Lecture - 37 A general account of Wood Conversion Products: Paper, Rayon, Plastic, Cork
A general account of Wood Conversion Products: Paper, Rayon, Plastic, Cork:-
1. Paper:-
Source:-Made from cellulose fibers primarily extracted from wood pulp of softwood trees (e.g., Pinus, Spruce, Fir) and some hardwoods (Eucalyptus, Populus).
Non-wood sources:- Bamboo, cotton rags, bagasse (sugarcane waste), etc.
Process:-
Pulping:- Mechanical or chemical methods to extract cellulose from wood.
Bleaching:- To remove lignin and whiten the pulp.
Sheet Formation:- The pulp is spread on wire mesh, dried, and pressed into sheets.
Finishing:- Sizing, coating, calendaring, and cutting into required sizes.
Uses:-
> Writing and printing paper
> Newsprint and books
> Packaging materials (cartons, corrugated boards)
> Tissue paper, napkins
> Industrial use in filtration, insulation
> Stationery items
> Wrapping and decorative paper
> Paperboard and cardboards
> Currency paper (with cotton fibers)
> Eco-friendly disposables
2. Rayon (Artificial Silk):-
Source:- Derived from cellulose obtained from wood pulp, especially from trees like Spruce, Pine, and Hemlock.
Process (Viscose Process – most common):-
> Cellulose is treated with sodium hydroxide to form alkali cellulose.
> Reacted with carbon disulfide → viscose solution.
> Extruded through spinnerets into an acid bath → solidifies into fibers.
Types:-
i. Viscose rayon
ii. Modal
iii. Lyocell (eco-friendly variant)
Uses:-
> Textile industry – clothing, sarees, linings
> Home furnishings – curtains, bedsheets
> Blended with cotton or wool
> Used in tire cords (high-tenacity rayon)
> Surgical dressings and hygiene products
> Artificial silk imitation
> Reinforcement in rubber goods
> Absorbent items – wipes, sponges
> Non-woven fabrics
> Feminine hygiene and baby products
3. Plastics (from Wood-derived Cellulose):-
Source:-
> Derived from cellulose extracted from wood, especially for early bioplastics like celluloid, cellulose acetate, and rayon.
> Synthetic plastics today are mostly petroleum-based, but bioplastics are making a comeback.
Early Bioplastics:-
i. Celluloid (from nitrocellulose) – used in film reels, combs.
ii. Cellulose acetate – used in eyeglass frames, pens.
Modern Uses:-
> Packaging materials (biodegradable plastics)
> Electrical insulation
> Optical films and photographic films
> Eyewear, buttons, combs
> Toys and novelty items
> Film industry (historically)
> Coatings and laminates
> Moulded items and furniture
> Aerospace and automotive parts
> Environmentally friendly disposable items
4. Cork:-
Source:-
> Harvested from the bark of the Cork Oak (Quercus suber), mainly grown in Mediterranean countries like Portugal, Spain, and parts of North Africa.
> Sustainable harvest – bark regenerates every 9–12 years.
Processing:-
> Bark is stripped and seasoned.
> Boiled and flattened.
> Cut, punched, or ground to make various cork products.
Uses:-
> Bottle stoppers (especially for wine)
> Flooring and wall tiles
> Thermal and sound insulation
> Gaskets and seals
> Corkboards and memo boards
> Life jackets and buoys (due to buoyancy)
> Shoe soles and sandals
> Craft items and decorations
> Sports equipment (cricket balls, shuttlecocks)
> Cushioning and packing material
