Kapok Fibre

Kapok (Ceiba pentandra) is a seed hair fibre obtained from the seed pods of the tropical kapok tree, producing 200–400 kg of fibre per hectare across Indonesia (70% of world production), Thailand, Cambodia, and West Africa. Kapok fibre is 10–35 mm long, 20–40 µm diameter, extremely fine hollow cylindrical structure with lumen-to-total cross-section ratio of 80–90% (versus 20–30% for cotton), and cell wall thickness of only 1–2 µm. Cellulose content is 60–65%, lignin 13–15%, and wax 3–5%. Bulk density is extremely low (25–45 kg/m³) due to hollow structure; oil absorption capacity is 30–40× own weight for hydrocarbons versus 18–25× for cotton. Thermal conductivity of 0.034–0.036 W/m·K qualifies kapok as a natural thermal insulator. Global kapok production is 130,000–150,000 tonnes/year valued at $80–120 million.