A Canadian company believes it can mass-produce strengthening nanoparticle additives derived from cellulose in trees.
Celluforce has built a pilot demonstration plant to produce its particle, which is one-third as strong as carbon nanotubes (though still eight times stronger than steel) but much cheaper and safer with additional optical properties.
‘We’re using the material that is the structural building block of trees — what allows them to stand tall under storms — but taking out the weaker parts that make it flexible,’ said Jean Moreau, chief executive officer of Celluforce.
Applications are broad but include composites for aerospace, transportation and medical devices; high-strength textile fibres; switchable optical filters; and iridescent pigments.
The early work on nanocrystalline cellulose (NCC) was done by scientists at FPInnovations under Dr Richard Berry — now chief technology officer at Cellulose — who initially trained at Keele University.
Noram Engineering, with financial assistance from Domtar, then scaled up production with a CAN$33m (£20.5m) facility at the site of an existing pulp plant, which was completed earlier this year.
The aim is to produce 1,000kg of the nanocrystalline cellulose (NCC) particle — which is 100nm in length and 5nm in diameter — per day by the end of the year.
Essentially, cellulose from kraft pulp is first milled and then hydrolysed to remove amorphous regions.
‘The key difficulties we are experiencing now are that several of the operating units have never been built before, and the engineers have never seen this material before, so we have challenges with our filtration. As we’re looking to go to full commercial production, some of those unit operations cannot be scaled up so we’re looking at alternative technologies,’ said René Goguen, vice-president of manufacturing at Celluforce.
The resulting NCC is then separated and concentrated before being customised for various uses.
‘We have what we call vanilla NCC, but there are surface modifications depending on the environment that you’re working with; if you’re working towards a hydrophobic environment you will have to modify the surface so there is post-modification manufacturing,’ said Moreau.
In all, eight tonnes of wood are required for one tonne of NCC and it is hoped commercial production can tap into Canada’s vast forests and revive an ailing pulp industry that has been hit by the decline of printed media.
Celluforce says its NCC is sustainable, biodegradable, practically non-toxic, and potentially re-claimable.