Natural fiber composite wheelchair seat design aims for sustainable mobility

On June 9, the National Composites Centre (NCC, Bristol, U.K.) announced that it has collaborated with global disability charity and social enterprise Motivation (Bristol, U.K.) to design and manufacture a wheelchair seat pan made entirely from sustainable, green, composite materials intended to improve the quality of life for disabled people in developing countries.

According to the NCC, there are 75 million people worldwide in need of a wheelchair, and 80% of them live in developing countries. The NCC says it was approached by Motivation, which provides wheelchairs, training and services to disabled people in low- and middle-income countries, for help in developing and proving a new wheelchair seat pan concept that would be robust enough to cope with tough terrain, affordable to produce, made from bio-based materials that could be locally sourced, and offer a solution that is lightweight, durable and hygienic. 

Motivation currently produces wheelchair cushions from polyurethane (PU) foam, which sit on either fabric “slung” seats that are tensioned between framed sides, or a plywood base. There are benefits to these designs and materials, such as providing needed postural support and pressure management. However, according to the NCC, constant and prolonged use of fabric seats can result in stretching that compromises user posture, and plywood may degrade. The sculpted foam cushion may also degrade or become unhygienic due to hot, humid climates and potential soiling. 

In response, the NCC worked with Motivation to design and manufacture a prototype flax fiber composite wheelchair seat pan that can be uniquely molded to the user to ensure a surface that provides long-term postural control and pressure management. A thin cushion can then be added, replacing the sculpted PU cushions currently in use. This new design is said to be lighter than the plywood equivalent and to provide more durable, reliable physical support and postural control. Furthermore, it is reportedly easier and cheaper to replace the thin foam liner of a seat pan than a PU cushion.

Gurit (Newport, Isle of Wight, U.K.) flax fiber and Sicomin (Châteauneuf-les-Martigues, France) Infugreen resin were selected as the base materials to demonstrate the new design. According to the NCC, these materials enable lower-cost manufacture compared to traditional composite materials, and can be traded for other locally sourced natural fibers as available. The overall costs to manufacture using composites is slightly higher than the previous materials, the NCC reports, while providing long-term durability and quality benefits.

Adam Healey, a research engineer at the NCC who led the project team, says, “This is the first ever wheelchair seat pan made entirely from green materials for the developing world market. ... There is so much scope to optimize this design further, and many opportunities to explore the end-of-life potential so that the seat pans can be easily recycled, bringing even more environmental benefits. This opens the door for us to make more wheelchair components out of green composites.”

Ian Harris, senior designer at Motivation, adds, “Motivation’s collaboration with the NCC has allowed us to realize the production of a prototype seating pan that had existed as just an idea in our heads. Together we’ve been able to create an exciting concept for a solution to real-world challenges faced by wheelchair users in low- and middle-income countries.”

This R&D project was funded by Sustainable Composites, a partnership between the NCC and CPI, two members of the U.K.’s High Value Manufacturing Catapult