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High‐pressure differential thermal analysis of polymers
Author(s) -
Kojima Yoshitsugu,
Takahara Minoru,
Matsuoka Takaaki,
Takahashi Hideroh
Publication year - 2001
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.1188
Subject(s) - enthalpy of fusion , differential thermal analysis , melting point , materials science , enthalpy , volume (thermodynamics) , polymer , thermodynamics , nylon 6 , fusion , polymer chemistry , atmospheric pressure , thermal analysis , analytical chemistry (journal) , chemistry , thermal , composite material , organic chemistry , oceanography , linguistics , philosophy , physics , diffraction , optics , geology
Melting behavior under high pressure of nylon 6, nylon 6‐clay hybrid (NCH) and poly(butylene terephthalate) was investigated by high‐pressure differential thermal analysis (DTA). It was found that the melting temperature and the pressure dependency of the melting temperature of NCH were low compared with those of nylon 6. Using the melting temperature, the pressure dependency of the melting temperature, and the heat of fusion (the enthalpy of fusion), the Clausius‐Clapeyron equation was used to determine the volume changes on melting of the polymers at atmospheric pressure Δ V m 0 (DTA). Δ V m 0 (DTA) of NCH was lower than that of the nylon 6 α‐form. The smaller Δ V m 0 (DTA) of NCH was attributed to the presence of nylon 6 γ‐form in NCH. The values of Δ V m 0 (DTA) for nylon 6 and poly(butylene terephthalate) were similar to those obtained from pressure‐volume‐temperature relationships Δ V m 0 (PVT) of those polymers. The entropies of fusion were constant and independent of pressures up to 100 MPa. The volume changes on melting (Δ V m in cm 3 /g) under high pressure can be approximately described by the following equation: Δ V m = 0.165 T m V w ( dT m / dP )/( dT m 0 / dP )/298, where T m and T m 0 are the melting temperatures (in K) under high pressure and atmospheric pressure, respectively and V w is the van der Waals volume of the polymer (cm 3 /g). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1046–1051, 2001