Temperature-modulated calorimetry of hexacontane and oligomer fractions of poly(oxyethylene) and poly(oxytetramethylene)

被引：17

作者：

Pak, J ^{[1
]}

Pyda, M

Wunderlich, B

机构：

[1] Univ Tennessee, Dept Chem, Knoxville, TN 37996 USA

[2] Oak Ridge Natl Lab, Div Chem & Analyt Sci, Oak Ridge, TN 37831 USA

来源：

THERMOCHIMICA ACTA | 2003年 / 396卷 / 1-2期

关键词：

supercooling; melting; crystallization; quasi-isothermal TMDSC; oligo(oxyethylene); oligo(oxytetramethylene); paraffin; hexacontane; polyethylene; DSC;

D O I：

10.1016/S0040-6031(02)00515-4

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

The paraffin hexacontane, C60H122, and oligomeric fractions of poly(oxyethylene), POE, and poly(oxytetramethylene), POTM, of varying low molar masses were studied with temperature-modulated calorimetry. The analyses were by standard differential scanning calorimetry (DSC) and quasi-isothermal, temperature-modulated DSC, TMDSC. Small sample masses were examined with temperature amplitudes from 0.05 to 2.5 K, using periods of 60 s. The supercooling decreases with molar mass for all three types of samples. The melting varied between fully irreversible, reversing, and largely reversible. There are no major differences in supercooling between extended- and folded-chain crystals. Due to conformational contributions, all crystals increase their heat capacities within the melting range from the level set by the vibrational spectrum to that of the liquid. Published by Elsevier Science B.V.

引用

页码：43 / 56

页数：14

共 39 条

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