3.3.12
Flashcards
Interactive study deck for condensation polymers and waste disposal.
Polymers: read all 18 questions and answers
- What is a condensation polymer?A polymer formed by the reaction of monomers containing two functional groups, releasing a small molecule (such as water or hydrogen chloride) at each linkage.
- State the two monomers used to make Nylon-6,6.Hexanedioic acid and 1,6-diaminohexane.
- State the two monomers used to make Kevlar.Benzene-1,4-dicarboxylic acid (or benzene-1,4-dicarbonyl chloride) and benzene-1,4-diamine.
- State the two monomers used to make Terylene (PET).Benzene-1,4-dicarboxylic acid and ethane-1,2-diol.
- What type of linkage is present in Terylene?Ester linkage (-COO-).
- What type of linkage is present in Nylon-6,6 and Kevlar?Amide linkage (-CONH-).
- Why do polyamides have higher melting points than polyesters?Polyamides form strong hydrogen bonds between the N-H group in one chain and the C=O group in another, whereas polyesters form weaker permanent dipole-dipole forces.
- Write the repeat unit of the polymer formed from 2-hydroxypropanoic acid (lactic acid).-[O-CH(CH3)-CO]-
- Why are condensation polymers biodegradable?They contain polar ester or amide bonds in their backbone, which can be attacked by nucleophiles (like water) and hydrolysed.
- Why are addition polymers non-biodegradable?They have a non-polar carbon-carbon backbone which is very strong and cannot be easily hydrolysed by water, acids, or alkalis.
- Write the products of the acid hydrolysis of Nylon-6,6.Hexanedioic acid and the protonated salt of the diamine (1,6-hexanediammonium ions).
- Write the products of the alkaline hydrolysis of Terylene.Sodium benzene-1,4-dicarboxylate (the carboxylate salt) and ethane-1,2-diol.
- What small molecule is eliminated when a diol reacts with a diacyl chloride to form a polyester?Hydrogen chloride (HCl).
- Explain why Kevlar is extremely strong.The planar aromatic benzene rings allow the chains to pack closely together, maximizing hydrogen bonding between adjacent amide linkages.
- What is a major disadvantage of polymer disposal by incineration?It releases carbon dioxide (a greenhouse gas) and can produce toxic gases like hydrogen chloride (HCl) if chlorinated polymers like PVC are burned.
- State an advantage of recycling polymers over landfilling them.It conserves finite crude oil resources and reduces the amount of non-biodegradable waste taking up space in landfill sites.
- Can polyesters be hydrolysed by water alone?Yes, but the reaction is extremely slow; it is catalysed by aqueous acids or bases.
- Draw the monomer of poly(propene).Propene (CH2=CHCH3).