13.5 Polymerisation in alkenes

define repeat unit

the specific arrangement of atoms in the polymer molecule that repeats over and over again

molecular formula of propene

C₃H₆

uses of propene

children’s toys, packing crates, guttering, uPVC windows, fibre for ropes

molecular formula of phenylethenestyrene

C₈H₈

molecular formula of tetrafluoroethene

C₂F₄

name an environmental issue with the use of alkene based polymers

non-biodegradable

disadvantage of recycling polymers

discarded polymers have to be sorted by type

disadvantage of PVC recycling

PVC releases hydrogen chloride when burnt which is a corrosive gas

why are some polymers difficult to recycle

some polymers are derived from petroleum or natural gas which means it has a high stored energy value

steps of using waste polymers as fuel

1) waste polymers are incinerated

2) this produces heat

3) this heat generates steam

4) this steam drives a turbine which produces electricity

define feedstock recycling

the chemical and thermal processes that can reclaim monomers, gases, or oil from waste polymers

advantage of feedstock recycling

able to handle unsorted and unwashed polymers

define bioplastics

plastics produced from plant starch, cellulose, plant oils, and proteins that offer a renewable and sustainable alternative to oil based products

define compostable polymers

polymers based on poly(lactic acid) which degrade and leave no visible or toxic residues

define photodegradable polymer

polymer which degrades by absorbing UV