Kapok – the pagoda-shaped tree

One good way to identify a tree sometimes is to observe the tree architecture. There are a number of trees with pagoda-like architecture (meaning the branches arranged in layers like the different storeys of the pagoda which taper towards the top). Examples of such trees are ketapang tree (Terminalia catappa), Pelai (Alstonia scholaris) and kapok tree (Ceiba pentandra).



Kapok tree or Ceiba pentandra (Bombacaceae) at the Padang Merdeka in Kuching


Kapok tree or Ceiba pentandra belongs to the Bombacaceae family and is native to Africa as well as Central and South America but different varieties exist on both sides of the Atlantic Ocean. Ceiba pentandra is the national tree of Guetamala.

Kapok fibre is obtained from the fruits or seed pods which contain seeds surrounded by a fluffy and yellowish fibre. Kapok fibre has a significantly homogeneous hollow tube shape and is composed of cellulose (35% dry fiber), xylan (22%), and lignin (21.5%). Kapok fibre is significantly hydrophobic (meaning it does not absorb or get wet with water) and is suitable as fiberfill in pillows, quilts, and some soft toys. Cushions for outdoor use such as on yatch and garden set are still sometimes stuffed with kapok fibre.



Plastic bagful of kapok for sale at Sirikin, the border town with West Kalimantan.

During my childhood, my pillows were stuffed with kapok fibre unlike pillows of today. That was before the advent of synthetic material. My mother would from time to time took out pillow covers to wash and then left the pillows in the hot sun. After which he would beat the pillow with a rattan beater to remove and dust particles. Maybe that’s the way to sterilize the pillow.









Kapok fibre and seeds underneath a kapok tree.

Fortunately, in recent years, kapok fibre has found new uses. Among them are as oil absorbent and in industrial applications. As the fibre is hydrophobic and at the same time selectively absorbed significant amounts of oil (40g/g of fibre) from an oil suspension in water, kapok fibre has been used to recover oil spills in seawater and freshwater and for removing entrained oil from waste water.

Even though kapok fibre is able to be applied in various industrial usages, it has a serious disadvantage which is the extreme sensitivity to spark or flame due to its hydrophobic nature. However, kapok fibre can be converted into a flame-resistant fibre by gamma ray treatment which removes the hydrophobic compounds and cleavage of methoxyl group from lignin polymer.

Now, isn't that wonderful?