Degree of amorphousness

Humera, A. Buckton, G. Rawlins, D.A. The use of isothermal microcalorimetry in the study of small degrees of amorphous contend of hydrophobic powder. Int. J. Pharm. 1996,130, I95-20I. 

For more quantitative measurement. X-ray powder diffraction analysis is commonly used in industry (Hancock 1997 Jenkins 2000). A crystalline solid will typically show several distinct peaks which reflect the unique structure of crystals, whereas an amorphous solid will have no distinct peaks. This technique could be further used to assess quantitatively the degree of amorphism within a sohd, as mentioned in Example 12-5 (Connolly et al. 1996). In this case, it has been demonstrated that the shift of baseline of X-ray diffraction spectra is proportional to the degree of amorphism in the soUd phase (Crocker and McCauley 1995). 

A control of the properties is feasible not only by the chemical way via doping already mentioned in Sect. 2.2, but also by the degree of amorphicity and crystallinity, respectively, varying from absolutely amorphous layers over nanocrystals in an amorphous matrix to polycrystalline SiC layers [210-212], or by changing the C/Si ratio varying from a-Si H to a-C H [213, 214]. 

The higher the antimony content in the alloy, the higher the degree of hydration of the corrosion layer obtained, i.e. the volume of the gel zones in the lead dioxide layer increases due to incorporation of antimony ions in its structure. These results indicate that antimony increases the degree of amorphization of the PbOi layer, which is also confirmed by the XRD data for die anodic layer [34]. 

In Section 9.3.2 it was shown that amorphous nanoparticles of cellulose (ANP) have spherical to elliptical shapes with average diameters of 100 nm, high degree of amorphicity and increased content of sulfonic groups (Table 9.16). 

Incorporation of chlorine atoms onto the polyolefin backbone then causes sufficient molecular irregularity to break up crystalline chain segments of the base resin. As the chlorine content is increased, the crystallites gradually disappear and, eventually, the thermoplastic material becomes amorphous and behaves as an elastomer because of the inherent flexibility of the polyethylene chain. Chlorosulfonated polyethylene resins made in slurry or fluidized beds generally have a more blocky chlorine distribution, both intramolecularly and intermolecularly, so that the same degree of amorphous characteristic is not always achieved. The increase in molar cohesion, by the addition of chlorine atoms, increases the polymer solubility parameter, and thus decreases its miscibility with paraffinic and aromatic oils. So, as chlorine content of the polymer increases, resistance to swelling effect of oil increases. 

Luminescence under steady-state laser excitation with 780-785 nm revealed several narrow lines in IR range of the spectrum (Fig. 4.179). Natural monazite luminescence under cw laser excitations have been studied together with synthetic samples activated by different REE (Lenz et al. 2015). It was proved that the luminescence lines are mostly connected to trivalent REE such as Nd, Er, Pr, Sm. The broadening of the Stark sublevels correlates well with Th content and the degree of amorphization of the various monazite (Fig. 4.180). 

Fig. 4.180 Nd luminescence spectra in different natural monazite samples with different Th content and the degree of amorphization under cw excitation by 514 nm...

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