polymers Flashcards
addition polymer
An addition polymer forms when unsaturated monomers react to form a polymer
Monomers contain C=C bonds
why r poly(alkenes) chemically inert
Poly(alkenes) are chemically inert due to the strong C-C and C-H bonds and non-polar nature of the bonds and therefore are non-biodegradable.
condensation polymer
there are two different monomers that add together and a small molecule is usually given off as a side-product e.g. H2O or HCl.
Forming polyester
dicarboxylic acid + diol poly(ester) + water
diacyl dichloride + diol poly(ester) + HCl
Forming polyamide
dicarboxylic acid + diamine poly(amide) + water
diacyl dichloride + diamine poly(amide) + HCl
disadvantage of using CA to make ester/amide
would need an acid catalyst and would only give an equilibrium mixture.
adv + disadvantage of using acyl chloride
goes to completion and does not need a catalyst but does produce hazardous HCl fumes.
what is terylene
common polyester
how is terylene made
from Benzene-1,4-dicarboxylic acid + Ethane-1,2-diol
OR
Pentanedioyl dichloride + Benzene-1,4-diol
what is nylon 6,6
common polyamide
what is nylon 6,6 made from
The 6,6 stands for 6 carbons in each of the monomers.
hexanedioic acid
Hexane-1,6-diamine
what is kevlar
common polyamide
draw structure of terulene
draw structure of nylon 6,6
draw structure of kevlar
what is kevlar made from
what to say if asked what type of polymer
polyamide or polyester
type of polymerisation
addition/condensation
are polyesters + polyamides biodragable why?
polyesters and polyamides can be broken down by hydrolysis and are, therefore, biodegradable
Hydrolysis of Polyesters and polyamides
by acid and alkali
The hydrolysis will result in the original monomers forming- although the carboxylic acid or amine group will be in salt form depending on whether the conditions are alkaline or acidic
Intermolecular bonding between condensation polymers chains
Polyesters have permanent dipole forces between the Cδ+=Oδ- groups in the different chains in addition to
the van der waals forces between the chains.
Polyamides (and proteins) have hydrogen bonding between the oxygen in Cδ+=Oδ- groups and the H in the Nδ- —Hδ+ groups in the different chains in addition to the van der waals forces.
Polyamides will therefore have higher melting points than polyesters.
Disposal of Polymers
landfill, incineration, recycling
incineration + -
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 is greatly reduced.
recycling + -
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
