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On the relationship between microhardness and glass transition temperature of some amorphous polymers

✍ Scribed by S. Fakirov; F. J. Baltá Calleja; M. Krumova

Publisher
John Wiley and Sons
Year
1999
Tongue
English
Weight
115 KB
Volume
37
Category
Article
ISSN
0887-6266

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✦ Synopsis

On the basis of microhardness (H) data measured at room temperature only for a number of polymers in the glassy state, a linear correlation between H and the glass transition temperature T g has been found (H ϭ 1.97T g Ϫ 571). By means of this relationship, the deviation of the H values from the additivity law for some multicomponent and/or multiphase polymeric systems can be accounted for. The latter usually contains a liquidlike soft component and/or phase with T g below room temperature. A completely different deformation mechanism in comparison to systems with T g above room temperature is invoked. A novel expression for the hardness of polymers in terms of crystallinity of the single components and/or phases, the T g values, and the mass fraction of each component is proposed. This expression permits the calculation of (i) the room-temperature H value of amorphous polymers, mainly containing single bonds in the main chain, provided T g is known, and of (ii) the contribution of the soft liquidlike components (phases) to the hardness of the entire multiphase system.

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