Condensation polymers Flashcards
what is condensation polymerisation?
examples of natural and synthetic polymers?
In condensation polymerization, monomers are joint together. Each monomer has at least two functional groups and every time a link is made to extend the polymer a small molecule, such as water, is lost.
Natural condesation polymers: proteins and silk
Synthetic condensation polymers: nylon and kevlar
What are polyester and polyamide fibres used for?
to make clothes
dicarboxylic acid
contain 2 carbonyls
-dioic
even the carbons in the carboxyl groups are included in the name
dicarboxylic acid + diol
polyester / ester is made
ester still has carbonyl group and hydroxyl group so can react with more molecules to forma long polyester chain
water is also made
terylene
terylene is made from benzene-1,4-dicarboxylic acid and ethane-1,2-diol
the polymer is called polyethylene terepthalate or PET. it is used to make plastic drinks bottles.
the polymer is drawn into fibres called terylene which is used to make clothes
terylene makes fabric less likely to crease and last longers
diamines
diamines have 2 amine groups -NH2
making synthetic polyamides
amide links are made between molecules with a carboxyl group and another with an amine group
polyamides are made by reacting dicarboxlyic acids with diamines
all these molecules have a functional group at each end of the molecule so can form very long polymer chains
nylon
nylon 6,6 is a synthetic polyamide used to makes rope and clothes
it is made from 1,6-diaminohexane and hexane-1,6-dicarboxylic acid
the “6,6” part of the name comes from the number of carbon atoms in the diamine and the second comes from the number of carbon atoms in the dicarboxylic acid
kevlar
kevlar is another useful synthetic polyamide
it is used to make bullet proof vests
it is light, very stronfg and has a high melting point
it is made by condensation polymerization between benzene-1,4-diamine and benzene-1,4-dicarboxylic acid
biodigradable
biodigradable materials can be broken down by microorganisms
what plastics are non-biodigradable?
polakenes such as poly(ethene) and poly(propene) are made by addition polymerization. addition polymers are saturated which makes them chemicall inert and non diodigradable.
what acids are diodigradable?
polyesters and polyamides are diodegradable and can be hydrolysed by acids or alkalis.
it is much easier to dipose of these plastics.
poly(lactic acid)
poly(lactic acid) is a condensation polymer made from 2-hydroxypropanoic acid (lactic acid) which is made from corn starch.
poly(lactic acid) is used to make waste sacks and disposable eating utensils, chemists have developed polymers such as poly(lactic acid) which degrade naturally in the environment because this reduces the amount of waste in landfill sites.
hydrolysis of polyesters
polyesters can be hydrolysed by hot aqueous acids or alkalis. each of the ester linkages in the polyester is hydrolysed
hydrolysis by hot aqueous hydrochloric acid produces the monomers used to make the polyester
hydrolysis by hot sodium hydroxide the sodium salt of the dicarboxylic acid and the diol
hydrolysis of polyamides
polyamides can also be hydrolysed by hot aqueous acids or alkalis. the amide linkages in the polyamide are hydrolysed
hydrolysis by hcl produces the ammonium salt of the diamine and the dicarboxylic acid
hydrolysis by hot aqueous sodium hydroxide produces the diamine and the sodium salt of the dicarboxylic acid
