NanoSteamEx - Production of microfibrillated cellulose by a steam explosion process

Nano/Micro-Fibrillated Cellulose (M/NFC) have gained increasing attention for the production of new innovative materials due to their remarkable properties. The defibrillation of M/NFC generally requires intensive and energy consuming mechanical treatment which is preceeded by chemical and/or enzymatic pretreatments. The high cost of these extraction processes constitutes one of the main limitation of the M/NFCs broad utilisation.

The objective of NanoSteamEx is to propose an innovative low-energy and environmentally friendly combinative process for the production of M/NFC from bleached chemical kraft fibres, softwood and hardwood and non woody plant. The main originality of the project is to combine a steam explosion pretreatment with an organosolv/ionic liquid delignification (with ethanol or 1-ethyl-3-methylimidazolium acetate) followed by refining / grinding steps. An important part of the work is devoted to the development of reliable methods to characterise M/NFC in terms of morphological properties and chemical composition (hemicelluloses, lignin content, DP of cellulose).

The final goals are

1. to reduce the energy consumption of the M/NFC production by reducing the energy necessary during the pre-treatment grinding steps
2. to tune the M/NFCs properties as a function of their chemical composition and their cellulose structure,
3. to isolate a pure lignin fraction from the organosolv process for further utilisations.

Different raw materials are used in order to evaluate the potential of the studied process with a particular interest in:

• Proposing ways allowing to reduce energy consumption throughout the production process,
• Producing M/NFCs with tuned properties in particular regarding the content in hemicelluloses/lignin and the degree of polymerisation (DP) of cellulose,
• Extracting lignin using mild chemical delignification steps coupled to steam explosion,
• Investigating the end-use properties of the N/MFCs for two specific applications.

Applications in the fields of packaging (films or nanopapers) and wood particleboard (tannins-based adhesives) will be considered.