alkenes + addition polymerisation

what is an alkene?

an unsaturated hydrocarbon - C=C double bond is an area of high e^- density

what is a polymer?

long chain molecule made from lots of small molecules (monomers) joined together

what is a monomer?

small molecules that join together to make polymers

what is addition polymerisation?

formation of long chain molecules from lots of small molecules joining together w/ no other products

draw the monomer structure of poly(ethene):

draw the polymer structure of poly(ethene):

draw the repeating unit of poly(ethene) and name the bonds at either end of the repeating unit:

trailing bonds

how do we name addition polymers?

poly(name of alkene)

what are addition polymers formed from?

alkenes and substituted alkenes

describe the properties of addition polymers:

• unreactive

• chains usually non-polar so held together by VDWs

• the longer the polymer chains are/the closer together the chains can get, the stronger the VDWs between the chains will be

• polyalkenes made up of long, straight chains → strong and rigid

• polyalkenes made up of short, branched chains → weaker and flexible

what is poly(chloroethene)/PVC and what can it be used for?

• polymer of chloroethene

• has long, closely packed polymer chains - hard, but brittle at room temp

• rigid PVC - drainpipes and window frames

how can we modify PVC’s properties?

• by adding a plasticiser - pushes polymer chains apart, reducing strength of VDWs

• this means the polymer can slide around more, making it easier to bend

• plasticised PVC - electric cable insulation, flooring tiles, clothes