Physical Characteristics of Kapok Fiber (fibre)

Individual kapok fibers are 1 to 1.5 cm in length. Under a microscope, kapok fibers present a long narrow cell with frequent folds. Its cell has thin walls and a hollow structure. Its walls form a smooth, closed tube with a large cavity called a lumen.  Each kapok fiber is coated with a waxy substance called cutine. The cutine and lumen are thought to give kapok its buoyancy. Chemically, kapok fiber consists mainly of cellulose, although also containing pentose-containing polysaccharides called pentosan and an inert plastice-like material called lignin.