Calorimetry: fundamentals, instrumentation and applications

Clearly divided into three parts, this practical book begins by dealing with all fundamental aspects of calorimetry. The second part looks at the equipment used and new developments. The third and final section provides measurement guidelines in order to obtain the best results. The result is optimized knowledge for users of this technique, supplemented with practical tips and tricks

Hydrogenated butadiene/ethene/1-olefin terpolymers as model substances for short-chain branched polyethylene

Poly[(butadiene-alt-ethene)-co-(butadiene-alt-1-olefin)] terpolymers were synthesized by Ziegler-Natta polymerization using VO(O-neopentyl)2Cl/Al(i-Bu)3 catalyst system in toluene. Variation of the 1-olefin/ethene ratio in the monomer feed produces terpolymers with mixed units of butadiene-alt-ethene and butadiene-alt-1-olefin. After hydrogenation one obtains model substances for LLDPE with a special distribution of methylene sequences between branching points. Differential scanning calorimetry (DSC) was used to determine the degree of crystallinity and the melting behavior. From the melting temperature region, the thickness distribution of the crystal lamellac, and thus the average number of C-atoms between the alkyl branches, can be determined. From detailed X-ray diffractometry, the mean crystallite size, the lattice distortions and the degree of crystallinity was determined for those products which show distinct reflections. The crystallization behavior can only be described by a three-phase model

A method to quantify crystallinity in amorphous metal alloys: A differential scanning calorimetry study.

We developed and describe a differential scanning calorimetry method for calculating the initial crystallinity, change of crystallinity and crystallinity percentage of amorphous metal alloys as a function of temperature. Using thermodynamic enthalpies of amorphous, crystalline and partially devitrified specimens, our methodology is capable of determining crystallinity percentages as low as a few percent. Moreover, the linear relationship between the set (pre-determined) and calculated crystallinities of experimental samples indicates that there is no need to prepare calibration samples before measuring the crystallinity percentage of target samples. This technique also eliminates the need for expensive in situ accessories, such as those required in electron microscopy. Thus, the technique is highly relevant as a primary technique for characterization of devitrification behavior in amorphous materials