Amorphous state differential scanning calorimetry

Differential scanning calorimetry has been utilized by many to investigate inclusion complexes in solid-state. The melting endotherm of the substrate typically is changed as a result of complexation. The complex formed may have a different melting point, or no melting endotherm because of its amorphous nature. The physical mixture in most cases will still exhibit the melting endotherms of the substrate and the CD (if it is crystalline). 

Various methods have been employed to find out about the structure of polymer electrolytes. These include thermal methods such as differential scanning calorimetry (DSC), differential thermal analysis (DTA), X-ray methods such as X-ray diffraction and X-ray absorption fine structure (XAFS), solid state NMR methods particularlyusing7LiNMR,andvibrationalspectroscopicmethodssuch as infrared and Raman [27]. The objective of these various studies is to establish the structural identity of the polymer electrolyte at the macroscopic as well as the molecular levels. Thus the points of interest are the crystallinity or the amorphous nature of materials, the glass transition temperatures, the nature and extent of interaction between the added metal ion and the polymer, the formation of ion pairs etc. Ultimately the objective is to understand how the structure (macroscopic and molecular) of the polymer electrolyte is related to its behavior particularly in terms of ionic conductivity. Most of the studies have been carried out, quite understandably, on PEO-metal salt complexes. In comparison, there has been no attention on the structural aspects of the other polymers particularly at the molecular level. 

The structure of lignin consists of phenylpropane units forming a three dimensional polymer network which have not an ordered and regular super-macromolecular structure. The X-ray dififractometry and differential scanning calorimetry (DSC) indicated that the isolated lignins in the solid state are amorphous polymers. 

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