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Bioderived and sustainable material solutions

CALMARE has continued to work with companies using bioderived and natural materials, following on from previous research by the X-AT centre.

Projects include:

Here at Exeter, TARF-LCV aims to develop advanced polymer matrix composites - sheet moulding compounds (SMC) and dough moulding compounds (DMC) using recyclable natural fibres for LCV structures that are light in weight, sustainable, disposable and have similar performance (mechanical, environmental resistance, surface finish etc) to man-made fibre reinforcement.

Partners: Brunel University, University of Manchester, University of Strathclyde, Imperial College, London, University of Nottingham, Coventry University, Oxford Brookes University

Funded by: EPSRC


The business

The Provenance Company is a producer of twine and rope, under the brand name Twool, from the wool of Whiteface Dartmoor sheep. Twool started as a British garden twine
product, providing a local, sustainable alternative to imported jute. The Whiteface Dartmoor breed is known for having wool with a long staple length, suitable for spinning
a twisted worsted yarn. Success with this product has led to a variety of colour choices, the development of thicker rope versions, both plaited and twisted, and the continuing
development of further lines.

The challenge 

CALMARE was challenged to find the physical properties of a variety of Twool products and to see how these compared in stiffness and tensile strength to other materials. The
centre carried out a number of physical tests on twine, polypropylene twine, plaited rope, twisted worsted rope and large twisted worsted rope, and conducted research into
the properties of wool, twine and rope.

The result

CALMARE put together a report of its findings, which demonstrated that these new sustainable products offered similar physical properties to less sustainable and more
commonly used materials. The twine, although having a slightly lower breaking strength, had increased elasticity, which could be of significant benefit in its main application as garden twine around trees and plants, allowing for more movement. The ropes, particularly the thicker ones, showed similar strength to standard products, with the barrier rope holding a force of just under 1.8 tonnes (approximately the weight of a Ford Mondeo).

This information is of great benefit to support the company’s decisions about the strategic direction and to validate its belief in its products. It is continuing to develop new products from sheep’s wool and was shortlisted for Product of the Year at the Chelsea Flower Show in 2013 and 2014.

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Devon-based manufacturing business Solidwool has created a composite product - the Hembury Chair - using fleece from upland UK sheep as reinforcement. Made using wool from the Herdwick Sheep of the Lake District and having been showcased at design shows in London and Milan, the Hembury Chair has attracted interest from high end department stores.

Originally, the composite chair was moulded as a single piece using a resin infusion technique, allowed to harden at room temperature and post-cured (exposed to elevated temperatures to maximise its physical properties). CALMARE was called in to assess whether the process used was resulting in optimum levels of strength and flexibility. The Centre was able to suggest improvements to the post processing method, which were verified through a testing programme combined with the testing to demonstrate the enhanced physical properties. 

» Download this case study as a PDF