Print: | ISSN 0256-1115 |
Online: | ISSN 1975-7220 |
Korean Journal of Chemical Engineering,
Vol.27, No.2, 524-530, 2010 Comparison of thermal properties of crude by-product polyolefin wax, fractionated paraffin wax and their blend
The molecular weight and thermal properties of unfractionated by-product polyolefin wax (wax K) from a naphtha cracking unit, fractionated commercial paraffin wax (wax J) and their blend (wax M) were evaluated and were compared with each other using differential scanning calorimetry (DSC), normal and high-temperature gel permeation chromatography (GPC), and wide-angle X-ray diffraction (WAXD). Such properties as molecular weight distribution, melting temperature and degree of crystallization were altered by blending wax K with wax J. By blending with two parts of wax K and one part of wax J to prepare wax M, Mw of wax K was shifted, by half, to that of wax J in order to approach that of wax M, whereas the Mn of wax K remains almost unaltered to become that of wax M. In particular the effect of blending of wax K and wax J turned out co-crystallization for the sharper lower-melting-temperature endothermic peak of the blend, indicating narrower molecular distribution, than that of wax K at the melting temperature shifted even below that of wax J. The total degree of crystallinity for the blend, wax M, turns out less than that before blending wax K with wax J, which may be attributed to the effect of co-crystallization due to blending.
Keywords:
Crude By-product Polyolefin Wax; Commercial Paraffin Wax; Blend; Molecular Weight Distribution; Melting-temperature Shift; Degree of Crystallization; Co-crystallization
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