However, there are problems with incineration. Carbon dioxide is produced, which adds to global warming. Toxic gases are also produced, unless the polymers are incinerated at high temperatures. Recycling polymers is a good idea, but not always practical. Many polymers are mixed with other materials and paints or dyes and separation is difficult and expensive. The bonds between repeating units are non polar so not susceptible to attack by nucleophiles. Why are polyalkenes not biodegradable.
They're chemically inert. Why are condensation polymers biodegradable. Bonds between repeating units are polar and can be attacker by nucleophiles. Advantages of landfill. Cheap Easy method. Disadvantages of landfill.
Requires lots of land Decomposing waste releases methane As waste decomposes it releases toxins which can be washed away and contaminate water supplies. Advantages of burning waste plastic. Heat used to generate electricity. Disadvantages of burning waste plastics. Previous Polymers A-level only. Next undefined. Polyalkenes are chemically inert and non-biodegradable. Polyesters and polyamides can be broken down by hydrolysis and are biodegradable. Students should be able to: explain why polyesters and polyamides can be hydrolysed but polyalkenes cannot.
LDPE contains lots of branches off the polymer chains, and reactions involving UV light produce free radicals at these junctions. More interactions with UV can split the chains around the carbonyl groups. This is all very complicated, and I am not the least bit confident about it!
Nobody is going to expect you to learn it. Just be aware that some polymers can be degraded by light, and perhaps remember that LDPE is one example of this. I'm not certain what CIE want here. The statement talks about polyesters and polyamides being biodegradable, which implies that they can be broken down by organisms involving enzyme-controlled hydrolysis of the ester or amide links.
But the details of that are way beyond an A level chemistry course.
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