Types of Plastics, Fibers, and Construction Materials

Plastics

Plastics are materials composed of polymers, consisting of long chains of atoms that contain carbon.

Types of Plastics

• Natural Plastics: Directly obtained from vegetable raw materials (cellulose and cellophane, latex) or animal (casein).
• Synthetic or Artificial Plastics: Made from compounds derived from petroleum, natural gas, or coal.

Industrial processing of these raw materials and compounds is called polymerization.

During the production of plastics, fillers are added (materials such as glass fiber, textile fibers, silica, paper, filler, or sawdust). Some additives (chemicals) are also incorporated.

As we have seen, properties such as elasticity, rigidity, toughness, and flexibility are specific to certain plastics.

Most plastics are not biodegradable, and to eliminate them, incineration is often used.

Biodegradable plastics decompose naturally through the action of certain bacteria or biological agents.

Plastic materials can also undergo a recycling process.

• Chemical Recycling: Consists of recovering the original constituents to obtain new materials.
• Mechanical Recycling: With this process, materials are crushed until granules are obtained to produce a new plastic.

Classification of Plastics Based on Molecular Structure

• Thermoplastic Plastics: Obtained from petroleum compounds, they comprise weakly linked chains.
• Thermosetting Plastics: Derived from petroleum compounds, they are formed by chains strongly linked in different directions.
• Elastomers: Obtained through vulcanization, chains are formed laterally and joined together.

Fibers

Fibers are extracted from natural raw materials of plant, animal, or mineral origin.

• Cotton: Comes from the fruit of this plant of the mallow family.
• Linen: Obtained from the stem of the plant of the same name, of the linaceae family.
• Esparto: Extracted from the leaves of herbaceous plants.
• Wool: Comes mainly from sheep.
• Silk: A liquid substance secreted by a silkworm.
• Asbestos: A mineral with a fibrous structure.
• Metals: Some metals, like gold, silver, and copper, can be made into fibers.

Synthetic fibers such as nylon, polyester, rayon, and lycra are plastics.

Stone Materials

Stone materials are obtained from rocks. They are found in nature and constitute large blocks and slabs.

• Marble and Granite: Two rocks characterized by high density, cold touch, great hardness, resistance to environmental conditions, and compressive strength.
• Slate: A hard, dense, compact, and waterproof material.
• Stone for Sculpture, Sands, and Gravels: Used especially as aggregate material that is fragmented.

Other Construction Materials

• Gypsum: Obtained from plaster or gypsum stone, pureed and cooked until dehydrated, then treated further.
• Cement: Obtained from a mixture of limestone and clay, finely ground and baked.
• Mortar: A binder material formed from sand and cement.
• Concrete: A mixture of water, sand, gravel, and cement that hardens over time.
• Glass: A transparent or translucent material that can acquire different qualities of color.

Ceramic Materials

Ceramic materials are obtained from clayey raw materials.

• Baked Clay: Made with matte reddish ordinary clay.
• Stoneware: Obtained from a mixture of white clay with silica.
• Porcelain: Made from a very select white clay called kaolin.