Ch 20 - (Petrochemicals)

• Large molecules built by linking 50 or more smaller molecules called monomers • repeat unit is connected to adjacent unit via covalent bonds

PVC and nylon

Addition polymerization of ethene monomers

• Addition of many monomers to make a long chained polymer • Many ethene monomers join together due to carbon carbon double bond breaking (C = C)

• Joins up many monomers with (C = C) bond • one of the bonds in C=C breaks and forms a bond with the adjacent monomer • polymer contains single bonds

• Addition of alkene monomers • alkene monomers with different atoms attached to the monomer such as chlorine or a hydroxyl group.

• name of the monomer in bracket • adding poly - as prefix • If propene is the alkene monomer used, same is poly (propene) • poly ethene formed by addition of polymerization of ethene monomers

Very large compared to most molecules

repeat units

• change the double bond in monomer to a single bond • add a continuation bond to each end of repeat unit • bonds on either side of polymer must be extended outside the brackets (called extensions or continuation bonds) • small subscript n is written on bottom right hand side to indicate large number of repeat units • Add on rest of the group in same order

• identify the repeating unit polymer • change single bond in repeat unit to a double bond in monomer • remove bond from each end of repeat unit

2 different monomers are linked together with the removal of a small molecule, usually water

• addition polymerization forms the polymer molecule only • condensation polymerization forms the polymer molecule and one water molecule per linkage

• 2 functional groups, one on each end • each monomer react with another end of monomer, creating a long chain of monomers

• polyamide made from dicarboxylic acid (carboxylic with COOH group on either side) • diamines (an amine with NH2 group at either end)

Each COOH group reacts with another NH2 group on other monomers

formed with a subsequent loss of one water molecule per link

drawing out the polymer using boxes to represent the carbon chain

• polyethylene terephthalate • polyester made up of dicarboxylic acid monomers (COOH group at either end) and diols (alcohols with OH group at either end)

each COOH group reacts with another OH group on another monomer

• subsequent loss of one water molecule per link • every ester linkage formed in condensation polymerization, one molecule of water is formed from the combination of a proton (H+) and hydroxyl ion (OH-)

synthetic fibres sold under terylene

drawing out polymer using boxes to represent carbon chain

• Polymer • chemically uncreative (non - biodegradable)