Natural fibres take advantage of economic and environmental trends. Moreover they are cheaper than fibreglass, but exhibit lower performance and sometimes compete with food crops leading to an economic unbalance. Certainly, there is a renewed interest in natural fibres due to ecological trends, economic circumstances, geopolitical reasons but consumption is rising at a slow pace because of some bottlenecks such as lower mechanical characteristics, ageing performances, force of habit and a shorter experience compared to fibreglass. Under ecological pressure, the rate of growth is expected to increase faster in the near future but a worldwide crisis is necessary to launch a true takeoff. Two major hypotheses are conceivable: in the next years, a strengthening of the environmental constraints and in the distant future, of petrol drying-up.
On the one hand, natural fibres present many advantages as they are sustainable by nature, and respond to geopolitical, environmental and ecological motivations. Apart from wood, they are sourced from fast growing plants. Even for wood, the renewal duration is far shorter than that for the fossil fuel used for glass fibre production. Many plants grow in developing countries and need agricultural means instead of industrial ones. The production of natural fibres saves energy and decreases pollution, and the ecology wave is becoming a buoyant marketing argument.
On the other hand, they suffer from some drawbacks such as the availability of high industrial quantities, higher variations of quality due to the natural origin of vegetal fibres (growing areas, batches, years and seasons); the lower performances compared to fibreglass, a high moisture uptake, the possible poorer surface aspect of end parts, a sensitivity to high temperatures and UV, limiting outdoor exposure and/or high-temp applications. The lack of experience, the routine and a non-qualification in most industrial parts are also major obstacles to their application.
Intensive research in agricultural, spinning, fibre treatments, sizing and use, exploitation of non-competing crops and low value wastes, an eco-design and thinking out of the box can contribute to speeding up the use of natural fibres.