Extraction of Biolubricant via Chemical Recycling of Thermosetting Polymers

Abstract

Dicarboxylic acid esters possessing the consistency of conventional hydrocarbon oils have been utilized as biolubricants and additives. In general, dicarboxylic acid ester biolubricants are obtained by catalytic transesterification between fatty acids, methyl esters, or triglycerides as precursors. Here, we develop a new strategy to produce dicarboxylic acid esters through the chemical recycling of thermosetting polymer waste. Thermosets with tunable mechanical properties derived from epoxy oligomer and dicarboxyl acid can be decomposed in a zinc acetylacetonate/2-ethyl-hexanol solution at relatively mild temperatures (<170 °C) and ordinary pressure. The epoxy dissolution rate can be enhanced by increasing the temperature and catalyst loading. The depolymerized epoxy oligomer of dicarboxylic acid ester was obtained as a biolubricant. In addition, the catalyst can be facilely reclaimed and reused. This work presents a new approach in engineering polymer waste to generate eco-friendly high-value oil, such as biolubricant, which is beneficial to reduce environmental pollution and alleviate petrochemical source consumption.

Efficient and sustainable recovery of lipids from sewage sludge using ethyl esters of volatile fatty acids as sustainable extracting solvent

“…In Europe alone, according to European Commission resources, 5.7 Mt yr -1 of lubricants are used and, a significant part is actually recovered and recycled: only around 1.5 Mt year -1 needs to be replaced and manufactured since lost, half of which (0.7 Mt) in an uncontrolled way [45]. Under these conditions the replacement of fossil oils with bioderived (from exhausted feedstocks) and biodegradable lubricants might significantly mitigate the environmental impact due to this dispersion [46]. At the Aguascalientes wastewater treatment plant, sewage produced by 800,000 People Equivalent is typically treated and around 20,000 t of dry solids per year of primary sludge are produced.…”

Multicycling of Epoxy Thermoset Through a Two‐Step Strategy of Alcoholysis and Hydrolysis using a Self‐Separating Catalysis System

“…The chemical recovery of anhydride‐cured epoxy thermosets typically included organic solvolysis and hydrolysis [28–40] . Due to the lipophilic wettability of epoxy thermosets, it is more efficient to perform degradation in organic solvents, mostly alcohols, with the assistance of catalysts, such as zinc acetate, 1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene (TBD), and others [33–38] .…”

“…The chemical recovery of anhydride‐cured epoxy thermosets typically included organic solvolysis and hydrolysis [28–40] . Due to the lipophilic wettability of epoxy thermosets, it is more efficient to perform degradation in organic solvents, mostly alcohols, with the assistance of catalysts, such as zinc acetate, 1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene (TBD), and others [33–38] . However, the degradation products still contain ester groups after alcoholysis, and consequently cannot be applicable to new epoxy materials but only other fields such as lubricating oil.…”

“…Another thorny issue is that the use of high‐boiling solvents (ethylene glycol (EG), polyethylene glycol(PEG), N‐methylpyrrolidone (NMP), etc. ), which was meant to reduce the reaction pressure, negatively impacts the subsequent product separation and reuse [33–39] . We recently have developed a method for efficient and complete degradation of anhydride‐cured epoxy resins by diethylenetriamine (DETA) [40] .…”

Novel Unsaturated Polyester Nanocomposites via Hybrid 3D POSS-Modified Graphene Oxide Reinforcement: Electro-Technical Application Perspective

“…The current revolution in polymer technologies reflects the role of thermosetting plastics in their advancement. The dexterous properties of the thermosetting plastics have empowered researchers to widen their possible application in a vast range of fields [1][2][3][4]. The enticing properties such as low viscosity (uncured state), customized modulus (according to application), high thermal stability, smooth process ability and their ability to use with fillers has provided impetus in expanding their commercial applications [5].…”