Why Is Wood Important in Chemistry?
Wood is a hard-fibrous material building the trunk and branches of trees or shrubs. The trees are first grounded, and the wood logs are then cut in the sawmills to smaller sizes, and these wooden pieces are then used for making furniture. The most famous and largely used wood type is softwood that is Plywood's.
The Density of Wood
Wood density affects how timber is classified and where it can be used. The relationship between timber hardness and density :
< 480 kg/m3 -Very soft
485–560.kg/m3 -Soft
565–800.kg/m3 -Firm
805–960.kg/m3 -Hard
> 965 kg/m3-Very hard
Characteristics of Wood
It is lightweight and strong
Wood maintains its thermal properties, therefore it is resistant to high temperatures
Heat conductivity of wood is comparatively low contrasted to aluminum, marble, steel, or glass
It can absorb noise and echo especially in Plywood's
It is not a good conductor of electricity.
Wood Advantages
To contribute to sustainable development the wood and its derivative products are the best suitable material because of the technician and environmental qualities.
Apart from is an eco-friendly material, wood brings other great features like high stability, strength, flexibility, versatility that make the wood products one of the biggest references of the habitats, decoration, construction, packaging. Wood is the only material that decreases the CO2 radiation, as plays an essential role to slow down Climatic Change.
Wood as a Material: Different Uses
The total number of wood-based items is enormous—some figures put it as high as 10,000. The versatility of wood, as well as its many desirable qualities, such as high strength for its weight, workability, and aesthetic appeal, allow such broad application. However, there are several drawbacks to using wood. It will, for example, fire and decay. It is hygroscopic (moisture-absorbing), and it changes dimensions as it absorbs or loses moisture. Furthermore, as a biological product, wood has a wide range of quality. Understanding the dynamic nature of this material is important for reducing the effects of these inherent undesirable properties, as well as making proper use of the many existing wood-growing plant species and producing the best possible wood quality in the forest. An analysis of the structure, chemical composition, and properties of wood may provide this insight.
Classification of Wood
Wood can be broadly categorized as Softwood and Hardwood. Density is a significant determinant of the durability of wood. Hardwoods, meaning denser than softwoods, are more effective and more long-lasting.
Softwood – It originates from the coniferous trees. These trees are also identified as evergreen trees as leaves do not drop till the new ones develop. Softwood normally grows in areas having a cold climate. Coniferous trees grow fast; therefore, they are less costly as compared to hardwood. They are more sustainable as they can be readily grown. Soft Wood has shades of yellow or red and is less costly compared to Hardwood.
Softwoods are Often Used for:
Panels
Plywood
Particleboards (compressed wood)
Dry-erase boards
Toys
Hardwood – It originates from deciduous trees that have broad leaves, provides fruits or nuts, and are usually inactive in the winter. Hardwoods have an extra dense structure about softwoods. Hardwood has darkened shades of red and brown and is a bit high-priced.
Hardwoods are Often Used for:
Flooring
Furniture
Utensils
Boats
Baseball bats
Instruments
Model aircraft (Balsa)
Types of Wood for Furniture Especially:
Softwood:
Plywood (highly popular in furniture making)
Pinewood
Cedarwood
Spruce wood
Deodar wood
Hardwood:
Teakwood
Rosewood
Oakwood
Maple wood- Rubberwood (Environment friendly)
Marandi wood
Why Buy Rubberwood and Its Uses?
Rubberwood is a light-colored, moderate tropical hardwood derived from the Pará rubber tree (Hevea brasiliensis), which is typically found in rubber plantations. Rubberwood is sometimes marketed as an "environmentally friendly" wood because it is made from plantation trees that have previously served a useful purpose. Rubberwood has a thick grain that is easily managed in the kiln drying process. This material is used for making furniture, toys, and kitchen accessories. It has a depth of approximately 9500 psi, stiffness of 1.3 million psi, and hardness of 500 pounds.
How Plywood is a Better Choice for Furniture?
Plywood is a smart option for most types of use that includes walls, subfloors, and furniture. The benefits of plywood hold its availability and price, as long as you aren't set on the more costly hardwood varieties. It is very hard and the thinner cuts are effortless to work with. Plywood that is covered with a good quality cover can be painted to look like any wood and is smooth to paint.
The Types of Plywood You can Choose:
Softwood plywood
Hardwood plywood
Tropical plywood
Aircraft plywood
Decorative plywood (overlaid types of plywood)
Flexible plywood
Marine plywood
FAQs on Wood in Chemistry: Types, Properties & Applications
1. What is wood from a chemical perspective?
From a chemical standpoint, wood is a natural organic composite material. It is primarily composed of a complex matrix of polymeric substances that form the rigid, fibrous structure of tree stems and roots. The three main chemical components are cellulose (about 40-50%), hemicellulose (about 25-35%), and lignin (about 15-30%), along with minor amounts of extractives and inorganic minerals.
2. What are the two primary types of wood and how do they differ chemically?
The two primary types of wood are softwood and hardwood. Their main chemical differences are:
Softwood: Obtained from gymnosperm trees (like pine and spruce), softwoods generally have a higher lignin content and a lower cellulose content compared to hardwoods. The primary hemicellulose in softwoods is glucomannan.
Hardwood: Obtained from angiosperm trees (like oak and maple), hardwoods typically have a higher cellulose content and a different type of lignin (syringyl-guaiacyl lignin) than softwoods. The main hemicellulose in hardwoods is xylan.
3. What are the key chemical properties of wood?
The key chemical properties of wood are determined by its main components. These include:
Hygroscopicity: The ability to absorb and release water from the surroundings, primarily due to the hydroxyl (-OH) groups in cellulose and hemicellulose.
Combustibility: Wood can undergo combustion, a chemical reaction with oxygen that releases heat and light, making it a valuable fuel source.
Biodegradability: As an organic material, wood is susceptible to decay by fungi and bacteria, which break down its polymeric structure.
Acidity: Wood is generally slightly acidic due to the presence of acetyl groups in hemicellulose and other acidic extractives.
4. What are some important applications of wood based on its chemical structure?
The chemical structure of wood dictates its primary applications:
Pulp and Paper Production: The high cellulose fibre content is the basis for the paper industry. Chemical pulping processes are used to separate cellulose fibres from lignin.
Fuel Source: The high carbon content in its organic polymers makes wood an effective source of energy through combustion.
Construction Material: The rigid composite structure formed by cellulose fibres embedded in a lignin matrix provides high tensile strength and compression resistance, making it ideal for building.
Chemical Feedstock: Wood can be chemically processed to produce derivatives like rayon, cellophane, and various chemicals like methanol and acetic acid through destructive distillation.
5. From a chemical standpoint, why does wood swell when it absorbs water?
Wood swells when it absorbs water due to its hygroscopic nature, which is a direct result of its chemical composition. The main components, cellulose and hemicellulose, are polysaccharides containing a large number of hydroxyl (-OH) groups. These groups are polar and readily form hydrogen bonds with water molecules. When exposed to moisture, water molecules penetrate the cell walls and bind to these hydroxyl sites, pushing the polymer chains apart and causing the wood to expand or swell.
6. Why is wood considered an anisotropic material?
Wood is considered an anisotropic material because its properties are direction-dependent. This is a direct consequence of its cellular structure and the orientation of its chemical components. The long, fibrous cellulose molecules are aligned primarily along the length of the tree trunk (the grain direction). As a result, wood exhibits its greatest strength and is most resistant to shrinkage and swelling along the grain, while its properties across the grain (radial and tangential directions) are significantly different and generally weaker.
7. How does the chemical component lignin contribute to the durability of wood?
Lignin plays a crucial role in the durability and decay resistance of wood. It is a complex, cross-linked aromatic polymer that acts as a natural binder, encrusting the cellulose and hemicellulose fibres. This encasement performs several functions: it provides structural rigidity and compression strength, but more importantly, it acts as a protective barrier. Lignin is highly resistant to chemical and biological degradation, making it difficult for enzymes from fungi and bacteria to access and break down the more susceptible cellulose and hemicellulose components, thereby enhancing the wood's overall durability.
8. What happens to the chemical structure of wood during combustion?
During combustion, wood undergoes a series of complex chemical transformations. Initially, as heat is applied, water evaporates. Then, a process called pyrolysis begins, where the heat breaks down the primary polymers (cellulose, hemicellulose, and lignin) into volatile gases (like carbon monoxide, methane) and a solid residue called charcoal (mostly carbon). These flammable gases then mix with oxygen in the air and ignite, producing flames, heat, and light. The remaining charcoal can also react with oxygen in a slower, glowing combustion reaction, eventually leaving behind ash, which consists of the inorganic mineral content of the wood.
9. What is the chemical difference between wood and an engineered product like particle board?
The primary chemical difference between natural wood and an engineered product like particle board lies in the presence of synthetic adhesives. Natural wood's structure is held together by its inherent components, mainly lignin. In contrast, particle board is manufactured by breaking wood down into small chips or particles and then bonding them back together under heat and pressure using a synthetic resin. Common resins include urea-formaldehyde (UF) or phenol-formaldehyde (PF). Therefore, particle board is a composite of natural wood particles and a synthetic polymer adhesive, which alters its chemical properties, such as its response to moisture and its emission of volatile organic compounds (VOCs).
