Natural fibres were the first fibres used for thermosetting resin reinforcement but slowly they fell into disuse for performance and environmental problems principally due to low mechanical properties, high moisture absorption, ageing sensitivity and recycling difficulties. Now, there is a renewed interest for natural fibres due to ecological trends, economic circumstances, geopolitical reasons:
1. Sustainability: apart wood, their origin is in fast growing plants. Even for wood, renewing duration is far shorter than the fossil energy used for glass fibre production.
2. Geopolitical motivations: many plants grow in developing countries and need agricultural means instead of industrial ones.
3. Environmental motivations: the production of natural fibres saves energy and decreases pollution.
4. The ecology wave becoming a buoyant marketing argument.
Recently, thanks to biofuels issues, the other side of the coin appears with possible detrimental effects on food and industrial crops.