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Melting behavior of ethylene–tetrafluoroethylene alternating copolymer
Author(s) -
Pucciariello Rachele
Publication year - 1996
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19960222)59:8<1227::aid-app4>3.0.co;2-e
Subject(s) - etfe , tetrafluoroethylene , annealing (glass) , copolymer , melting point , materials science , differential scanning calorimetry , crystallite , enthalpy of fusion , crystallization , ethylene , melting temperature , thermal , polymer chemistry , thermodynamics , analytical chemistry (journal) , composite material , chemistry , organic chemistry , metallurgy , polymer , catalysis , physics , layer (electronics)
The melting behavior of the alternating copolymer of ethylene and tetrafluoroethylene (ETFE) was investigated by differential scanning calorimetry (DSC). A complex melting pattern is observed, strongly influenced by the thermal history. Three melting processes can be identified, whose heats of fusion and peak temperatures ( T m 1′ , T m 1 , and T m 2 at increasing values) strongly depend upon thermal treatments. The higher‐temperature melting peak T m 2 is not affected by the crystallization conditions (i.e., cooling rate and annealing); therefore, it can be attributed to more perfect crys+als present in the original sample. The peak at T m 1 increases when the cooling rate is decreased and upon prolonged and/or higher‐temperature annealing, and it fastly merges to the higher‐temperature peak at T m 2 . The peak at T m 1 can be due to crystals that are able to recrystallize and perfect during thermal treatments. Lastly, the peak at the lowest‐temperature T m 1′ , produced only by annealing and strongly developing on increasing annealing time and temperature, is the so‐called annealing peak that can be attributed to much poorer crystallites grown among the larger ones. The melting behavior of ETFE is compared with that of the ethylenechlorotrifluoroethylene (ECTFE) alternating copolymer. © 1996 John Wiley & Sons, Inc.