2_Polymers_-_uses_for_plastics

Introduction

  • Name and form: Miss Denby, Room R/HAM.

Polymers - Plastic Uses

  • Learning Objectives (LO):

    • To describe how polymers can be categorised.

  • Success Criteria (SC):

    1. Explain what a polymer is.

    2. Explain the difference between natural and synthetic and identify examples of each.

    3. State how polyethene, polypropene, and polystyrene differ.

Overview of Polymers

  • Definition:

    • Polymers are very large molecules made from monomers (smaller molecules).

  • Common Examples: Polyethene, Polypropene, Polystyrene.

  • Applications:

    • Plastic products, water-saving hydrogels, encapsulated microbes, waterproof coatings.

  • Recycling Information:

    • Identification of plastic types and recycling processes.

  • Environmental Impact:

    • Many polymers are non-biodegradable, leading to waste disposal and recycling challenges.

Classification of Plastics

  • Types of Plastics:

    • Thermoplastics:

      • Can be reheated and reshaped multiple times.

    • Thermosetting Plastics:

      • Can only be heated and shaped once, making them difficult to recycle.

Thermoplastics

  • Properties and Advantages:

    • Lightweight.

    • Can withstand high temperatures and act as good insulators.

    • High strength, low cost, energy-efficient in manufacturing.

  • Disadvantages:

    • May melt in high UV levels.

    • Poor resistance to hydrocarbons and solvents.

    • Tend to break under high stress instead of deforming.

Examples of Thermoplastics

  • Acrylic:

    • Commonly used in educational materials.

    • Versatile: shiny finish for shop signs, bath tubs, bone cement, eye lenses.

  • Polyvinyl Chloride (PVC):

    • Light, tough, easy to shape, resistant to acids/bases.

    • Commonly used for pipes, window frames, and containers.

  • High Impact Polystyrene (HIPS):

    • Commonly used in vacuum forming.

    • Lightweight, hard, stiff, used in toys.

Other Thermoplastics

  • Examples include: Nylon, Polyethene, Polypropylene, Polystyrene, Teflon.

Thermosetting Plastics

  • Properties:

    • Once shaped, cannot be remolded.

    • Scratch-resistant, good electrical insulators, light, and tough.

  • Examples:

    • Epoxy:

      • Water and heat resistant.

    • Urea Formaldehyde:

      • Strong, electrical insulator, used in plugs/sockets.

    • Phenol Formaldehyde:

      • Made for hard, strong products like saucepan handles and electrical fittings.

Other Uses of Thermosetting Plastics

  • Applications:

    • Rubbers, adhesives, gloves, erasers, baking molds, balloons, insulation of cables.

  • Additional examples: Bakelite, Polyester, Silicone, Melamine.

Differences Between Thermoplastics and Thermosetting Plastics

  • Thermoplastics:

    • Can be reheated and reshaped.

  • Thermosetting Plastics:

    • Once molded, they cannot be reshaped, making recycling challenging.

Conclusion

  • Activity:

    • Complete the associated worksheet to reinforce understanding of the material.