13.5 - Polymerisation in alkenes Flashcards
what are polymers?
polymers are long molecules made form thousands of repeat units of smaller molecules called monomers
what is addition polymerisation?
formation of a very long molecular chain (polymer) by repeated addition reactions of many unsaturated alkene molecules (monomers)
what is a repeat unit?
specific arrangement of atoms that occurs in the structure over and over again.
repeat unit written in square bracket with n on outside.
how is poly(ethane) made?
heating a large number of ethene monomers at high pressure.
what is poly(ethene) used for?
supermarket bags, shampoo bottles
what is poly(choloroethene)?
PVC
made of many chloroethene monomers.
used in pipes and insulation
what is poly(tetrafluoroethene)?
Teflon
Used in non-stick pans
Made of many tetraflouroethene monomers
why are polymers non-biodegradable?
they are very unreactive
what is the issue with recycling PVC?
PVC has high chlorine content (poly(chloroethene))
Dumping PVC not sustainable, and when burnt, PVC releases HCl, which is a corrosive gas.
What can we do with polymers once used?
Recycle them
Burn for fuel
Feedstock recycling
what is feedstock recycling?
feedstock recycling is where chemical and thermal processes can reclaim monomers, gases or oil from waste polymers.
the products from feedstock recycling can resemble those produced from crude oil in refineries.
these materials can be used in raw materials to produce new polymers.
what are bioplastics?
bioplastics produced from plant starch, cellulose etc.
offer a sustainable and renewable alternative to oil-based products.
what are biodegradable polymers?
biodegradable polymers can be broken down by microorganisms into water, CO2 and biological compounds.
made from starch or cellulose.
compostable polymers containing poly(lactic acid) are becoming more popular.
what are photodegradable polymers?
oil-based polymers that contain bonds that are weakened when absorbing light to start degradation.
