Using alkenes to make polymers

Using alkenes to make polymers

1. alkenes can be used to make polymers through polymerisation - meaning joining many small alkene molecules(monomers) to form larger molecules - long chain molecules(polymers)

   • E.G many ethene molecules joined together makes polyethene
   • monomers are unsaturated - polymers are saturated
   • different polymers means different physical properties
     • depending on what it's made from
       • polymers physical properties also depend on temperature and pressure of polymerisation higher temperature and higher pressure means less dense and more flexible
     • making them suitable for many different uses
       • light, stretchable polymers E.G (low density) polyethene is used for plastic bags - Elastic polymer fibres are used for stretchy LYCRA fibres for tights
       • new uses are always developed. Waterproof coatings for fabrics are made from polymers and dental polymers are used in resin tooth fillings - polymer hydrogel wound dressings keep wounds moist
         • biodegradable packaging materials made from polymers and cornstarch are being produced
           • memory farm is a smart material - it's a polymer which gets softer as it warms up and can be used to make mattresses

2. Polymers are cheap - however most are non-biodegradable

   • not broken down by microorganisms
     • difficult to get rid of polymers so it's best to reuse them as many times as possible then recycle
       • things made of polymers are usually cheaper than metal objects however as crude oil gets used up it's price will rise so crude oil products E.G polymers will be more expensive