Download Synthetic Polymers

STUDY PACK : 11.5
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Macromolecules
1.
i.
What are Polymers?
Polymer is an organic macromolecule formed by many small molecules joining
together.
ii.
What are monomers?
The small molecules referred above are called monomers.
iii.
What is Polymerization?
The process of joining monomers to form polymers.
2. Polymers are made by two different processes. Name them & describe each in detail giving
examples.
Addition Polymer (homo polymer) :
I.
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Same kind of monomers joins together to form the polymer.
Addition reaction takes place across a C=C bond.
No by-product formed during polymerization.
Condensation Polymer (co-polymer) :
II.
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Different kinds of monomers join together to form the polymer.
Elimination reaction takes place between two monomers.
Simple molecules such as H2O, HCl is given off as bi product.
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3.
Describe the type of reactions takes place in addition & condensation
polymerization
4.
Describe the formation of poly(ethene) [polythene] & draw the structure of the
monomer unit & the polymer stating all the conditions
Monomer ethene is used in the manufacture of the addition polymer polyethene.
polythene/polythene is produced as a white waxy solid when ethene monomer is
heated to high temperature and pressure. Ethene monomers join together across
the C=C by addition reaction.
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5.
Draw the structures of the below monomers, which are derivations of ethane.
Styrene
6.
Vinyl Chloride
Propene
Apply the principles of addition polymerization to describe the formation of
Polychloroethene (Polyvinyl chloride-PVC) from chloro ethene
The reaction is exactly same as for ethene. The extra chlorine atom repeats
throughout the polymer structure.
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7.
8.
Similarly apply the principles of addition polymerization to the below monomers &
draw the structures of their respective polymers & name them.
i.
Propene
ii.
Polychloroethene (Polyvinyl chloride-PVC)
Describe the formation of condensation polymers using the formation of esters &
amides, and identify the peptide linkage.
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9.
i.
Draw & name the monomers that are used in the manufacture of the condensation
polymer Nylon
ii.
Describe the formation of nylon & draw its structure in a block diagram format.
Nylon is the first synthetic fibre produced. It is a condensation polymer made by
the reaction between diamine & a dicarboxylic acid. Both ends of the monomer are
functional groups.
An amine group on the first monomer reacts with a carboxylic group on the second
monomer to make a amide/ peptide link between the two molecules. Each time a link
is made a water molecule is lost.
As many amide/ peptide linkages are formed during polymerization Nylon is also
called as poly amide/ ploy peptide.
The equation for the reaction is:
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iii.
10.
Describe the laboratory synthesis of nylon using a diagram
Apply the principles of condensation polymerization to describe the formation of the
condensation polymer Terylene
Polyesters (many ester linkages) is a condensation polymer which is formed by the
reaction between benzene 1,4-dicarboxylic acid (or di acid chloride) with ethan1,2-diol. The common most polymer is Terylene which is also called as Poly Ester.
Terylene is used in the manufacture of synthetic fibers. Eg: Polyester in clothing,
terylene is also a good thermal insulator.
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11. Write the uses of the below synthetic polymers.
Polythene
:
Nylon :
Terylene
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P.V.C- polyvinyl chloride
Polystyrene
12.
i.
:
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Explain what is meant by the term “non-biodegradable”
This means natural micro-organisms cannot decompose or breakdown the compound.
ii.
Describe the environmental problems caused by the disposal of non-biodegradable
plastics
Solid non-biodegradable waste consumes the most space resulting serious
problems represented by overflowing of landfill sites thus results in shortage
of new landfill space.
Toxic gases are released when plastics are burnet which causes variety of
health problems.
Recycling of plastics will reduce the demand on raw materials (monomers). This
also will be a solution for many environmental problems, which are caused by the
disposal of non-biodegradable polymers.
15. Give some examples for natural / Biological polymers
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Natural Macromolecules
16.
Describe the polymerisation of amino acids to form proteins, hence compare the
structural similarities & differences of nylon & proteins.
Proteins are built from amino acid monomers; each amino acid contains two
functional groups, an amine group & a carboxylic group. When two amino acids react
together an amide linkage (peptide linkage) is formed to form a dipeptide (2 amino
acids together) there are 20 different amino acids. Different amino acids react to
form different proteins.
When the above process is repeated several times with different amino acids, a
polymer is formed. Proteins are categorized according to the number of amino
acids linked.
Proteins posses the same amide linkage as nylon but with different monomer
units.
17.
Describe the hydrolysis of proteins to amino acids.
Proteins can be hydrolysed (brocken down) to amino acids by heating with dilute
acids, This is the reverse of the condensation process. The mixture of amino acids
can be separated by chromatography.
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18.
Describe fats as esters possessing the same linkage as Terylene but with different
monomer units.
Animal fat & vegetable oils are esters of glycerol & fatty acids. Gycerol is an
alcohol with 3 –OH groups & fatty acids are long chain carboxylic acids. A glycerol
molecule reacts with 3 fatty acids to form the ester fat.
When a fat or oil is heated with NaOH alkali hydrolysis takes place resulting
glycerol & sodium salt of fatty acids which is soap.
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19.
Describe the condensation polymerisation of carbohydrates.
A carbohydrate is a compound containing ‘C’, ‘H’ &’O’ only. The ratio of hydrogen to
oxygen is always 2:1.
Eg:
Sucrose (C12H22O11)
Glucose (C6H12O6)
Simple sugar molecules (Glucose, Fructose, Galactose) are known as
monosaccharides (C3-C7) Condensation polymerization of these simple sugar
monomers (monosaccharides) produces long chain polysaccharides known as
carbohydrates. (eg: starch, glycogen, cellulose)
20.
Describe the hydrolysis of carbohydrates to simple sugars
When carbohydrates are digested they are brocken down back to glucose to
release energy (ATP). The glucose is then oxidized by respiration.
Polysaccharides can be brocken down in the laboratory by warming with HCl acid.
This process is known as acid hydrolysis.
Imran Razeek
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