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Relaxation processes at the glass transition in polyamide 11: From rigidity to viscoelasticity

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National Technical University of Athens   

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Digital Library of National Technical University of Athens | Dspace@NTUA   

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Relaxation processes at the glass transition in polyamide 11: From rigidity to viscoelasticity (EN)
Gerhard-Multhaupt, R (EN)
Frubing, P (EN)
Spanoudaki, A (EN)
Kremmer, A (EN)
Pissis, P (EN)
journalArticle (EN)
2014-03-01T01:25:04Z
2006 (EN)
Relaxation processes associated with the glass transition in nonferroelectric and ferroelectric polyamide (PA) 11 are investigated by means of differential scanning calorimetry, dynamic mechanical analysis, and dielectric relaxation spectroscopy (DRS) in order to obtain information about the molecular mobility within the amorphous phase. In particular, the effects of melt quenching, cold drawing, and annealing just below the melting region are studied with respect to potential possibilities and limitations for improving the piezoelectric and pyroelectric properties of PA 11. A relaxation map is obtained from DRS that shows especially the crossover region where the cooperative alpha relaxation and the local beta relaxation merge into a single high-temperature process. No fundamental difference between quenched, cold-drawn, and annealed films is found, though in the cold-drawn (ferroelectric) film the alpha relaxation is suppressed and slowed down, but it is at least partly recovered by subsequent annealing. It is concluded that there exists an amorphous phase in all structures, even in the cold-drawn film. The amorphous phase can be more rigid or more viscoelastic depending on preparation. Cold drawing not only leads to crystallization in a ferroelectric form but also to higher rigidity of the remaining amorphous phase. Annealing just below the melting region after cold drawing causes a stronger phase separation between the crystalline phase and a more viscoelastic amorphous phase. (c) 2006 American Institute of Physics. (EN)
Physics, Atomic, Molecular & Chemical (EN)
Annealing (EN)
Dielectric relaxation spectroscopy (DRS) (EN)
Molecular mobility (EN)
Polyamides (EN)
Crystallization (EN)
Mechanical properties (EN)
Cold drawing (EN)
Spectroscopic analysis (EN)
Rigidity (EN)
Amorphous phase (EN)
Dielectric relaxation (EN)
Quenching (EN)
Journal of Chemical Physics (EN)
Αγγλική γλώσσα
AMER INST PHYSICS (EN)
National Technical University of Athens
Digital Library of National Technical University of Athens | Dspace@NTUA
Κεντρική Βιβλιοθήκη Ε.Μ.Π.
Ιδρυματικό Αποθετήριο
Δημοσιεύσεις μελών Δ.Ε.Π. σε περιοδικά



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