Development of a Biodegradable/Ecofriendly Turbine Lubricant from a Novel Polyalkylene Glycol Ester
Tóm tắt
A biodegradable/ecofriendly polyalkylene glycol ester 1,2-PTHC6 (polyglycol containing 1:2 mol fraction of propylene oxide (PO) and tetrahydrofuran (THF)) esterified with n-hexanoic acid (C6 fatty acid) was synthesized following the two step reaction. At first, propylene oxide and tetrahydrofuran were polymerized in 1, 2-dichloroethane to obtain a polymer 1,2-PTH (polyglycol containing 1:2 mol fraction of PO and THF) with molecular weight (
$$\overline{{{\text{M}}_{{\text{n}}} }}$$
) 838.6. In the second step, esterification of 1,2-PTH was done with C6 fatty acid catalyzed by p-toluenesulfonic acid and toluene as solvent to obtain final product 1,2-PTHC6 having the molecular weight (
$$\overline{{{\text{M}}_{{\text{n}}} }}$$
) 982.7. The crystallinity and molecular structure of the synthesized poly(propyleneoxide-co-tetrahydrofuran) ester was studied by FT-IR, X-ray diffraction and DSC. The physicochemical properties like; pour point (ASTM 97), kinematic viscosity (ASTM 445), viscosity index (ASTM 2270), refractive index, density, thermal stability, autoignition temperature (IS 7895), corrosion stability and oxidation stability (IP 48) were evaluated. The extreme pressure (IP 239) and antiwear properties (ASTM D 4172) were also evaluated in terms of weld load and average wear scar diameter respectively. All the properties so determined were compared with the specifications of lube oils and it was revealed that this poly(propyleneoxide-co-tetrahydrofuran) ester i.e. 1,2-PTHC6 had suitable physical and tribological properties to be used as base stock for turbine lubricant.
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