Technology Unit - 4 Practical Excercises

Excercise 1: Identifying plastics, processing methods and varying forms that plastics exist in.

Aim: to examine a number of plastics raw materials, plastics artefacts and related materials to determine:

• what they are
• what processing method was used to produce them
• and to examine the variety of forms into which some resins can be processed.

Procedure:
a) Write down the name of the plastic resin used.
b) Write down the name of the artifact(s)
c) Observe and record the range of forms
d) Use the notes provided to determine the processing method used to manufacture the item. Make sure that you work systematically.

1. Read the notes on “processing methods”
2. There are a number of stations in this practical exercise. You are to move around to each station in turn.
3. At each station you are to:

Note: you could be evaluated on your understanding of this work.

Excercise 2: Observation of some simple properties of some plastic materials.

Aim: To become familiar with the properties demonstrated by some plastic materials and to have some hands on experiences with plastics.

Procedure: Students rotate around in station in order - spending a defined time at each station. The students stay at each station until they have completed the exercise and then all students move on the teacher’s instruction in a clockwise or anti-clockwise direction.

Possible Activities:

1. Effect of heat on Alkathene (polythene or polyethylene) pipe. (Flexible black sprinkler hose) and on other plastic piping such as rigid PVC water piping. (Caution — fumes)
2. Memory quality of plastics. Plastic tray in boiling water.
3. Yoghurt Pot in Oven.
4. Cutting Polystyrene - with hot wire. (Caution — flammable gas)
5. Expanding unexpanded Polystyrene beads.
6. Effect of heat on shrink film.
7. Shrink sleeving.
8. Testing a Supermarket plastic bag to destruction. (Demonstrated at seminar)
9. Testing a sealable plastic bag for leaks (“zipper” plastic bag).
10. Establishing the strength of plastic film.
11. Tests for resistance to puncture.
12. Cling wrap permeability compared to cellophane permeability.
13. Plastic powder coating of metal.
14. Fibre optic cable - with plastic coating - transmission of light.
15. Examination of synthetic fibres Nylon/acrylic/rayon/polypropylene — under the microscope.
16. Oasis - Water Uptake - Thermoset Plastic.
17. PVC Glue - Thermoset Plastic - Effect of reinforcing.
18. Polyethylene Powder moulding in an oven.
19. Epoxy Resin moulding Thermoset plastic. (Demonstrated at seminar)
20. Araldite Glueing Thermoset plastic.
21. Determining the hardness of a number of plastics - and rank them according to hardness.
22. Determining the density of a number of plastics.
23. Examining the effect of solvents on a range of plastics.
24. Pliability of Plastics.
25. Simple thermoforming.
26. Measuring thickness of film.
27. Comparisons of the effect of heat on a number of plastic films.

Safety note: When plastics are subjected to extreme treatments such as burning or strong heat irritating gases may be emitted. It is essential that these exercises are carried out in a well ventilated room. Exercises such as cutting polystyrene with a hot wire or expanding unexpanded polystyrene beads should be carried out in a fume cupboard — or next to an open window.
 

Excercise 3: The role of plastics in cars to conserve energy

Introduction: Over the last 35 years there has been a progressive replacement of metal parts by plastic ones in motor cars to decrease the weight of cars. This reduction in weight results in significant fuel savings as less energy is needed to move a lighter vehicle. Experts estimate that there are approximately 1,000 plastics parts of all sizes in the average car - or about 110kg of plastics (APME,99).

Average amounts of plastics in cars is shown in the data below.
 

Readings:

• Evolution is dead, long live innovation: New perspectives for plastics in cars
• Web site http://www.plastics-car.com/s_plasticscar/
   

1. Read one of the above documents and write a brief summary of the future impact of emerging plastics technologies and their impact on energy conservation.
2. Plot the data provided on a line graph to show the trend in plastic use in cars.
3. Name 5 items in cars that are made from plastic.
4. It is estimated that plastics use in car manufacture has increased by 1.5 % per year since 1985. Calculate what the amount of plastic in cars would be for each of the years from 1999 onwards and write those somewhere on your own paper.*
5. Add this information to your line graph
6. It is estimated that a 1000kg car containing l00kgs of plastics uses 4% less fuel than if only metals were used. If a car uses 2000 litres of fuel per year costing 90c per litre how much money is saved through the use of plastics.*
7. Assume that an extra 1% of fuel is saved for every additional 25kgs of plastic that exists with a car. Calculate how much money would be saved per year by a car in 1995, based on the amount of fuel used as above.*
8. Apart from the fuel savings produced by having a lighter vehicle, what other benefits are there in using plastics instead of steel in cars?

* source: Society of Plastics Engineers.

Excercise 4: Technological Knowledge & Understanding: Use of a Key to Identify Common Plastics

This exercise is designed to develop team work skills, decision making skills, observation skills and technological skills. Keys are common in many different fields of Technology. Above all this exercise is designed to encourage you to become more familiar with a range of plastic materials).

Health & Safety - Note carefully

• Some of the fumes given off from plastics materials are unpleasant and can sometimes cause minor illness.
• Always carry out in a well ventilated room.
• Be careful of dripping molten or burning plastic.
• It is better to use a spirit burner than a bunsen.
• Get your teacher to show you the correct way to smell gases.

Procedure
You will be presented with a number of common plastic items. As well you will need

• a burner
• a beaker
• a pair of scissors
• the key
• a nail and tongs

Work methodically through the key for each plastic in groups of 2 or 3.

Reference: ICI Chemicals