The Institute of Design and Furniture of the Faculty of Forestry and Woodworking of Mendel University has been working to develop materials for furniture production from a range of alternative materials, including hemp, rapeseed, and flax. As the population on the planet increases, so does the demand for furniture, but there is not enough wood to satisfy this demand. Alternative materials such as post-harvest residues from the cultivation of technical hemp for seed can be pressed into the form of boards, which can be used as a substitute for wood for both construction purposes and furniture production.
The hemp stem is most similar in structure to wood, but has a number of advantages. “One hectare of hemp absorbs four times more CO 2 compared to wood, and four times more mass grows on one hectare. The time it takes for hemp to grow can be 80 days, while we are talking about 40 to 120 years for wood. Moreover, it is a resistant plant that does not need pesticides or herbicides,” explained Milan Gaff, head of the Institute of Design and Furniture.
“Hemp stems are dried, impregnated with soy starch, pressed and baked, or even impregnated with oil,” he said. “We develop three types of boards from hemp and other alternative materials: chipboard from a small fraction below 5 mm, another from a fraction below 8 cm or from whole stems. Each has its advantages and disadvantages, but compared to classic chipboard, they are much stronger, suitable for construction purposes and for furniture.”
Residues from technical hemp are used for the production of boards. From a 2-3-metre plant, only the top metre at most is harvested for seed; the stem remains and is not used, and it is this part that is ideal for the production of boards.
Due to the great shortage of some materials, there is a great interest in alternatives. LDF MENDELU scientists are also testing the production of boards from other raw materials, such as corn, sunflower, rapeseed and flax. Of the materials commonly available in the Czech Republic, however, the properties of hemp clearly have the most potential. There are also variants produced in other countries made of coconut, straw, pine needles, and sea grass. “Every morning, millions of tons of seaweed wash up on the beaches and are cleaned up and taken to landfills. If sea grass is used to make boards, it will at least find a meaningful use, ” Gaff explained.
The use of alternative raw materials for the production of furniture is one of the ways to solve the lack of material. The second option is repeated recycling. “Hemp is one of the materials of the future and one of the small paths we have,” said Gaff. “Most of the furniture produced today is second or third generation recycled material with decorative material glued to the surface. However, sustainability is limited with repeated recycling; the mechanical properties and density of the material deteriorate, as petroleum products and adhesives are part of the product.”
Wood-based chipboards began to be mass-produced from the 1950s due to the growing demographic curve. “The main reason was that the yield in wood production was around 35%, in the case of bent furniture 25%, so there was a lot of waste that was burned,” explained Gaff. “When the waste material was milled and made into fibreboard, the range expanded and up to 95% of the wood that did not end up in the incinerator were used. That was a big positive.”
Chips from recycled wood instead of virgin wood started to be produced later. According to Gaff, that helped offset slightly the need to scale up and make the products financially viable. However, it still wasn’t enough, so they began looking for new alternative materials, ideally based on lignin and cellulose.
