Cellulose – the old new wonder material

Would you believe it (should that read wood you believe it?), that stuff that plants are made of turns out to be super strong, if you make it right.

According to ‘Multiscale control of nanocellulose assembly: Transferring remarkable nanoscale fibril mechanics to macroscale fibers‘, published in ACSnano, a US/European team has found a way to align and cross-link ‘cellulose nano-fibrils’ (CNFs) to create a material that scores 86GPa Young’s modulus and 1.57GPa tensile strength “exceeding the mechanical properties of known natural or synthetic bio-polymeric materials”, according to the abstract.

Note, CNFs (cellulose nano-fibrils) not to be confused with CNTs (carbon nano-tubes).

That said, I was once shown how to make stinging nettle string (not as painful as it might sound, but takes ages) and it is very strong – apparently stinging nettle fibre also scores around 86GPa Young’s modulus, according to Mr Wikipedia.

I think the point here, is that attempts to artificially align CNFs have previously produced only weak fibres, according to ACS (American Chemical Society), but using a flow-based artificial assembly process, this team has made fibres with well-aligned CNFs, and they are properly strong.

“Most importantly, the macroscale fibers were stronger than metal, alloys and glass fibres. And they are both stronger and eight times stiffer than drag-line spider silk, which is the gold standard for lightweight bio-polymers, at the same specific strength. The researchers say that the material could be useful in many load-bearing applications, such as light-weight bio-based composites for cars and bikes, as well as high-performance medical implants,” according to ACS.


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