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On the conformational behavior and solid‐state extrudability of crystalline polymers
Author(s) -
Aharoni S. M.,
Sibilia J. P.
Publication year - 1979
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760190615
Subject(s) - extrusion , polymer , materials science , crystallinity , solid state , melting point , relaxation (psychology) , atmospheric temperature range , crystallography , thermodynamics , composite material , chemistry , psychology , social psychology , physics
Extrusion experiments on thirteen polymers in our laboratory and extrusion and forging studies on nine polymers in other laboratories reveal that solid‐state extrusion and malleability occur in semi‐crystalline polymers that have a crystalline relaxation, α c at the temperature T α c , and do not occur in semicrystalline polymers devoid of α c . The solid‐state extrusion takes place in the temperature range of T α c ≤ T < T m with T m being the melting point. In this temperature, range, the polymeric crystals show a measure of disorder, observed by several techniques and by small heats and entropies of fusion. A survey of the literature indicates that, in general, polymers which have a α c and are solid‐state extrudable have shallow and broad bottoms to the energy‐wells describing their most stable crystalline conformations, and polymers showing no α c have steep‐walled energy‐wells for the same conformations.