Oriented structural straw board (OSSB) is an engineered board that is made by splitting

straw Straw is an agricultural byproduct consisting of the dry wikt:stalk, stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the crop yield, yield by weight of cereal crops such as barley, oats, rice, ry ...

and formed by adding

methylene diphenyl diisocyanate Methylene diphenyl diisocyanate (MDI) is an aromaticity, aromatic diisocyanate. Three isomers are common, varying by the positions of the isocyanate groups around the rings: 2,2′-MDI, 2,4′-MDI, and 4,4′-MDI. The 4,4′ isomer is most widel ...

(MDI) and then hot compressing layers of straw in specific orientations. Research and development for OSSB panels began in the mid 1980s and was spearheaded by the Alberta Research Council, Canada (today AITF).

Uses

OSSB can replace wood

oriented strand board Oriented strand board (OSB) is a type of engineered wood, formed by adding adhesives and then compressing layers of wood strands (flakes) in specific orientations. It was invented by Armin Elmendorf in California in 1963. OSB may have a rough and ...

(OSB) and particle board in structural and non-structural applications, such as interior and exterior walls for house construction, furniture and interior decoration. OSSB panels are formaldehyde-free, they are also used for applications where air quality is a concern, such as kindergartens, hospitals, bedrooms, and hotels.

Manufacturing

OSSB panel manufacturing starts with careful selection of straw fibres, which are then cut, cleaned, split and dried. Splitting straws allows resin to coat what would otherwise be the inside of a hollow straw. Producing split straw of sufficient length was the key technical innovation making OSSBs possible. OSSB is thus sometimes referred to as oriented split straw board. Formaldehyde free resin is added to the straw and the fibres are oriented for strength and appearance, and shaped into a mat through directional mat forming. The mat is then pressed between heated belts, water is vaporized, transferring heat into the straw. The heat cures the adhesive and causes a series of physical and chemical changes to the pressurized raw materials, which harden the final product.

Properties

OSSB panels have high structural strength, load bearing and stability in both directions, as well as superior workability and excellent nail holding properties on all sides. Water permeability treated OSSB panels are more water resistant than treated traditional wood panel boards because they have no internal gaps or voids. OSSB panels are also highly earthquake resistant. The resin used to manufacture OSSB is p-MDI, which does not emit

formaldehyde Formaldehyde ( , ) (systematic name methanal) is an organic compound with the chemical formula and structure , more precisely . The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as ...

(

volatile organic compounds Volatile organic compounds (VOCs) are organic compounds that have a high vapor pressure at room temperature. They are common and exist in a variety of settings and products, not limited to house mold, upholstered furniture, arts and crafts sup ...

/ VOCs). The raw material can be treated by various

borate A borate is any of a range of boron oxyanions, anions containing boron and oxygen, such as orthoborate , metaborate , or tetraborate ; or any salt of such anions, such as sodium metaborate, and borax . The name also refers to esters of su ...

compounds, which are toxic to termites, beetles, molds, fungi and mammals, but only at higher doses.

References

{{Reflist Composite materials

Uses

Manufacturing

Properties

See also

References