Describe two general approaches to toughening an amorphous polymer. Why do they work?

Differentiate between molecular structures and behaviours of thermoplastic and thermosetting polymers. Give one example of each type.

The density difference between low and high-density polyethylene is a result of the difference between branching in the polymer structures at the molecular level. Which of these two polymers tend to be more flexible and is used for lids of containers such as butter tubs?

The heat of fusion of polyethylene is approximately 7.7 kJ/mol, and the corresponding entropy is 19 J mol-1 K-1. Use these data to estimate the melting point of polyethylene.

Explain the difference between addition polymerization and condensation polymerization.

7. The polymer polystyrene can be drawn in its long form in the two ways shown below. Circle/highlight the repeating motif in this polymer. (See Question 13.3 on page 394 for an example of this type of problem.) H H H C -C ·C C fuluhun H H H H H H H C C H H H C6H5 C H H H C C C6H5 C6H5 H C6H5 C C6H5 H H C C C H H C6H5 H C -CH₂-CH-CH₂-CH-CH₂-CH-CH₂-CH-CH₂-CH-CH₂-CH-CH₂-CH-CH₂- H C6H5

Which representation(s) show polymer structures that are likely to result in rigid, hard materials and those that are likely to result in flexible, stretchable, soft materials?

How does crosslinking change the properties of polymer?

Polymers that can conduct electricity are called conducting polymers. Some polymers can be made semiconducting; others can benearly metallic. Polyacetylene is an example of a polymer that is a semiconductor. It can also be doped to increase its conductivity.Polyacetylene is made from acetylene in a reaction that looks simple but is actually tricky to do:H—C≡ C— HAcetylene [— CH=CH— ]n Polyacetylene(a) What is the hybridization of the carbon atoms, and the geometry around those atoms, in acetylene and in polyacetylene?(b) Write a balanced equation to make polyacetylene from acetylene.

a which of the following monomers could form an addition polymer? O C5 H12 CH3-NH, HỌ–CH2–CH(CH3)—OH O C₂H3 CN Submit