Lignin from Hardwood and Softwood Biomass as a Lubricating Additive to Ethylene Glycol
Liwen Mu,
Jian Wu,
Leonidas Matsakas,
Minjiao Chen,
Alireza Vahidi,
Mattias Grahn,
Ulrika Rova,
Paul Christakopoulos,
Jiahua Zhu,
Yijun Shi
Affiliations
Liwen Mu
Division of Machine Elements, Luleå University of Technology, 97187 Luleå, Sweden
Jian Wu
Division of Machine Elements, Luleå University of Technology, 97187 Luleå, Sweden
Leonidas Matsakas
Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 97187 Luleå, Sweden
Minjiao Chen
Division of Machine Elements, Luleå University of Technology, 97187 Luleå, Sweden
Alireza Vahidi
Division of Machine Elements, Luleå University of Technology, 97187 Luleå, Sweden
Mattias Grahn
Chemical Technology, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 97187 Luleå, Sweden
Ulrika Rova
Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 97187 Luleå, Sweden
Paul Christakopoulos
Biochemical Process Engineering, Division of Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, 97187 Luleå, Sweden
Jiahua Zhu
Intelligent Composites Laboratory, Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325, USA
Yijun Shi
Division of Machine Elements, Luleå University of Technology, 97187 Luleå, Sweden
Ethylene glycol (EG)-based lubricant was prepared with dissolved organosolv lignin from birch wood (BL) and softwood (SL) biomass. The effects of different lignin types on the rheological, thermal, and tribological properties of the lignin/EG lubricants were comprehensively investigated by various characterization techniques. Dissolving organosolv lignin in EG results in outstanding lubricating properties. Specifically, the wear volume of the disc by EG-44BL is only 8.9% of that lubricated by pure EG. The enhanced anti-wear property of the EG/lignin system could be attributed to the formation of a robust lubrication film and the strong adhesion of the lubricant on the contacting metal surface due to the presence of a dense hydrogen bonding (H-bonding) network. The lubricating performance of EG-BL outperforms EG-SL, which could be attributed to the denser H-bonding sites in BL and its broader molecular weight distribution. The disc wear loss of EG-44BL is only 45.7% of that lubricated by EG-44SL. Overall, H-bonding is the major contributor to the different tribological properties of BL and SL in EG-based lubricants.
