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Investigation of melting behaviors and crystallinity of linear polyamide with high‐aliphatic content
Author(s) -
Kaya Ethem,
Mathias Lon J.
Publication year - 2011
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/app.34534
Subject(s) - crystallinity , differential scanning calorimetry , triclinic crystal system , polyamide , materials science , annealing (glass) , crystallization , recrystallization (geology) , melting point , crystallography , nylon 66 , nylon 6 , polymer chemistry , analytical chemistry (journal) , crystal structure , polymer , chemistry , composite material , thermodynamics , chromatography , organic chemistry , paleontology , physics , biology
Abstract The melting behaviors and crystal structures of a long alkyl chain polyamide and nylon 18 18, were investigated under annealing and isothermal crystallization conditions. Nylon 18 18 showed multiple melting peaks in differential scanning calorimetry (DSC) thermograms depending on thermal history of the samples. The origin of the multiple melting peaks may be a result of a melting and recrystallization mechanism during DSC scans. Wide‐angle X‐ray diffraction patterns showed two new diffraction peaks, which appeared at 0.44 and 0.37 nm, and are characteristic peaks of α‐form (triclinic structure) of even–even nylons with increasing annealing temperature. The intensities of these peaks increased, and they split further apart, with elevated annealing temperatures. The solid‐state 15 N CP/MAS NMR spectra of the nylon 18 18 samples that had been quenched and annealed also confirmed the α‐crystalline form. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011