Industrial Materials: Plastics, Wood, and Ceramics

Classification and Types of Plastics

Thermoplastics: These materials can be molded easily when heated.
Thermosets: Once set, these materials do not regain their molded shape even when reheated.
Elastomers: These are materials characterized by an elastic structure.

Common Plastic Families and Applications

• PC (Polycarbonate): Used in cameras, windows, and helmets.
• PVC (Polyvinyl Chloride): Used for pipes, windows, vinyl, cable sheathing, and syringes.
• PP (Polypropylene): Found in bags, bottles, and small appliances.
• PE (Polyethylene): Used for boxes, toys, bottles, pipes, and bags.
• PMMA (Acrylic): Used in car light covers, bathroom accessories, glasses, and glazing for boats and planes.
• PS (Polystyrene): Used for car interiors, tapes, ribbons, and egg cartons.
• ABS: Used for car casings, computers, and toys.
• PF (Phenol Formaldehyde): Used in motor housings and mobile switches.
• UF (Urea-Formaldehyde): Used for countertops, chairs, tables, and furniture.
• MF (Melamine-Formaldehyde): Commonly used for chairs.
• UP (Unsaturated Polyester): Used for aircraft coatings and ships.
• EP (Epoxy Resin): Used in printed circuits.
• PUR (Polyurethane): Used for sponge mattresses.

Wood Anatomy and Woodworking Processes

Parts of Wood

The primary components of wood include the heartwood, sapwood (wood), outer bark, inner bark, and cambium.

The Woodworking Cycle

1. Debarking: Trunks pass through rollers to tear away the bark.
2. Parting: This involves cutting the pieces to specific lengths using circular saws.
3. Sawing: The mission is to obtain planks and boards.
4. Drying: Before use, planks and boards must have their moisture content reduced, either naturally or in outdoor kilns.
5. Planing (Brushing): This aims to eliminate irregularities and improve the appearance of the wood.

Wood Derivatives and Engineered Wood

• Chipboard: Wood chips and sawdust are mixed with glue, compressed, and dried.
• Veneer (Chapado): Thin sticks or sheets of wood.
• Plywood: A wooden base plate layered on both sides.
• Hardboard (TableX): Created from wood fibers under high pressure and temperature.
• MDF (DM): Wood fibers where lignin is removed and resin is added.

Paper, Cardboard, and Ceramic Materials

Porous Ceramics

• Porous Clay: Cooked clay.
• Italian Loza: Cheaper tableware.
• English Earthenware: Used for decorative objects.
• Refractories: Such as refractory bricks.

Waterproof Ceramics

• Common Stoneware: Used for floors and walls.
• Fine Stoneware: Used for dinnerware and tiles.
• Porcelain: Used for luxury sculptures.

Construction Materials: Gypsum and Cement

Cast Gypsum

This is a white material obtained from calcium sulfate dihydrate.

Production: The raw material is calcined at 450°C to remove water, then ground and packaged. To use it, water is added back to the mixture.

Cement Derivatives and Concrete

• Mortar: A mixture of cement powder with sand and water.
• Concrete: A mixture of cement powder, sand, water, and gravel used in construction. It has great compressive strength but little traction.
• Reinforced Concrete: Steel bars are introduced into the mass of concrete. The steel supports traction efforts while the concrete handles compression.
• Prestressed Concrete: A type of reinforced concrete whose bars have been subjected to tension while the concrete is setting.