Polymer studies sampling methods

Characterizing the Stereosequence Length of Propylene Oxide Polymers. The samples used in this study were the crystalline fractions of propylene oxide polymers made with various catalysts. Two methods were used to separate the fraction showing crystalline order (as judged from x-ray diffraction patterns) from the amorphous fraction ... 

FTIR is another surface-sensitive spectroscopic tool to analyze biomedical polymers since sample preparation is very simple for this technique. FTIR spectra should be recorded in reflection mode instead of transmission mode in order to analyze the functional groups present on polymer surfaces. ATR-FTIR has been apphed to study in vitro mineralization of porous starch scaffolds cultured in bone marrow stromal cells harvested from Wistar rats. Mineral deposition in in vitro cultures is usually followed by von Kossa stain or Alizarin red stain or by calcium uptake. These methods provide erroneous results because the scaffold matrix itself can take up some calcium from the medium. ATR-FTIR is devoid of the limitation and provides reliable information on the mineralization process. In the... 

Several polymer studies have been reported where the specimens were prepared by freeze fracture techniques. A modification of the freeze fracture method was used by Singleton et ah [432] in the preparation of plasticized PVC. The sample was notched, cooled and fractured and then immediately replicated with platinum-carbon. Replicas were stripped after warming to room temperature. The authors noted that the preparation was not highly reproducible, perhaps due to nonuniform cooling of large specimens. The results of such a study must be compared with other characterizations for accurate analysis. 

The development of modem FTIR spectrometers has been accompanied by a rapid evolution of many novel sampling techniques [31]. These include making routinely practicable some long-established methods such as diffuse reflectance, microscopy and specular reflectance, and the introduction of new procedures such as photoacoustic (PA) measurements. All of these have found extensive uses in polymer studies and characterisations [32]. For instance. 

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