GCSE: OCR gateway: C1: Designer polymers + Cooking and food additives

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  • C1
    • Designer Polymers
      • Breathable polymers
        • Nylon is: tough, lightweight, keeps water out ,and UV light out
          • It does not let water vapour through so  sweat condenses and makes the wearer wet and cold in their jacket
        • Gore tex has the properties of nylon and is also breathable as water vapour can pass through the membrane but rainwater cannot
          • The holes in the PTFE are too small for water droplets to pass through however large enough to let water vapour through
          • PTFE membrane is too fragile on its own so it is laminated onto nylon to produce a stronger fabric
      • Disposing of polymers
        • New types of polymers: polymers that dissolve + biodegradable polymers
        • Issues with existing polymers
          • Non-biodegradable polymers fill up landfill sites quickly
            • Waste of crude oil
          • Waste of land
          • Burning makes toxic gases
          • Hard to sort polymers so recycling difficult
      • Stretchy + ridged polymers
        • Held together by strong covalent bonds
        • Plastics with weak intermolecular forces between polymer molecules
          • Have low melting points
          • Can be stretched easily as polymer molecules slide over one another
        • Plastics with strong forces between polymer molecules
          • High melting points
          • Cannot be stretched and are ridged
    • Cooking and Food Additives
      • Proteins and carbohydrates
        • Protein molecules permanently change shape when cooked
          • Known as DENATURING
          • Texture of protein food changes as the shapes of the protein molecules change perminently
        • Potato is a carbohydrate which is easier to digest when cooked
          • Starch grain swell up and spread out
          • Cell walls rupture so they do not have a ridged structure and there is a softer texture
      • Baking powder
        • Sodium hydrogen carbonate = sodium carbonate + carbon dioxide + water
          • 2NaHCO3 = Na2CO3 + CO2 + H2O
      • Emulsifiers
        • Have water loving head + water hating tail
          • water loving = hydrophilic
          • water hating = hydrophobic
        • Emulsifiers are used to stop water and oil from separating
          • Hydrophilic end bonds to water molecules
          • Hydrophobic end binds to fat/oil molecules
          • Hydrophilic end attracted to water molecules which surround oil keeping them together


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