C1d Flashcards

1
Q

What is addition polymerisation?

A

-lots of alkenes opened up at the double bond and joined together to form polymer chains

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2
Q

What are polymers?

A

-formed when lots of monomers join together

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3
Q

What are the conditions needed for addition polymerisation?

A
  • high pressure

- catalyst

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4
Q

What do weak forces mean about a plastic?

A
  • chains are free to slide over each other

- plastic can be stretched easily and has a low melting point

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5
Q

What do strong forces mean about a plastic?

A
  • stronger bonds, possibly covalent bonds between chains
  • or cross-linking bridges
  • high melting point
  • plastics are rigid and can’t be stretched as the crosslinks hold the chains firmly together
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6
Q

What are some types of polymers?

A
  • strong, rigid (e.g.high density polyethene) used to make plastic milk bottles
  • light, stretchable (e.g.low density polyethene) used for shopping bags and squeezy bottles.Low melting point, so no good to carry very hot things
  • PVC is strong and durable, can be made either rigid or stretchy. Rigid used for window frames and piping, stretchy used to make synthetic leather
  • polystyrene foam used in packaging to protect breakable things, disposable coffee cups (thermal insulator, trapped air)
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7
Q

How is gore-tex made?

A

-laminating a thin film of expanded PTFE onto a layer of another fabric, e.g. nylon or polyester. Making PTFE sturdier

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8
Q

What are the advantages of gore-tex?

A
  • PTFE film has tiny holes which let water vapour through, so it is breathable
  • holes not big enough to let water droplets through and PTFE repels liquid water, so waterproof
  • great for outdoorsy types
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9
Q

What are the disadvantages of nylon?

A

-polyurethane coating doesn’t let water vapour pass through so sweat condenses -material is not breathable

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10
Q

Why is nylon used for clothing and how?

A
  • nylon is a synthetic polymer
  • not waterproof on its own
  • coat in polyurethane to make waterproof, tough and hard-wearing, and keep UV light out
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11
Q

Why do non-biodegradable plastics cause disposal problems?

A
  • landfill sites full up quickly and the plastics will still be there years later, a waste of land and plastic
  • burnt plastic releases acidic sulfur dioxide and poisonous hydrogen chloride, waste of plastic
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12
Q

What are chemists doing about non-biodegradable plastics?

A

-working on a variety of ideas to produce polymers that are biodegradable or dissolve

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13
Q

How to stop wasting plastics?

A
  • reuse them

- recycle. however sorting lots of different plastics for recycling is difficult and expensive

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