Chapter 27.3 Flashcards
What is addition polymerisation?
when alkenes form polymers by breaking the double bond [?]
What is condensation polymerisation?
the joining of monomers with loss of a small molecule - usually H2O - or hydrogen chloride.
What type of polymers are polyesters and polyamides?
condensation polymers
What is needed for condensation polymerisation to occur?
Two different functional groups
Structure of polyester
monomers joined by ester linkages
Process of polyester production
From one monomer containing both COOH and OH group or two monomers, one containing COOH and the other having two alcohol (hydroxyl, -OH) groups (a diol).
How do we show the repeat unit on a displayed formula of a polymer?
with square brackets
-COOH and -OH form what?
an ester linkage: [rest of it]-CO-O-[rest of it]
What is a carboxyl group and what does this make the molecule?
-COOH, it is a carboxylic acid
What is a hydroxyl group and what does this make the molecule? What about when there are two hydroxyl groups?
-OH, alcohol, diol
What is terylene?
aka PET, a condensation polymer, polysester specifically (as it has ester linkages) that is used for many things such as plastic bottles.
What is a common use of polyesters?
Electrical insulation
How else can a polyester be made (not using a carboxylic acid)?
By using a diacyl chloride not dicarboxylic acid [?]. Hydrogen chloride is lost instead of H2O.
What are polyamides?
Condensation polymers formed when monomers are joined by amide linkages.
Process of polyamide production
Made from one monomer containing both COOH (or acyl chloride) and an amine group. Or from two monomers, one containing two COOH - dicarboxylic acid - (or acyl chloride) groups and the other containing two amine group - a diamine.
What are amino acids?
Molecules containing both an amine group and a carboxylic acid group.
How are polypeptides/ proteins formed?
amino acids undergoing condensation polymerisation, the forming amide linkages. Water is lost.
What is the structure of an amide linkage?
-CO-NH- that is carbon and nitrogen atoms bonded together with an oxygen atom double bonded to the carbon and a hydrogen atom bonded to a hydrogen atom.
What are polypeptides an example of?
Polyamides formed from one monomer with two functional groups by condensation polymerisation.
What is nylon an example of?
A polyamide formed from two monomers each with two functional groups - a diamine and dicarboxylic acid.
How does an amide linkage form?
-COOH and NH2- lose the one of the nitrogen’s H atoms and the OH of the COOH to get the amide linkage.
How can condensation polymers be hydrolysed?
By using hot aqueous alkali such as sodium hydroxide (NaOH) or by hot aqueous acid such as HCl. Aqueous because we are splitting the polymer with water.
How can polyesters be hydrolysed?
The Na+ of the base or H+ of the acid join onto the left over COO- [?].
How an polyamides be hydrolysed?
With bases, the Na+ joins the COO- and the nitrogen atoms get another H to go back to NH2-. With acids, the H+ joins the COO- so it goes back to normal COOH. The nitrogen atom gains two H+ ions so it becomes NH3+ and still attahed to a carbon atom.
