polymers Flashcards
What is a condensation polymer?
A polymer formed when monomers join together to form a small molecule of water/hcl
Name two types of condensation polymer
Polyesters
Polyamides
What monomers are needed to form polyesters?
Dicarboxylic acids and diols
or a single compound with a carboxyl and alcohol group
name a polyester
PET - poly(ethylene terephthalate)
Terylene
what are the monomers needed to make PET
ethane-1,2-diol
benzene-1,4-dicarboxylic acid
name uses for PET
plastic bottles, clothing
name examples of polyamides
nylon 6,6
kevlar
what are the monomers needed in nylon
hexane-1,6-dioic acid
hexane-1,6-diamine
what is a polyester?
a polymer where the monomers are held together by ester linkages
what is a polyamide?
a polymer where the monomers are held together by amide linkages
what is formed in the alkaline hydrolysis of polyesters such as terylene?
ethane-1,2-diol and the salt of the carboxylic acid
name polyamides
kevlar
nylon-6,6
what are the monomers which form nylon-6,6?
hexane-1,6-diamine
hexane-1,6-dioic acid
what are the polymers which form kevlar?
benzene-1,4-dicarboxylic acid
benzene-1,4-diamine
how is hexane-1,6-dioic acid formed industrially?
oxidation of cyclohexane
how is hexane-1,6-diamine formed industrially?
treat hexane-1,6-dioic acid with ammonia to form ammonia salt
heat this to 350 degrees in the presence of hydrogen to form hexane-1,6-diamine
what bonding is found in polyesters?
permanent dipole-dipoles
van der Waals forces
what bonding is found in polyamides?
hydrogen bonding
permanent dipole-dipole interactions
van der Waals
what bonding is found in addition polymers?
van der Waals
by what process can you break down terylene
alkaline hydrolysis
how can alkalis break down terylene?
alkali breaks the ester linkages
how do you make nylon in a lab?
react hexanedioyl dichloride with the hexane-1,6-diamine
by what process can you break down polyamides?
acid hydrolysis
which is more resistant to hydrolysis, kevlar or nylon?
kevlar
what is a biodegradable polymer?
a polymer which can be broken down in the environment by microorganisms
why are polyalkenes inert?
because they’re saturated and have no double bonds or polar groups so they’re chemically inert.
what are the advantages of polyalkenes being inert?
they’re durable
what are the disadvantages of polyalkenes being inert?
cannot be disposed of easily - build up in the environment
why do condensation polymers hydrolyse faster in compost heaps?
warmer
more water
microorganisms (bacteria)
more light
name ways in which polymers can be disposed
landfill
incineration
recycling
what are the advantages of using landfill sites?
the most cost-effective way of getting rid of polymers
what are the disadvantages of using landfill sites?
wastes land
pollutes land with non-biodegradable polymers
releases methane which is a greenhouse gas
eyesore
what are the advantages of incineration?
prevents use of ugly landfills
saves money on transportation of waste
produces heat energy which can be used to generate electricity
what are the disadvantages of incineration?
produces greenhouse gases like CO2
releases toxic gases like SO2 (acid rain)
more expensive
still produces waste for landfills
what strategies are there to control polymer waste?
reduction in the use of polymers
reduction in the use of carrier bags
dedicated polymer recycling
use more biodegradable polymers
what are proteins?
sequences of amino acids joined together by peptide bonds (amide linkages)
what is the primary structure of a protein?
the order of the amino acids
what is the secondary structure of a protein?
the folding or coiling of the chain of amino acids
what is the tertiary structure of a protein?
final folding of a protein molecule
give some of the characteristics of amino acids
melting point of 200 degrees
soluble in water
form optical isomers
why do amino acids have such a high melting point?
in the solid state they form zwiterions so there are ionic bonds between the amino acids
what are zwitterions?
molecules with no overall charge but have positive and negative parts of the molecule
why are amino acids soluble in water?
because there are interactions between the polar water molecules and the zwitterions
why are amino acids insoluble in non-polar substances like alkanes?
lack of attraction
why can amino acids form optical isomers?
bc they have a chiral carbon
in what reaction are proteins formed?
condensation reactions
what are the two types of secondary structures in proteins?
alpha helix
beta pleated sheets
what is an alpha helix?
a right handed helix
when do proteins form alpha helices?
when they have small R groups
what bonds are found in the secondary structure?
hydrogen bonds
how is a beta pleated sheet formed?
when amino acids chains fold so they’re facing each other and hydrogen bonds form between NH and CO groups
what is the tertiary structure of the protein?
the final folding of the protein in 3D space
how do the interactions form in the tertiary structure?
interactions between the R groups
what interactions are found in the tertiary structure?
hydrogen bonding
van der Waals forces
ionic bonds
disulfide bridges
what is the main structure in fibrous proteins?
secondary
give characteristics of fibrous proteins
strong
resistant
insoluble
what are globular proteins?
spherical proteins mainly with a tertiary structure
what are enzymes?
biological catalysts
what type of protein are enzymes?
globular proteins
explain the mode of action of catalysts
substrates are the reactants
specific to the active site
fits into active site and strains the bonds
turns it into a product
product is non-comp. so it doesnt fit the enzyme and is dissociated
what is the active site?
foldings of the protein in the tertiary structure which are specific to substrates
what is meant by the active site being stereospecific?
is a substrate has two stereoisomers, then only one will fit into the active site
how do enzyme inhibitors work
they’re of a similar shape to the active site so they bind to it instead of the substrate
how are proteins broken down?
hydrolysis. boil the protein with hydrochloric acid
how can amino acids be analysed?
TLC
why can polyesters be hydrolysed?
the polar C=O group can be attacked by nucleophiles
