tech

• What are plastics primarily made from?

  Plastics are primarily made from natural substances such as oils, insects, and plants.
• What are synthetic plastics?

  Synthetic plastics are man-made materials derived from natural substances.
• What are monomers?

  Monomers are smaller molecules that are joined together to form polymers.
• What is polymerization?

  Polymerization is the process of joining thousands of monomers to form polymers.
• What are the two main types of plastics?

  • Thermoplastics
  • Thermosetting Plastics
• What are the characteristics of thermoplastics?

  Thermoplastics can be re-heated, re-shaped, and recycled.
• At what temperature range can most thermoplastics be thermoformed?

  Thermoplastics can be thermoformed at temperatures around 70-260°C.
• How do thermoplastics behave when heated?

  The molecules of thermoplastics move apart when heated and return to their original position when cooled.
• Why are thermoplastics preferred for certain applications over thermosetting plastics?

  Thermoplastics are preferred for their versatility and ability to be reshaped multiple times.
• What is a key characteristic of thermosetting plastics?

  Thermosetting plastics can only be heated and shaped once.
• What happens to the molecules in thermosetting plastics once they are formed?

  The molecules in thermosetting plastics become interlinked and cannot be re-heated or reshaped.
• What are some common applications of thermosetting plastics?

  Thermosetting plastics are used for products like saucepan handles and electrical fittings.
• What are some examples of thermoplastics?

  • Acrylic
  • Polyvinyl chloride (PVC)
  • Acrylonitrile Butadiene Styrene (ABS)
  • Nylon
• What is acrylic commonly used for?

  Acrylic is often used for display signs and is available in a wide range of colors.
• How does acrylic compare to glass in terms of impact resistance?

  Acrylic is ten times more impact resistant than glass.
• At what temperature can acrylic be thermoformed?

  Acrylic can be thermoformed at 100°C.
• What are the two forms of PVC?

  PVC comes in soft and flexible (plasticised) and hard and rigid (unplasticised) forms.
• Why is PVC less common in school workshops?

  PVC can give off toxic gases when being thermoformed.
• What is ABS known for?

  ABS is known for being a tough, hard, and durable alternative to acrylic.
• What are the advantages of nylon?

  Nylon is strong, self-lubricating, and has a high melting point of 220°C.
• What are some examples of thermosetting plastics?

  Examples of thermosetting plastics include melamine, polyester resin, epoxy resin, and urea formaldehyde.
• What is melamine used for?

  Melamine is used for kitchenware and tableware due to its durability and heat resistance.
• How does polyester resin contribute to the marine industry?

  Polyester resin is widely used in building boats due to its strength and resistance to water absorption.
• What are the advantages of epoxy resin over polyester resin?

  Epoxy resin has greater toughness, strength, and resistance to moisture and fatigue.
• What is urea formaldehyde commonly used for?

  Urea formaldehyde is used as an adhesive and binding agent for plywood and MDF.
• What are the properties and applications of melamine?

  Properties:

  • Very hard and durable
  • Heat resistant
  • Food hygienic
  • Easy to clean

  
  

  Applications:

  • Kitchen worktops
  • Tableware
  • Flame retardant products
• What are the properties and applications of polyester resin?

  Properties:

  • Strong, stiff, and tough
  • Good resistance to water absorption

  
  

  Applications:

  • Boat building
  • Canoes
  • Yachts
• What are the properties and applications of epoxy resin?

  Properties:

  • Excellent adhesive properties
  • Strong, hard, and tough
  • Good electrical insulator

  
  

  Applications:

  • Aerospace industry
  • Paints and protective coatings
• What are the properties and applications of urea formaldehyde?

  Properties:

  • Stiff and non-transparent
  • Excellent tensile strength
  • Good electrical insulator

  
  

  Applications:

  • Electrical sockets
  • Adhesives
  • Binding agent for plywood and MDF
• What are the two classifications of metals?

  Metals are classified as ferrous and non-ferrous.
• What is the main difference between ferrous and non-ferrous metals?

  Ferrous metals contain iron, while non-ferrous metals do not contain iron.
• Why do ferrous metals need protection against corrosion?

  Ferrous metals tend to corrode and rust when exposed to the weather.
• What are pure metals?

  Pure metals contain only one type of metal and are not mixed with any other metals.
• What are alloys?

  Alloys are mixtures of two or more pure metals.
• Why are alloys often preferred over pure metals?

  Alloys tend to have better strength properties than pure metals.
• What is a characteristic of pure metals in terms of conductivity?

  Pure metals often have better electrical conductivity than alloys.
• What happens to ferrous metals when exposed to moisture?

  Ferrous metals tend to rust when exposed to moisture.
• How are metals classified?

  Metals are classified as either ferrous or nonferrous.
• What distinguishes ferrous metals from nonferrous metals?

  Ferrous metals contain iron, while nonferrous metals do not contain iron.
• Why do ferrous metals need protection against corrosion?

  Ferrous metals tend to corrode and therefore need some form of protection against corrosion.