Transition measurements using differential thermal analysis techniques

Abstract

A system for the study of polymer structure by differential thermal analysis (DTA) techniques is presented. The need for an inert reference body has been eliminated by the use of a thermal delay within the sample itself. Typical data showing both first‐ and second‐order transition behavior for appropriate polymers are presented. The applicability of the technique to liquids is also shown. Three first‐order transitions have been found in trans‐1,4‐polybutadiene. The insoluble nature of high polymers in one another is again confirmed, even in those systems which disperse well. The latent heat of crystallization of cis‐1,4‐polybutadiene is about 2.1 kcal./mole.

Structure of Polybutadienes Synthesized with a New Catalyst System, 2. Blends oftrans-andcis-1,4-Polybutadiene

“…[12] This indicates that most of the 1,2-units are distributed within the amorphous part of trans-1,4-PB. In addition, according to literature, [13,14] the presence of statistically distributed units in copolymers should lead to a decreasing transition temperature with increasing amount of those units, whereas, from the data of Table 2, one can see that for all the prepared samples the reverse situation seems to be true.…”

Quarterly report for December 1, 1961 to March 1, 1962 on elastomeric seals and materials at cryogenic temperatures

“…If curve 2 is taken as the additive expansion of the pure polymer and 16. 5% (20 parts) magnesium oxide, the overall contraction from 300°K…”

The use of differential scanning calorimetry for the evaluation of dental materials

“…and to relate these to the dimensional stability of the materials concerned. The method has been used to study transition temperatures in other polymer systems by Lambert (1969) and Dannis (1973).…”