Condensation polymerisation

how are condensation polymers formed?

condensation reaction, so a water molecule is removed

3 types of condensation polymers?

polyamides, polyesters, polypeptides

how are polyamides formed?

condensation reaction between dicarboxylic acid and a diamine,

water is removed leaving an amide linkage

what makes polyamides strong?

polyamides commonly formed from long chain molecules which provides them with strngth

by convention, the repeat unit isnt shorter than how many carbons?

2

(lots) diol + (lots) dicarboxylic acid -> ? + ?

polyester + water

ester functional group?

COO

what are ester links?

the link produced when an ester is formed

from a carboxylic acid and an alcohol

what is a polyester?

condensation polymer in which monomers are joined with an ester linkage, contains more than 1 ester functional group

when are two monomer polyesters formed?

condensation reaction between 1 monomer of dicarboxylic acid and 1 diol

what does the repeat unit in a two monomer polyester contain?

2 oxygen atoms, 2 carbonyl groups, everything between the oxygens and carbonyl group

single monomer polyester?

polyester formed from a singular monomer (monomers containing an alcohol and carboxylic acid group react)

what does the repeat unit in a single monomer polyester contain?

1 oxygen atom, 1 carbonyl group, everything between oxygen and carbonyl group

carboxylic acid + amines -> ? + ?

amide + water

what type of reaction is carboxylic acid + amines?

condensation

lots diamine + lots dicarboxylic acid -> ? + ?

polyamide + water

(two monomer polyamide)

what is a polyamide?

condensation polymer in which the monomers are joined through amide linkages

what does a two monomer polyamide repeat unit contain?

two N-H groups, 2 carbonyl, everything between N-H and carbonyl groups

what single monomer forms a polyamide via condensation?

monomers that contain an amine and carboxylic acid group

what does a single monomer polyamide repeat unit contain?

1 N-H group, 1 carbonyl, everything between N-H and carbonyl

what are condensation polymerisation reactions?

any reactions where a monomer reacts to form a polymer and a small molecule (H20/HCl)

diol + diacyl chloride -> ? + ?

polyester + HCl

what does condensation of 1 monomer contaning an OH and COCl group produce?

polyester + HCl

diamine + diacyl chloride -> ? + ?

polyamide + HCl

what does condensation of 1 monomer contaning an NH2 and COCl group produce?

polyamide + HCl

2 types of condensation polymers?

polyesters and polyamides

3 condensation polymer examples?

terylene, nylon 6,6 and kevlar

properties of these condensation polymers?

strong!, high melting and boiling points

terylene: ship sails

nylon 6,6: parachutes

kevlar: bulletproof vests

terylene is an example of which condensation polymer?

polyester

nylon 6,6 is an example of which condensation polymer?

polyamide

kevlar is an example of which condensation polymer?

polyamide

how to distinguish between kevlar and nylon 6,6's repeat units?

kevlar has benzene rings

common name of a polyester?

terylene

why do polyesters have high melting points?

• strong van der waals forces due to a lot of e-

• polar C=O double bond = permanent dipole-dipole forces, increasing intermolecular forces

why do polyeamides have high melting points?

• strong van der waals forces due to a lot of e-

• polar C=O double bond = permanent dipole-dipole forces, increasing intermolecular forces

• N-H bond = hydrogen bonding

why do addition polymers have lower m.p. than condensation polymers?

only have van der waals forces

why is kelvar stronger/has a higher m.p. than nylon 6,6 despite them both being polyamides?

• nylon 6,6: arranged in long, flexible chains

• kelvar: planar benzene rings = can stack closely = increases number of hydrogen bonds between chains = increases intermolecular forces strength

3 ways to dispose of plastics?

• landfill

• incineration

• recycling

what is landfill?

solid waste is buried, vegetation can grow on top

what is incineration?

burning of solid waste (plastic) = energy production as it turns turbines

what is recycling?

Converting waste into reusable material:

• sorted into polymers

• some melted and remoulded

• some separated into its monomers

advantages of recycling?

• reduces production of harmful chemicals, like dioxins

disadvantages of recycling?

• cheaper to put in landfill or incinerate

• takes longer

• easy for plastic to get contaminated during recycling -> landfill

• some plastics cant be recycled

• you cant always make the plastic you started off with, so need to make it new if you want that

Define biodegradable

can be hydrolysed by living things into naturally occuring molecules within 6 months, such as CO2 and H2O

is PVC biodegradable?

no

is PLA biodegradable?

yes

what type of polymer is PVC?

addition polymer

what type of polymer is PLA?

condensation polymer

are condensation polymers biodegradable?

yes

are addition polymers biodegradable?

no x

why are condensation polymers biodegradable and addition polymers arent?

to hydrolyse, you'd need to break the chain:

addition polymers - C-C bond - strong + non polar

condensation: break amide or ester link (EASIER)

why are C-C bonds difficult to break?

strong and non polar -> unreactive and difficult to break

polyesters can be hydrolysed with water to form what?

carboxylic acid + alcohol

why can water react with polyesters and polyamides for hydrolysis?

ester/amide links contain C=O pola bonds, carbon has a slight positive charge, so nucleophiles (water) can attack it

why arent addition polymers biodegradable?

contain C-C non polar bonds, so cant be attacked by nucleophiles (water)