Topic 10 (Using recourses) Flashcards
What are ceramics?
Ceramics are non-metal solids with high melting points that are not made from carbon-based compounds.
What is the matrix or binder in a composite?
The material that surrounds and binds together the reinforcement material.
Give examples of composite materials.
Fibreglass (glass + polymer), carbon fibre (carbon + polymer), concrete (sand + gravel + cement), and wood (natural composite of cellulose fibres + lignin).
Why are composites useful?
They are strong, lightweight, and resistant to corrosion and wear.
What are polymers?
Long chains of repeating monomer units made by polymerisation, usually from alkenes.
What do the conditions of a Polymer rely on
Depends both on the monomers and conditions used to make polymer
How do we change property of a polymer using conditions
- Change temperature in reaction
- Change the pressure in reaction
- Different Catalyst
What happens when thermosoftening polymers are heated and cooled?
-Thermosoftening polymers melt when we heat them
- We can reshape them while they are soft
- They then go back to a solid when we cool them down
What happens to the intermolecular forces (IMFs) in thermosoftening polymers when they are heated and cooled?
: When heated, the intermolecular forces break, causing the polymer strands to separate and melt. Upon cooling, the intermolecular forces reform, and the polymer solidifies, allowing it to be reshaped.
What are the key differences between thermosetting and thermosoftening polymers?
Thermosoftening polymers melt when heated and can be reshaped; they solidify again when cooled.
Thermosetting polymers do not melt upon heating; they remain rigid due to strong cross-links between polymer chains.
Why do thermosetting polymers not melt when heated?
The strong cross-links between the polymer chains are not broken by heat, which is why thermosetting polymers do not melt.
What is meant by the word corrosion
Corrosion is the destruction of materials by chemical reactions with substances in the environment
Conditions required for rusting
Rusting occurs when iron (or steel) is exposed to both oxygen and water (moisture).
Name methods to prevent corrosion
Barrier methods (e.g. paint, oil, grease)
Galvanizing
Sacrificial protection
Coating with plastic
Electroplating
Cathodic protection
How can you carry out an experiment to investigate the conditions required for rusting?
Materials: Iron nails, test tubes, water, oil, and a drying agent (e.g., anhydrous calcium chloride).
Set-up:
Test tube 1: Place an iron nail and add water (with oxygen in the air). Leave it open to air.
Test tube 2: Place an iron nail, add water, but seal the tube to prevent oxygen from entering.
Test tube 3: Place an iron nail, and add oil to prevent moisture (water) from contacting the nail.
Test tube 4: Place an iron nail in dry conditions with a drying agent (to remove moisture) and no water.
Observation: After a few days, check the nails for signs of rusting (red-brown color). Rusting should only occur in the test tube with both water and oxygen.
What is the barrier method
The barrier method involves coating a metal with a protective layer to prevent contact with oxygen and moisture, which causes rusting.
e.g grease, paint, electropainting
What is electro painting and how does it work?
Electro painting is a process where electrically charged paint particles are applied to a metal surface. The metal is made positively charged, while the paint particles are negatively charged. The metal attracts the paint, which is deposited evenly, creating a smooth and durable coating.
What is galvanising and how does it stop corrosion?
Galvanising is the process of coating iron or steel with a layer of zinc. The zinc acts as a barrier to protect the metal from moisture and oxygen, preventing corrosion. Additionally, if the zinc layer is scratched, it still offers protection by acting as a sacrificial anode, corroding before the iron or steel.
What is sacrificial protection?
Sacrificial protection involves attaching a more reactive metal (like zinc or magnesium) to a less reactive metal (like iron or steel). The reactive metal corrodes first, protecting the less reactive metal from corrosion.
What is the difference between reusing and recycling materials?
Reusing involves using an item again for the same or similar purpose, while recycling involves processing materials to create new products.
Why is recycling important for sustainable development?
Recycling helps reduce the need for raw materials, conserves energy, reduces landfill waste, and lowers environmental pollution.
What are some environmental benefits of recycling?
Recycling reduces energy consumption, raw material extraction, and pollution while conserving natural resources and reducing landfill waste.
How does recycling reduce the impact on the environment?
Recycling reduces the need for new raw materials, cuts down on energy use, and minimizes pollution from mining and processing materials.
What is the role of the recycling symbol on materials?
The recycling symbol indicates that a material is recyclable and can be processed to create new products, promoting the recycling of waste.
