Synthetic Polymers Flashcards
What are polymers?
polymers are large molecules of high relative molecular mass and are made by linking together large numbers of smaller molecules called monomers
What is the process of linking together large numbers of smaller molecules called monomers to produce polymers called?
addition polymerisation
What kind of bonds joins each monomer (repeat unit) and connect them to the adjacent units?
covalent bonds
What does the polymerisation process require usually?
polymerisation reactions usually require high pressures and the use of a catalyst
What are some examples of everyday materials that are polymers?
resins, plastics, polystyrene cups, nylon
What are materials such as: resins, plastics, polystyrene cups, nylon usually called?
synthetic polymers
What are the polymers that nature can produce called?
natural or biological polymers
What are the 3 stages of polymerisation?
monomer —> polymerisation —> polymer
What do monomers have to contain to be able to become addition polymers?
C=C bonds
What happens to the structure of a monomers when becoming an addition polymer?
one of the bonds in each C=C bond breaks and forms a bond with the adjacent monomer with the polymer being formed containing single bonds only
What are many addition polymers made of?
many polymers can be made by the addition of alkene monomers
What are other addition polymers made of if it is not the addition of alkene monomers?
others are made from alkene monomers with different atoms attached to the monomer such as chlorine or a hydroxyl group
How are polymers named?
the name of the polymer is deduced by putting the name of the monomer in brackets and adding poly- as the prefix
What does the name of all polymers begin with?
poly-
What is poly (ethene) formed by?
polyethene is formed by the addition polymerisation of ethene monomers
If propene is the alkene monomer used, what is the name of the polymer?
poly (propene)
How would you draw a repeating unit for addition polymers?
repeat units are used when displaying the formula
to draw a repeat unit, change the double bond in the monomer to a single bond in the repeat unit
add a bond to each end of the repeat unit
the bonds on either side of the polymer must extend outside the brackets (these are called extension or continuation bonds)
a small subscript n is written on the bottom right hand side to indicate a large number of repeat units
add on the rest of the groups in the same order that they surrounded the double bond in the monomer
How would you deduce the monomer from the polymer?
identify the repeating unit in the polymer
change the single bond in the repeat unit to a double bond in the monomer
remove the bond from each end of the repeat unit and the subscript n (which can be placed in front of the monomer)
How are addition polymers formed?
addition polymers are formed by the joining up of many small molecules with strong C-C bonds
What are some key features of addition polymers and why are they features?
addition polymers are unreactive and chemically inert so don’t easily biodegrade because of the strong C-C bonds
How do addition polymers affect landfills?
waste polymers are disposed of in landfill sites but this takes up valuable land, as addition polymers are non-biodegradable so micro-organisms such as decomposers cannot break them down
this causes sites to quickly fill up
How does the burning of addition polymers contribute to the release of toxic gases as well as affecting humans?
polymers release a lot of heat energy when they burn and produces carbon dioxide which is a greenhouse gas that contributes to climate change
polymers that contain chlorine such as PVC release toxic hydrogen chloride gas when burned
if incinerated (burned) by incomplete combustion, carbon monoxide will be produced which is a toxic gas that reduces the capacity of the blood to carry oxygen
What is the meaning of biodegradable?
the breakdown of a substance by microorganisms
When are condensation polymers formed and how?
condensation polymers are formed when two different larger monomers are linked together with the removal of a smaller molecule, usually water or hydrogen chloride
What is the key difference between condensation polymers and addition polymers?
addition polymerisation forms the polymer molecule only
condensation polymerisation forms the polymer molecule and one water molecule per linkage
What are polyesters formed by?
a dicarboxylic acid (a carboxylic acid with two -COOH- groups)
and a diol (an alcohol with two -OH- groups)
Which of the larger monomers gives the -OH molecule to create the by-product of water?
the dicarboxylic acid
For every ester linkage formed in condensation polymerisation, what is released?
for every ester linkage formed in condensation polymerisation, one molecule of water is formed from the combination of a -H and an -OH group
What happens during condensation polymerisation?
each -COOH group reacts with another -OH group on another monomer
an ester linkage is formed with the subsequent loss of one water molecule per link
Which of the larger monomers gives the -H molecule to create the by-product of water?
the diol
How can the structure of polyester be drawn?
they can be represented by drawing out the polymer using boxes to represent the carbon chains
this can be done for all polyesters
When trying to deduce the two larger monomers from the polyester, how should you think of it?
it helps to think of this as the reversal of the formation of a polyester
when a polyester is formed, small molecules of water are removed
the OH comes from the acid / -COOH groups of the dicarboxylic acid
the H comes from the alcohol / -OH groups of the diol
What is the process of adding water to the polyester to allows it to break back down into its monomers?
hydrolysis
What is the key point you should remember about polyesters?
when the polyester was made, the dicarboxylic acid lost OH groups and the diol lost H atoms
What are biopolyesters?
biopolyesters are a specific type of polymers that are synthesised from sugars and plant oils using microorganisms
What are biopolyesters able to do that regular polyesters cannot?
they are able to biodegrade naturally in the environment after their intended purpose
Why are biopolyesters biodegradable?
the polymers are synthetically made, consisting of ester, amide and ether functional groups which gives them the characteristic of being biodegradable
