Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Entropy density, polymer glass formation

The lattice cluster theory (LCT) for glass formation in polymers focuses on the evaluation of the system s configurational entropy Sc T). Following Gibbs-DiMarzio theory [47, 60], Sc is defined in terms of the logarithm of the microcanonical ensemble (fixed N, V, and U) density of states 0( 7),... [Pg.143]

During the transformation of a monomer into a polymer, many atoms separated by van der Waals distances ( 5 A) participate in the formation of covalent bonds (1-3 A). Therefore during polymerization, an increase in the macroscopic density ensues, while on the molecular level a decrease in free volume and entropy occurs while the cooperativity of motions increase. Concomitantly the glass temperature can increase by more than 100 °C. Several important adhesive systems are based on this increase. The cyanoacrylate Super Glue starts as a monomer with a Tg <0 °C and it polymerizes to a linear soluble polymer with a Tg which is in the neighborhood of 100 °C upon appUcation under anaerobic conditions. For linear polymers the simple equation [74]... [Pg.192]


See other pages where Entropy density, polymer glass formation is mentioned: [Pg.139]    [Pg.208]    [Pg.175]    [Pg.178]    [Pg.182]    [Pg.112]    [Pg.2174]    [Pg.102]   
See also in sourсe #XX -- [ Pg.157 , Pg.158 , Pg.159 ]




SEARCH



Entropy density

Entropy glass

Formation entropy

Glass density

Glass formation

Polymer glass formation

Polymer glasses

© 2024 chempedia.info