Metal-containing catalysts will be replaced by organic catalysts, which have been shown to control the polymerisation of lactide, but their activity must be improved to meet industrial standards.
InnoREX consortium hopes to achieve this by low-intensity but highly-targeted application of alternative energies, such as microwaves, ultrasound and laser light.
These energies increase catalyst activity and enable precise control of the reaction by exciting only small parts of the reaction mixture without response time.
Metal-free polymerisation of PLA
InnoREX will develop a novel reactor concept using alternative energies for the metal-free polymerisation of PLA, replacing metal-containing catalysts by organic ones and purifying the polymer using the degassing ability of a Gneuss’ (a consortium member) MRS device.
The project, which started in December last year and runs until May 2016, also hopes to obtain energy savings and a single monolayer packaging that may be processed by polymer processing, extrusion and injection technology.
InnoREX aims to develop PLA grades, blends and PLA-based composites using alternative energy sources.
To ensure short market entry times commercially established co-rotating twin screw extruders will be used as reaction vessels.
The reason commercial polymerisations are not yet carried out in twin screw extruders is the short residence time and the static energy input of the extruder, which allows no dynamic control of the reaction, explained the project brief.
Prototype model
A working polymerisation line incorporating alternative energy, online characterisation technology and a purification device to remove the catalyst will be developed as a demonstrator.
The prototype obtained will be a single thin walled monolayer packaging (of a thickness possibly not exceeding a millimeter) intended for the food sector.
Analysis of the thermo-mechanical behaviour evolution along the extrusion process will be carried out within the Ludovic software and models and characteristics of the PLA polymerisation method will be integrated to optimise the management of experimental trials and product quality.
The Technological Institute of Plastics AIMPLAS, along with eleven other enterprises and technological European centers, launched the project, which is coordinated by the German Fraunhofer Institute for Chemical Technology - ICT.
French firm Roquette and the Finnish company Huhtamaki are also involved in the project as observers.