Polymer Science and Industrial Material Properties

Fundamental Definitions of Polymers

Monomers: Individual molecules with double or triple bonds. Polymer: The binding of several monomers. Homopolymers: A set of monomers of the same type. Copolymers: A set of monomers of different kinds.

The Polymerization Process

The process of obtaining a molecule that forms a chain is called polymerization.

• Polyaddition: Monomers react with each other and unite to form a chain.
• Polycondensation: A chemical reaction occurs between two chemical products, which then polymerize.
• Polymerization degree: The number of monomers contained in the molecular segment.

Classification of Polymers by Origin

Organic polymers can have different origins:

• Natural: These occur spontaneously in natural products, such as cellulose and rubber.
• Artificial: Obtained industrially through the modification of natural polymers, such as celluloid.
• Synthetics: Industrially obtained from their basic chemical components, such as polyethylene and PVC.

Difference Between Artificial and Synthetic Polymers

Artificial polymers are obtained industrially through the modification of natural polymers, while synthetic polymers are obtained industrially from their elemental components.

Molecular Structures and Properties

Polymers can have various molecular structures:

• Linear and branched: These form thermoplastics.
• Cross-linked: These form elastomers.
• Lattice: These are always thermosetting (thermostable).

Functions of lubricants: To improve the sliding of surfaces and reduce friction problems.

Industrial Materials: Ceramics and Glass

Hardening Processes of Clay and Cement

• Clay: The drying phase uses hot air at temperatures between 700-1400°C.
• Cement: Produced by a complex chemical reaction of the material with water.

Differences Between Clay and Porcelain

Clay is easily found in nature; when water is added, it becomes plastic. Porcelain is a clay derivative used for dental protections and insulators.

Effects of Tempering and Annealing on Glass

• Annealing: Heating to a temperature lower than the melting point followed by slow cooling so the glass does not break.
• Tempering: Heating and rapid cooling to a suitable temperature to make the glass more resistant.

Composite Materials and Concrete

Composites: Formed by two or more materials of different shapes and sizes without a chemical combination between them.

• Concrete: A composite made of cement and high-grade sand; it has high compression resistance but low tensile resistance.
• Reinforced concrete: Made with steel bars or mesh.
• Prestressed concrete: Steel bars are placed under tension, making the material highly resistant.

Advanced Composite Fabrication Techniques

Plywood and sandwich panels (empovedat) are two techniques for creating composite materials with the common goal of obtaining light, stiff, and resistant materials.

• Plywood: Lightweight and resistant.
• Sandwich panels (empovedat): Rigid, resistant, and light.