Study on the rheological and tribological behavior of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) environmentally friendly lubricating grease formulated with biobased ester oil

Biobased lubricants have garnered significant attention due to their environmentally friendly characteristics. In this study, poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB) was employed as a thickener to successfully prepare four biobased greases with identical NLGI consistency grades. Scanning electron microscopy (SEM) characterization revealed that the P34HB thickener formed a three-dimensional lamellar network microstructure, elucidating the grease formation mechanism of the P34HB thickener. Rheological tests demonstrated that this grease system exhibited typical non-Newtonian fluid behavior and pronounced shear-thinning effects. Tribological performance evaluation indicated that the grease formulated with acetyl triethyl citrate (ATEC) as base oil displayed optimal friction-reducing and anti-wear properties. This research provided expanded base oil options for developing eco-friendly lubricants, extended the application scope of biobased materials in grease technology, and held substantial engineering value for promoting innovative development in green lubrication technologies