELDS ON THE POLYMERIZATION OF STYRENE

1950 ◽  
Vol 28b (4) ◽  
pp. 117-131
Author(s):  
C. A. Winkler ◽  
W. A. Bryce ◽  
C. A. Genge
Keyword(s):  
Molecular Weight ◽  
Benzoyl Peroxide ◽  
Chemical Reactions ◽  
Average Molecular Weight ◽  
Electrical Fields ◽  
Inhibiting Effect ◽  
Rate Of Polymerization ◽  
Field Strengths ◽  
Catalyzed Polymerization

Equipment for studying the effects of alternating fields on chemical reactions is described. The catalyzed polymerization of liquid styrene was investigated, with fields of frequencies ranging from 1.15 to 7.72 Mc. and with field strengths up to 4500 v. per cm. The rate of polymerization was reduced by the application of the fields, the inhibition increasing approximately as the square of the voltage. The fields appeared to have a greater inhibiting effect on the oxygen-catalyzed than on the benzoyl peroxide – catalyzed reaction. Varying the frequency over the above range had no effect on the amount of inhibition caused by the field. At all temperatures, catalyst concentrations, voltages, and frequencies, the fields had no significant effect on the viscosity-average molecular weight of the polymer.

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