Polymers

Polypeptides - found in proteins Polyamides - formed from diamines and dicarboxylic acids Polyesters - formed from diol and dicarboxylic acid

2 different monomers with at least 2 functional groups react together, eliminating a water molecule A link is made, which determines the type of polymer produced

Kevlar -made from benzene-1,4-dicarboxylic acid and 1,4-diaminobenzene -used in bulletproof vests, car tyres and some sports equipment -lightweight but strong Nylon 6,6 -made from hexanedioic acid and 1,6-diaminohexane -used in ropes, carpets, clothing and parachute fabric

Terylene (PET) -made from benzene-1,4-dicarboxylic acid and ethane-1,2-diol -used in plastic drinks bottles, sheeting and clothes

Hydrolysis

-have polar bonds (C-O and C-N) -usually more rigid and stronger than in addition polymers -hydrogen bonds exist between polymer chains, as well as dipole-dipole and Van der Waals forces -makes condensation polymers stronger than addition polymers

-made from monomer units -uses include plastic bottles, digital technology, non-stick coatings on pans, etc -condensation polymers are polar = susceptible to attack from nucleophiles -hence biodegradable and hydrolysis slowly breaks them down -polyalkenes are saturated addition polymers -normally non-polar, so don’t degrade well

-are too difficult to recycle -are too difficult to separate from other materials -there is not enough of to extract to make it economically viable

-produces methane (greenhouse gas) -also water contamination from waste leaching -hence landfill is not very sustainable -very expensive so there is a need to reduce reliance on -large amounts of land needed

-burning waste plastics that can’t be recycled -energy from burning can be used to generate electricity -significantly reduces volume of rubbish -however, CO2 produced (GHG) -release toxic fumes -e.g. PVC produces acidic HCl gas -flue gas scrubbers are used to neutralise it by firing a base at it

-most plastics are made from crude oil (non-renewable) -reduces dependency on crude oil -some plastics can be re-moulded into new objects -others can be cracked into monomers which can be used as organic feedstock for plastics or other substances Pros: -reduces reliance on landfill -preserves non-renewable raw materials, e.g. crude oil -cheaper to recycle than make plastics from scratch -less CO2 is produced than incinerating Cons: -plastics can be contaminated with other materials -difficult to recycle due to wide variety of different plastics -difficult to re-make original plastic from recycled material -sorting and processing plastics to be recycled is more expensive than incineration