RAFT Emulsion Polymerizations using Biomass-Derived Isosorbide Monomers

Fossil feedstocks are a finite resource leading to diminished availability of derived petrochemicals, which together with environmental concerns are driving a change to renewable biomass as a source of chemicals and plastics. Isosorbide is a robust chemical scaffold sourced from lignocellulosic biomass, which has been incorporated into a wide range of commercial step-growth polymers, including thermoset plastics and high-performance materials. Greater synthetic diversity is however achieved by selective functionalization of the isosorbide scaffold, as established by Prof. Aldabbagh with a protection-deprotection strategy. A diverse range of isosorbide monomers containing a polymerizable methacrylate appendage have now been prepared and reported to undergo radical addition polymerization. The purpose of this overseas travel grant to the UNSW Sydney is to carry out reversible addition-fragmentation chain transfer (RAFT), as a water-based emulsion polymerization. RAFT emulsion polymerizations yield core-shell nanoparticles (NPs) in water consisting of a hydrophobic polymer block core and hydrophilic polymer block shell. Core-shell NP forming heterogeneous polymerizations have not previously been investigated for isosorbide monomers. Prof. Zetterlund of the UNSW Sydney is a world leader in emulsion polymerization. He has used RAFT emulsion polymerization for the rapid and precision syntheses of multiblock copolymers, including of monomers, like methacrylates that are known to polymerize slowly. The objective of this two-month visit, is a two-way knowledge exchange, with Prof Aldabbagh introducing a new monomer family (isosorbide) for RAFT emulsion polymerization, and Prof. Zetterlund providing training in water-based latex and film formation, as well as state-of-the-art NP characterization techniques. The challenge this project addresses is the synthesis of core-shell NPs consisting of isosorbide with the aim of conversion of this poly(isosorbide) latex into a unique continuous material film. Film formation provides potential applications for naturally sourced and low toxicity poly(isosorbides) as waterproof coatings against metal corrosion or to improve biocompatibility of medical devices. RAFT emulsion polymerization provides endless opportunities in fine-tuning the properties of these advanced materials through altering the order and length of blocks. Monomer functionalization allows inclusion of specific functional groups on the isosorbide scaffold that can impact self-assembly and polymer properties. Herein, this environmentally friendly and industrially scalable water-based polymerization will provide more sustainable materials with potential to facilitate technological advances. The project is highly synergistic with the research agenda of the project leader’s institution, Kingston University that recently launched the Knowledge Exchange & Research Institute (KERI), which aims to increase commercialization initiatives, including through high value collaborations. This visit is expected to be fruitful given the track record of this collaboration, and the research-intensive environment at the UNSW Sydney, which is one of the world’s top 20 Universities.