Polymers are produced on an enormous scale globally and the majority of plastic waste is either incinerated - generating toxic substances - or placed in landfill sites where it can take many decades to decompose. It is estimated that 22% of the total volume of all landfill sites are occupied by waste plastics. In the United Kingdom over 100kg per person of plastic packaging waste is generated each year; this offers a potential stream of raw material that is currently not reused or recycled.
In this work the synthesis of lubricant additives from waste commodity polymers is described. A degradation method using an adapted microwave reactor and selected reagents allows for the degradation of commodity polymers; polystyrene and polyethylene into terminal double bond olefin oligomers. A variety of Novel block copolymer dispersant viscosity modifiers were synthesised from polystyrene, maleic anhydride, stearyl methacrylate and various N-maleimides using Reversible Addition Chain Transfer-fragmentation (RAFT) Polymerisation. Degraded polystyrene was incorporated into the synthesis of the novel dispersant viscosity modifiers. An analytical method involving offline and online 1H and 13C NMR and FTIR spectroscopy was used to characterise the degraded polystyrene and its incorporation into the dispersant viscosity modifier along with GPC, GC-MS and MALDI-MS. The reaction kinetics at the beginning of the RAFT polymerisation of styrene and maleic anhydride was also studied and lead to the development of a method to control the placement of alternating blocks of styrene-alt-maleic anhydride within a polymer backbone, offering the potential to afford complex macromolecular architectures in one pot synthesis reactions. Finally, the novel dispersants and other potential lubricant additive synthesis products were subjected to viscometric, rheological and thermal testing by formulation into a Heavy Duty engine oil formulation.
Gregory J. Hunt, Durham 201
