Subject : Basic Technology
Class : Basic 9 / JSS 3
Term : 1st Term / First Term
Topic: Production of Materials – Plastics and Rubber
1. Methods of Producing Plastics
2. Methods of producing Rubber
There are many ways from many ways of making plastics from molten materials. The choice of methods depends on the plastics product to be made and its use. A popular method of making thermoplastics is injection moulding. The resins in required colours, are fed into the hopper.
The resins are heated in the heating chamber between the hopper and the mould. The right amount of the molten material is then forced by the plunger into the mould. The plastic article is formed as it is forced into the mould. The article stays in the mould until it is completely cool; then it is removed. Plastic products such as valve and the air-make grill of an air conditioner nylon hair comb are made by the injection moulding method.
Method of Producing Rubber – Natural and Chemical
We already know that there are two types of rubber – natural rubber and synthetic rubber. Natural rubber is made from the latex obtained from rubber trees, while synthetic rubber is obtained from petroleum products. In each case the resulting high quality rubber is too hard to be processed easily. So, the first step in processing rubber is to break it down, to make it smoother and more malleable, in order to get an even mixture, we blend the rubber with certain chemicals and softeners. Carton black (fine carbon obtained from wood, bones or plants) is added in order to make the rubber product stronger. After thorough mixing, the rubber is then ready to be formed. Rubber products are formed by processes similar to those used in making plastics.
• Briefly explain two types of rubber
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