Polymerisation

Predict the number of peaks that will be seen in the carbon-13 NMR spectra of F and G.

Draw the repeat unit of polyhydroxyamide. The amide bond should be shown displayed.

When poly(ethene) is formed from ethene, many bonds are broken and formed.

Place one tick (✓) in each row of the table to indicate the types of bonds broken and formed in this process.

Addition polymers can be classified into two types.

• homopolymer - a polymer made up of the same monomer unit
• copolymer - a polymer made up of two or more different monomer units

The reaction of propene, $\text{CH}_3\text{CH}=\text{CH}_2$, with phenylethene, $\text{C}_6\text{H}_5\text{CH}=\text{CH}_2$, gives a copolymer.

Draw a length of the chain of this copolymer that contains one molecule of each monomer.

Polyalkenes biodegrade very slowly.

Explain why by referring to the structures of the polymers.

Some polymers will degrade in the environment.

Describe two processes by which this occurs.

1 ..........................................................................................................................................

2 ..........................................................................................................................................

Complete the table by placing a tick ($\checkmark$) in the correct column to indicate the type of reaction that would polymerise each of the monomers.

Poly(ethene) bags pollute the environment for a long time because they are non-biodegradable.

Suggest why.

Draw the structure of the monomer for PLA.

Suggest why PLA breaks down more easily in the environment than poly(ethene).

The table shows the melting points of three polymers.

Explain the differences in melting point of these three polymers in terms of the intermolecular forces between the chains.

Name an example of a synthetic addition polymer and a synthetic condensation polymer.

addition polymer

condensation polymer

What type of reaction occurs when condensation polymers biodegrade?

Identify two functional groups that could undergo this type of reaction.

Petroleum is a non-renewable resource from which a wide range of useful polymers is currently produced. Current polymer research is looking at renewable plant material as a potential source of monomers.

Two monomers obtained from plants are shown.

Draw the displayed formula of the repeat unit of a polymer using both monomers.

Monomers obtained from plant sources do not usually form addition polymers. Suggest why this is.

What would be the main force between the chains in each polymer?

Y

Z

Which is likely to be the more hydrophilic of these two polymers? Explain your answer.

Complete the table placing a tick ($\checkmark$) in the correct column to indicate in which process each substance could be used.

Proteins and DNA form different helical structures. Briefly describe the bonding that maintains the shape of each of these helical structures.

protein

DNA

Describe the differences in bonding in the primary and tertiary structures of proteins. Your answer should include reference both to the nature of the bonding and the types of amino acid causing it.

Draw a section of the polymer of propenoic acid showing two repeat units.

By what type of chemical reaction is this polymer formed?

By what type of bonding is water held on the polymer?

Suggest and explain how the difference in the structure of this polymer compared to one formed only from propenoic acid might affect the water absorbing properties of the polymer.

Suggest a property the polymer should have in order to be used in disposable products.

A variation on the gel used for disposable nappies (diapers) containing more sodium propenoate has been used to treat soils contaminated by heavy metals such as lead ($\text{Pb}^{2+}$) and cadmium ($\text{Cd}^{2+}$). Suggest why the gel is effective.

By what type of chemical reaction are the cross-links in this polymer formed?

It is important that the gel should be easily washed out of hair. What is it about the structure of the polymer that allows this to happen?

Complete the table by placing a tick ($\checkmark$) in the correct column to indicate in which process each substance could be used.

Describe the bonding between the two strands in DNA and state which part of each strand is joined by it.

How does the strength of this bonding relate to the mechanism of the replication of DNA?

Some diseases are caused by changes in the structure of proteins. Explain the genetic basis of these changes.

Draw the structure of the monomer used in the polymer chains.

State the type of polymerisation used to form these chains.

Draw the structure of the molecule used to cross-link the polymer chains.

During the cross-linking, a small molecule is formed as a by-product. Identify this molecule.

Once a hydrogel has absorbed water, it can be dried and re-used many times.
Explain why this is possible, referring to the structure on the opposite page.

The amount of cross-linking has little effect on the ability of the gel to absorb water. Suggest why this is the case.

Suggest one property of the hydrogel that will change if more cross-linking takes place. Explain how the increased cross-linking brings about this change.

Complete the table placing a tick ($\checkmark$) in the correct column to indicate in which process each substance could be used.

Proteins and DNA form different helical structures. Briefly describe the bonding that maintains the shape of each of these helical structures.

protein ...............................................................................................................................

DNA ..................................................................................................................................

Describe the differences in bonding in the primary and tertiary structures of proteins. Your answer should include reference both to the nature of the bonding and the types of amino acid causing it.

Draw a section of the polymer of propenoic acid showing two repeat units.

By what type of chemical reaction is this polymer formed?

By what type of bonding is water held on the polymer?

Suggest and explain how the difference in the structure of this polymer compared to one formed only from propenoic acid might affect the water absorbing properties of the polymer.

Suggest a property the polymer should have in order to be used in disposable products.

A variation on the gel used for disposable nappies (diapers) containing more sodium propenoate has been used to treat soils contaminated by heavy metals such as lead ($\text{Pb}^{2+}$) and cadmium ($\text{Cd}^{2+}$). Suggest why the gel is effective.

By what type of chemical reaction are the cross-links in this polymer formed?

It is important that the gel should be easily washed out of hair. What is it about the structure of the polymer that allows this to happen?

Explain with the aid of sketches why the presence of side-chains causes a difference in density in poly(ethene).

By reference to the type of bonding between the poly(ethene) chains, explain why LDPE has a lower melting point that HDPE.

Polymerisation can take place by two different methods depending on the monomers involved. The two methods are addition and condensation.

Give two differences between the methods.

1. .......................................................................................................................................

2. .......................................................................................................................................

Suggest how this polymer conducts electricity.

What is the empirical formula of this polymer?