Question 41 – Properties of materials - Questions

Polymer

Cost (£ per kg)

Tensile strength (MPa)

Melting point (

∘C^{\circ}\text{C}

)

Maximum useable temperature (

∘C^{\circ}\text{C}

)

Alpha

1.80

160

120

Beta

3.20

300

240

Gamma

2.10

250

185

Delta

1.30

140

100

A manufacturer is choosing a polymer to produce sterilization trays for medical autoclaves.

The trays must meet the following criteria:

Safely withstand operating temperatures of up to $150∘C150^{\circ}\text{C}$ .
Have a tensile strength of at least 40 MPa to support heavy surgical instruments.

The physical properties and costs of four candidate polymers are shown in the table below:

Polymer	Cost (£ per kg)	Tensile strength (MPa)	Melting point ( $∘C^{\circ}\text{C}$ )	Maximum useable temperature ( $∘C^{\circ}\text{C}$ )
Alpha	1.80	30	160	120
Beta	3.20	75	300	240
Gamma	2.10	50	250	185
Delta	1.30	22	140	100

Determine, with reasoning, which polymer is the most suitable and cost-effective choice for manufacturing these trays.

Properties of materials