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Free volume entropy, polymer glass formation

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 Free volume entropy, polymer glass formation is mentioned: [Pg.137]    [Pg.201]    [Pg.178]    [Pg.90]    [Pg.76]   
See also in sourсe #XX -- [ Pg.175 , Pg.176 , Pg.177 ]




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