Binderless boards from coconut husk

Projects for product diversification in coconut husk were discussed at a seminar held on Thursday as part of an international coir fair now on in Alappuzha. There are many possibilities for husk-based products in sectors such as construction and packaging, Edwin R.P. Keijsers, who is affiliated to the food and bio-based research group at Wageningen University in the Netherlands, said at a session on “binderless boards from coconut husk.”

A team led by Mr. Keijsers has developed two kinds of husk-based boards, one high-quality board with a higher density and the other of medium quality. The former is costly while the latter is cheaper and quicker to produce, he said. The boards are developed by milling, steam pressing, and cooling the husks. They require no glue or resin to hold together.

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 the products are superior to most other woods used now, 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 only after five minutes. In comparison, hardwood burns after one minute, Mr. 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. The gaps or spaces inside coir fibres allow water to permeate it without causing the product to stretch, which makes it convenient for use in high-moisture environments. The boards can be cut, sanded, painted and waxed, but are hard to drill. The force required to hammer a nail in the board is almost twice required for hardwood, he said.

They absorb water without swelling and are flexible enough to bend without breaking

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Printable version | May 27, 2022 9:09:56 am |