In the field of polymer processing, ‘reactive’ processing covers processes requiring a chemical reaction (e.g. polymerization, cross-linking, in situ filler generation, etc.). Today, environmental protection and ecodesign issues are moving towards the combination of ecologically virtuous processes, such as reactive extrusion, with natural polymers.
This project is part of this initiative to develop chemistry with milder conditions, by enhancing the properties of a biopolymer, chitosan, which can be found in shrimp exoskeletons, among others. Chitosan can be functionalized by grafting another polymer such as poly(caprolactone) to provide flexibility to final polymer-based materials to form biomedical films, for example. As part of a greener approach, grafting will be carried out by enzyme-catalyzed in situ polymerization, and will of course be free of toxic solvents. What’s more, the extrusion process allows an continous synthesis of higher quantities of polymer to be functionalized than in a batch reactor.
The objective of this PhD project is the synthesis and characterization of grafted chitosan from the polymerization of caprolactone using the process of extrusion assisted by enzymatic catalysis.
The scientific obstacles and challenges will be as follows:
- Carrying out the synthesis in an extruder and optimizing the process parameters, for example to limit degradation of the chitosan chains.
- Control the grafting points on chitosan according to the choice of the enzyme.
- Study grafting rate regarding the enzyme used.
- Evaluate the properties of materials obtained from functionalized polymers.
- Opening to others polysaccharides and grafted polyesters.