polymers

Question 1

condensation polymers are formed by reactions between and what they form

Answer 1

dicarboxylic acids and diols –> polyester + H2O
dicarboxylic acids and diamines -> polyamides + H2O
amino acids –> polypeptides + H2O

Question 2

the repeating units in polyesters and the linkage between these units

Answer 2

HO-CO-R-CO-O-R’-O-H
ester link CO-O

Question 3

the repeating units in polyamides and there linkage between these repeating units

Answer 3

HO-CO-R-CO-NH-R’-NH-H
amide link CO-NH

Question 4

one example of a polyester repeating units and what is made from and uses

Answer 4

terylene
made from ethane-1,2-diol and benzene-1,4-dicarboxylic acid
used in plastic bottles, clothing, sheets and sails

Question 5

2 examples of polyamides repeating units and what is made from and uses

Answer 5

nylon 6,6
made from 1-6-diaminohexane and hexane-1,6-dicarboxlic acid
used to make clothing, carpet, rope and airbags

kevlar
made from benzene-1,4-diamine and benzene-1,4-dicarboxlic acid
used in bulletproof vests, boat construction, car tyres and lightweight sports equipment

Question 6

explain the nature of the intermolecular forces between molecules of condensation polymers

Answer 6

condensation polymers are made up of chains containing polar bonds (C-N and C-O) so as well as IDD forces there are PDD and hydrogen bonds between polymer chains so condensation polymers are generally stronger and more rigid than addition polymers

Question 7

are polyalkenes biodegradable

Answer 7

polyalkenes are addition polymers that have non-polar C-C bonds that can cannot be hydrolysed which makes them unreactive and chemically inert. they are non-biodegradble

Question 8

are polyesters and polyamides biodegadable

Answer 8

condenstaion polymers so do have polar bonds in their chains which makes them open to attack by nucleophiles so can be broken by hyrdolysis so biodegrable

Question 9

advantages and disadvantages of different methods of disposal of polymers

Answer 9

buried (landfill)- cheap, easy method BUTrequires areas of land

burned - heat used to produce electricity, BUT needs to be controlled to reduce release of toxic gases, contributes to greenhouse effect

recycled- reduces amount of water going into landfill, saves raw materials, cost of recycling lower than making from scratch, less CO2 emissions BUT technically difficult to recycle plastics, collecting sorting ad processing more expensive than landfill, often cant remake the plastic you started with, easily contaminated