Coconut husk has far vital practical uses: Dutch expert
Alappuzha, Feb 3: Often discarded as unwanted and unusable, the coconut husk has a number of practical applications beyond serving as mulch, Coir Kerala 2016 was told today. An international seminar at the five-day event saw expert Prof. Edwin R. P. Keijsers outlining the qualities and benefits of flatboards made up from coconut husks.
“In Kerala and other places, coir husks are being discarded as waste. However, there are many possibilities for husk-based products in sectors like construction and packaging,” the Dutch speaker told the session titled ‘Binderless Boards from coconut husks’, as part of the general theme of product diversification.
A team led by Prof Keijsers, who is affiliated with the Food and Bio-based research group at Wageningen University in the Netherlands, has developed two kinds of husk-based boards: high-quality boards with a higher density (and weight), better mechanical properties with more production costs and longer production times; and less expensive, quicker to produce medium-quality boards.
“The boards are developed by milling, steam pressing and cooling the husks. They require no glue or resin to hold together,” he said. “They absorb water without swelling and are flexible enough to bend without breaking; this makes them resistant to fire.”
Stress tests done on the boards produced from husk show that the water absorbent and flame retardant properties of these products are superior to most other woods used today, including medium-density fibreboard, plywood and hardwood.
Besides giving the board its remarkable fire retardant property, “the ability of coir fibres to bend and stretch at 45-degree angles” makes it ideal for use in building construction. The higher concentration of silica in coir is important as well.
“The medium quality board resists catching fire for three minutes, while the high quality board starts to burn after five minutes. By comparison, hardwood burn after one minute,” Prof Keijsers said. “Only 10 per cent of the weight of the board is lost in a fire whereas other types of wood like MDF and plywood lose much more. Hardwood, for instance, falls apart.”
Additionally, the gaps or spaces inside coir fibres allow water to permeate it without causing the product to stretch, allowing for the boards to be used in high-moisture environments.
“The boards can be sawn, sanded, painted and waxed, but are hard to drill to very tough to screw a nail in—the force required to hammer a nail in these boards is almost twice that needed for hardwood,” he said.
Regardless, he said, the boards offer a number of practical benefits in tropical climes.