Molecular weight dependence of the physical properties of protonated polyaniline films and fibers

2001 ◽  
Author(s):  
Phillip N. Adams ◽  
Danielle Bowman ◽  
Lori Brown ◽  
Dali Yang ◽  
Benjamin R. Mattes
Keyword(s):  
Molecular Weight ◽  
Physical Properties ◽  
Molecular Weight Dependence ◽  
Polyaniline Films

Relation between Molecular Weights and Physical Properties of Rubber Fractions

1941 ◽  
Vol 14 (3) ◽  
pp. 580-589 ◽  
Author(s):  
G. Gee ◽  
L. R. G. Treloar
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Elastic Properties ◽  
Elastic Material ◽  
Experimental Results ◽  
Molecular Weights ◽  
High Elasticity ◽  
Latex Rubber

Abstract As high elasticity is a property possessed only by substances of high molecular weight, it is of interest to enquire into the relation between the elastic properties of a highly elastic material such as rubber and its molecular weight. An investigation on these lines has been made possible through the work of Bloomfield and Farmer, who have succeeded in separating natural rubber into fractions having different average molecular weights. The more important physical properties of these fractions have been examined with the object of determining which of the properties are dependent on molecular weight and which are not. Fairly extensive observations were made on the fractions from latex rubber referred to as Nos. 2, 3 and 4 by Bloomfield and Farmer, and some less extensive observations were carried out on the less oxygenated portion of fraction No. 1 obtained from crepe rubber (called hereafter 1b) . Before considering these experimental results, and their relation to the molecular weights of the fractions, it will be necessary to refer briefly to the methods used for the molecular-weight determinations, and to discuss the significance of the figures obtained.

Chemical synthesis of poly(β-hydroxybutyrate) by the polymerization of (R,S)-β-butyrolactone with aluminoxane catalysts

1995 ◽  
Vol 41 (13) ◽  
pp. 274-281 ◽  
Author(s):  
Robert W. Lenz ◽  
John Yang ◽  
Bin Wu ◽  
C. Jeff Harlan ◽  
Andrew R. Barron
Keyword(s):  
Molecular Weight ◽  
Chemical Synthesis ◽  
Physical Properties ◽  
High Molecular Weight ◽  
Crystalline Polymers ◽  
Group 4 ◽  
Catalyst Systems

Racemic β-butyrolactone can be polymerized to crystalline polymers of reasonably high molecular weight by the use of aluminoxane catalysts. Investigations in this and other laboratories have shown that these polymers can be fairly highly isotactic, and in that form they are closely related in structure and physical properties to a reserve polyester produced by many bacteria: poly(β-hydroxybutyrate). In the present investigation, Ziegler–Natta type aluminoxane catalyst systems and a new aluminoxane derivative, tert-butylaluminoxane, were evaluated in attempts to polymerize racemic β-butyrolactone in higher yields to polymers of higher molecular weight and higher stereoregularity. The addition of group 4 metallocenes as cocatalysts for both methylaluminoxane and iso-butylaluminoxane catalysts gave higher yields of the isotactic polymer than those obtained with these catalysts alone, but surprisingly, the tert-butylaluminoxane catalysts produced predominantly syndiotactic rather than isotactic polymers.Key words: poly(β-hydroxybutyrate), β-butyrolactone, aluminoxane catalysts, isotactic poly(β-hydroxybutyrate), syndiotactic poly(β-hydroxybutyrate).

Molecular weight dependence of the conformational phase transition and electroluminescence of diarylpolysilane diodes

2000 ◽  
Vol 88 (6) ◽  
pp. 3408-3413 ◽  
Author(s):  
Satoshi Hoshino ◽  
Kazuaki Furukawa ◽  
Keisuke Ebata ◽  
Ingo Breyl ◽  
Hiroyuki Suzuki
Keyword(s):  
Phase Transition ◽  
Molecular Weight ◽  
Molecular Weight Dependence

Composition and molecular-weight dependence of the glass transition in polystyrene-poly(2,6-dimethylphenylene ether) blends

Polymer ◽  
1988 ◽  
Vol 29 (12) ◽  
pp. 2235-2243 ◽  
Author(s):  
Marco Aurelio de Araujo ◽  
Reimund Stadler ◽  
Hans-Joachim Cantow
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Molecular Weight Dependence
Sign in / Sign up

Export Citation Format

Share Document