Polyethylene oxide identification

Polyethylene oxide) (PEO) is a semicrystalline water-soluble polymer [64, 65], with a crystallinity that is very sensitive to the thermal history of the sample, making this property interesting as an indicator of degradation. Because it is biodegradable and biocompatible, PEO is a good candidate for environmental and medical applications [66-68]. The mechanisms of thermo- and photo-oxidation of PEO have already been investigated [69, 70] on the basis of IR identification of the oxidation products and are summarized in Scheme 10.1. 

The above-mentioned method is effective in identifying the molecules of detected ions. However, because PVDF film is not permeable to light, it is difficult to observe tissue sections. To resolve this problem, we developed a method to fix tissue sections on transparent film, and then performed MS on those sections.6 We used a conductive film because we expected the ionization efficiency would increase when the electric charge accumulation on the sample was reduced. The film used for this purpose was a polyethylene terephthalate (PET) film with a thickness of 75-125 pm, having a 5 15-nm-thick layer of evaporated oxidation indium tin (ITO) upon it (ITO film). This film is used in touch-panel displays because of its high transparency and superior conductivity. We used it to perform MS/MS for tissue sections and succeeded in identifying multiple proteins from mass spectra.6 Therefore, the further development of this method will enable the application of the mass-microscopic method to observe tissue by optical microscope and to perform tandem mass spectrometry (MSn) at the observation part, simultaneously, enabling the identification of molecules included the part. 

When testing for polyolefins with mercury(ll) oxide (see Section 6.2.1), in most cases, a yellow color develops more or less quickly. With blends of polyolefins, no significant color differentiation sufficient for identification occurs. However, if the polyethylene content of the blend is very high, no coloration, or only a slight coloration is seen because polyethylene does not react with mercury(ll) oxide. 

The identification of the a process as a c-shear relaxation and the p process as interlamellar shear in a drawn and annealed LDPE sheet was nicely confirmed by measurements of the anisotropy of dielectric relaxation [32], Pure polyethylene shows no dielectric response, so experiments were made on specimens that had been lightly decorated with dipoles by means of oxidation, to such a small extent that the overall relaxation behaviour was not significantly affected. The dielectric relaxation data showed marked anisotropy for the relaxation, consistent with its assignment to the c-shear relaxation, but the P relaxation... 

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