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Crystal structures and voids in diesel waxes
Author(s) -
Gerson A. R.,
Nyburg S. C.,
McAleer A.
Publication year - 1999
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889898012801
Subject(s) - isostructural , orthorhombic crystal system , wax , crystallography , materials science , void (composites) , crystal (programming language) , diffraction , space group , crystal structure , x ray crystallography , chemistry , physics , composite material , optics , computer science , programming language
Diesel waxes containing n ‐alkanes in the range n 9–30 show only two types of X‐ray diffraction pattern. When indexed these are seen to belong to the orthorhombic space groups Bb 2 1 m and Fmmm ; they are isostructural with two binary phases, one phase having n 24 and 26 and the other n 22 and 24. We designate these the low‐disorder (LD) and high‐disorder (HD) phases, respectively. From the long spacings shown in the XRD patterns, it is possible to calculate the percentage of void space present in the wax crystals. It is found that the larger the spread of n values in the wax composition ( i.e. the larger the variance in chain length), the greater the tendency to crystallize in the HD form and the more extensive the voids.