In the context of polymers, what does the term "crosslinking" describe? What will happen to the properties of the polymer when it is crosslinked.

Using content from your lecture notes only, answer the following:

(a) Describe the general mechanical properties that you would expect to see in an amorphous thermoplastic polymer compared to semi-crystalline or crystalline polymers (i.e. what mechanical properties will be different between the two groups, and how will they be different?). Cover a range of different mechanical properties that we have discussed in class.

(b) Describe the types of bonding and types of structures that are generally present in these materials.

(c) For each of the properties you discusse above,  discuss the mechanisms of ductility. In your answer explain how the property is controlled at the atomic-scale and/or micro-scale.

A material is tested in tension and found to have the following stress-strain graph. The coordinates of point B on the graph are (0.25, 56). The elastic modulus of the material is 7.8 GPa.

HInt - approximate the number of squares under the curve.

Calculate the toughness of the material. Give your answer in MJ/m³ (equivalent to MPa) to at least 2 significant figures

A material is tested in tension and found to have the following stress-strain graph. The elastic modulus of the material is 7.8 GPa.

The coordinates of point B on the graph are (0.25, 56). These will help you determine the scale of the graph.

Accurately calculate the ductility of the material. Give your answer as a % to 2 decimal places.

Write your workings on a sheet of paper and upload an image of these at the end of the test. Write your final answer in the text box.

A piece of steel with elastic modulus of 200 GPa and yield strength of 500 MPa is placed under a stress of 300 MPa. Calculate the %strain that occurs in the material. Show your working.

Concrete typically breaks before undergoing plastic deformation. An engineer would refer to this material property as .... Provide and explanation for this behaviour from what you have leant in your lectures.

The most important type of bond in gold is:

Polymers typically contain large quantities of which element along their backbone?

What crystal lattice is Aluminium metal typically found in?

Choose the best answer:

Dislocations are...