Polyethylene waxes synthesis

While the extracts of SPMDs are generally less difficult to purify than are extracts of tissue or sediment, certain interferences can be problematic for some types of analyses. The most important of these potential interferences are codialyzed polyethylene oligomers (i.e., the so-called polyethylene waxes), oleic acid, and methyl oleate. The latter two interferences are residual from the synthesis of the triolein. Also, oxidation products of triolein may be present in dialysates of SPMDs that have been exposed (especially in the presence of light) to air for periods exceeding 30 d. For a standard 1-mL triolein SPMD, the mass of all these interferences in dialysates is generally <30 mg or about 6 mg g of SPMD (Huckins et al., 1996). Another potential interference is elemental sulfur, which is often present in sediment pore water and is concentrated by SPMDs. However, both polyethylene waxes and elemental sulfur are readily removed using the previously described SEC procedure. 

Cataldo, F. Synthesis of polyynes (and ene-ynes) segments by dechlorination reactions of chlorinated polyethylene wax and chlorinated docosane. J. Mater. Sci. 2000, 55(10), 2413-2419. 

Table 1. Synthesis of Calcium-Containing Polyethylene Waxes...

WAXS indicated the possible full exfoliation of the montmorillonite in the polyethylene. No TEM pictures were provided. The tensile strength of the polyethylene increased from approximately 29.8 MPa for the pure polymer to approximately 33.6 MPa for a 2.8 wt. % montmorillonite content in the polyethylene. The disadvantage of this approach is the necessity to utilize solvents for the polyethylene-montmorillonite synthesis. 

Synthetic waxes consist of Fischer-Tropsch, polyethylene, and specialty waxes. Fischer-Tropsch waxes are produced from synthesis gas (CO and H2). They are often termed synthetic paraffin . Crystallinity is similar to paraffin, but with a higher and bimodal melting point (see Figs. 11 and 12). F-T waxes are used instead of paraffin where higher heat resistance is needed. 

Fischer-Tropsch (FT) technology converts synthesis gas produced by reforming of methane or coal gasification into waxy products. Long alkanes (-CH2 -chains) produced by using FT synthesis are chemically similar to polyethylene. Lubricating oils derived from isomerization of FT waxes are gaining interest due to increased demand for lubricants with the advanced performance and environmental benefits described earlier. 

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