polymers

when an unsaturated monomers react to form a polymer monomers contain C=C bonds chains form when same basic unit is repeated over and over

due to strong C-C and C-H bonds and non-polar nature of the bonds and therefore are non-biodegradable

there are two different monomers that add together, and a small molecule is usually given off as a side-product eg H2O or HCl the monomers usually have the same functional group on both ends of the molecule eg di-amine di-carboxylic acid

carboxylic acid + alcohol –> ester + water acyl chloride + alcohol –> ester + HCl

carboxylic acid + amine –> amide + water acyl chloride + amine –> amide + HCl

using the carboxylic acid would need an acid catalyst and would only give an equilibrium mixture the more reactive acyl chloride goes to completion and does not need a catalyst, but does produce hazardous fumes of HCl

hydroxycarboxylic acid monomer, just need 2 to react together

a common polyester used in clothing, tire cords formed from benzene-1,4-dicarboxylic acid and ethane-1,2-diol

a common polyamide 6,6 stands for 6 carbons in each of the monomers used in textile fibres it is formed via reaction between hexanedioic acid and hexane-1,6-diamine

polyamide used in bulletproof vests

permanent dipole- permanent dipole forces between the C=O groups in the different chains also VDW between chains

hydrogen bonding between the oxygen in C=O and the H in N-H groups in different chains also VDW forces polyamides will therefore have higher melting points than polyesters

presence of polar bonds which can attract attacking species such as nucleophiles and acids

by hydrolysis by acid or alkali this hydrolysis will result in original monomers forming- although the carboxylic acid or amine group will be in salt form depending on whether the conditions are acidic or alkaline this means they are BIODEGRADEABLE

-most common method of disposal of waste in UK -many are now reaching capacity -european regulations will mean councils charged much more for using landfill -most polymers (polyalkenes) are non-biodegradable and take many years to break down -could use more biodegradable plastics eg polyamides ad cellulose and starch based polymers to improve rates of decomposition

rubbish is burnt and energy produced is used to generate electricity some toxins can be released on incineration modern incinerators can burn more efficiently and most toxins and pollutants can be removed greenhouse gases will still be emitted though volume of rubbish greatly reduced

saves raw materials- nearly all polymers are formed from compounds sourced/ produced from crude oil, saves precious resources polymers need collecting/ sorting- expensive process in terms of energy and manpower polymers can only be recycled into the same type- so careful separation needs to be done thermoplastic polymers can be melted down and reshaped