Polymers Model Answers Flashcards
Why is polyester degradable?
Polar C-O bonds can be attacked by nucleophiles/H+/OH-
State how the strongest IMF occur between the chains of the polyamide?
Polyamides have hydrogen bonds between their chains
There is large difference in electronegativity between N and H
The H delta plus of N-H forms attraction to the lone pair on the O delta minus of the C=O bond
Why is nylon degraded by hydrochloric acid whereas polyethene is not?
Polyamides contain polar C-N bonds, the H+ delta plus ions can attack the N delta minus atoms and break the amide bond
Polyethene is an addition polymer which has strong non-polar C-C bonds which cannot be attacked and broken by H+
Outline difference between the formation of addition polymer and condensation polymer
Addition= joining together of monomers with one double bond, one product only
Condensation: also involves elimination of small molecule
Name of linkage in polyamide
peptide bond or amide bond
What is the difference between the biodegradability of polyamides compared to polymerised alkenes? Explain
Polyamides biodegradeable but polyalkenes are not
Polyamides have polar bonds/peptide link
Polyamide can be hydrolysed/attacked by acids/enzymes/bases
Polyalkenes have non-polar bonds
Why are polyamides degraded by sodium hydroxide but polyalkenes are not?
Polyamides can be hydrolysed
OH- attacks peptide link or C delta plus
Polyalkene non-polar
Describe experiment in which to compare biodegradeability of polyalkene and polyamide
Reflux with NaOH
Polyalkene inert no reaction
Polyamide is hydrolysed to form carboxylate salt and amine
Advantage and disadvantage of combustion of plastics as disposal method
+ heat energy produced
- toxic gases produced
how to purify a precipitate
filter off precipitate
wash to remove soluble compounds
dry to remove water
