Here is a list of composite woods that are mainly obtained from forests.
Composite Wood # 1. Laminated Wood:
It is built up product made of wood layers (laminae), all laid with their grain parallel and glued or fastened together. Laminae may be the thin veneers or boards cut in uniform width and length arranged in proper order and fed into glue spreader and pressure is applied. Laminated are wood used in furniture parts, cores of veneered panels, sports goods, aero-plane hangers, auditorium, exhibition halls, gymnasia, planetariums, theaters, warehouses, etc. They are also used in flooring, picker sticks, boat and ship timber, aircraft parts, diving boards, etc.
Composite Wood # 2. Glulam:
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It is a glue laminated timber. They are manufactured from solid sawn lumber. The lumber is glue jointed end to end and then these “long laminations” are then glued face to face resulting in beams up to 90′ in length. They are used in commercial constructions and residential constructions.
Composite Wood # 3. Chipboard:
It is made by compressing and gluing small chips of waste wood. When in use, it is normally covered by a plastic coating for hardwood veneer.
Composite Wood # 4. Core Board:
It is a composite board built up of a core composed of strips of wood of various dimensions glued together or jointed together to form slab which in turn glued between two or more outer veneers with the direction of the grain of the core strips running at right angles to that of the adjacent veneers. It is batten board when the strips of the wood are not more than 7.5 cm wide and Block board when size is not more than 2.5 cm.
When each strip of wood has a thickness of not more than 7 mm, it is called lamin board. Core boards also covered with outer layers of fibreboard, synthetic resin fibres, metal sheets, sunmica, etc. Due to their low weight, better stability, good acoustic and heat insulation properties, they are used for doors and partition in residential and office construction.
Composite Wood # 5. Sandwich Board:
They are built up board having a core of light material, faced on both side with relatively thin layer of material having high strength properties. Sandwich constructions are composites of different materials bonded together in a unit to achieve a combination of desirable properties. Two thin facing (skins) are usually of a strong dense material for load bearing. They are used in aircrafts, motor boats, table tops, flush doors and containers.
Composite Wood # 6. Fibreboard:
It is a sheet of material made up from fibres of wood. The wood is first defibrated or pulped and fibres are then inter-felted into a mat and consolidated by pressure and heat. Bonding agent and supplementary material may be added at the felting stage to improve the mechanical properties. Fibre boards are used as core material in core board and sandwich board.
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Such boards are designated as building board, insulating board, wall board etc. As per densities, they can be grouped hard boards, semi hard boards, medium hard boards and soft boards. Fibre boards are made up from agricultural or forest waste material (lops & tops), waste veneers, etc.
They are used in panels, insulating and cover material in buildings and office cabinets. Medium Density Fibreboard (MDF) is made from fine wood fibres, compressed and glued together. When in use, it is normally covered by a plastic coating or hardwood veneer.
Composite Wood # 7. Particle Board:
It is board or sheet constituted from fragments of wood and other lignocellulosic material, bonded with organic binders with the one or more agents like glue, heat, pressure, humidity, catalyst, etc. It uses chips, flanks, splinters, sawdust and as per material used these are called chip board, flake board, shaving board, bamboo board, etc. They are used only for interior housing or furniture and not suited for exterior use.
Composite Wood # 8. Hardboard:
It is an engineered wood product manufactured from wood chips that are mechanically reduced to wood fibres and then bonded together into panels through heat and pressure. These panels are grain less, dense, uniformly textured, strong and bone dry. They are humidified and trimmed to size.
Composite Wood # 9. Wood Fibre Composites:
Recycled wood fibre can be used to make composites from particles or fibres of wood held together with an inorganic matrix, such as Portland cement or gypsum. Such composites can be used in a variety of structural and industrial applications and have unique advantages over conventional building materials. Some composites are water resistant and can withstand the rigours of outdoor applications.
Almost all are either fireproof or highly fire resistant and are very resistant to decay by fungi. Inorganic-bonded wood composites are molded products or boards that contain between 10 and 70 per cent (by weight) wood particles or fibres and conversely 30 to 90 per cent inorganic binder. Many different types of material can be incorporated with the inorganic binder matrix, including recycled paper fibre, fiberized demolition waste or scrap pellets, industrial waste wood, wood residues, non-commercial wood species and very low grade, non-merchantable wood.
The wood particles must be fully encased with the binder to make a coherent material. Thus, the amount of inorganic binder required per unit volume of composite material is much higher than that in resin-bonded wood composites. The properties of inorganic-bonded wood composites are significantly influenced by their density as well as the amount and nature of both the inorganic binder and the woody material.
Cement-bonded particle and fibre boards possess excellent machinability, thus allowing builders to construct a wall product for home construction that combines studs, sheathing and siding into a single panel. Other uses include cladding, balcony parapets, flooring, industrial walls, sound barriers, garden and fence walls, interior partitions and wall linings in areas of high humidity.
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Gypsum-bonded wood fibre panels are used as replacements for gypsum wallboard and are reported to have strong nail and screw-holding properties, high moisture and fire resistance and improved resistance to impact, mold and mildew. Other reported advantages of gypsum-bonded wood fibre panels compared to conventional gypsum wallboard include improved anti-sag properties for ceilings, better sound insulation, and a system for finishing joints that doesn’t require tape.
The combination of wood fibres with inorganic binders provides a unique opportunity to utilize recycled waste and low-grade wood fibre to make products that are environmentally safe, user friendly and acceptable for many uses. Research to date has clearly indicated that inorganic-bonded wood composites can meet building and industrial needs.
Composite Wood # 10. Panel Products:
Fibre-based panels of varying densities can be produced from recycled wood fibres. One family of products, called Homosote, was first produced in 1916. It is made from recycled newspapers and other ground wood paper publications. Other fibreboard-type products on the market also use all or partly recycled wood fibre as a raw material base stock.
Uses for these types of products include insulating acoustical board, carpet board, and nail baseboard. Many other uses for fibre-based products of this type will be developed, when collection, separation and cleanup processes are further refined and developed.
Composite Wood # 11. Wood-Plastic Mats:
Another potential use for recycled wood fibre is in low-density mats. Wood and plastic fibres are introduced into a turbulent air stream, transferred via the air stream to a moving support bed and subsequently formed into a continuous, low-density mat. The fibres in the mat are further intertwined and strengthened through needling.
The ratio of wood to plastic in this matrix can be in the range to 95 to 5 per cent by weight. The plastic can also be replaced with a long lignocellulosic fibre such as jute or kenaf. An interesting application for fibre mats is for mulch around newly planted seedlings. The mats provide the benefits of natural mulch. Application for low-density wood fibre mats is for air filters or other types of filters.
Some other synthetic products:
i. Wood-Based clear Packaging Film:
It is a wood-based material with properties like plastic, suitable to be used as packaging material. These include food packaging, where the material – nano fibrillated cellulose film (NFC) – can help increase the shelf life of a product.
ii. Wood Fibre Bioplastic Packaging:
Biodegradable plastic food packaging is made using up to 25 per cent wood fibres.