KEY CONCEPTS OF PLASTICS AND TEXTILES

-  Both natural and synthetic fibres can be woven to make a variety of textiles.

- Natural fibres may come from animal sources (wool, silk), plant sources (cotton, linen, esparto, bamboo) and mineral sources (gold, silver and copper fibres).

- Synthetic fibres, such as nylon, polyester, rayon and Lycra, are plastic materials.

(LYCRA)

KEY CONCEPTS OF PLASTICS AND TEXTILES

- Modification techniques use tools and machines to make changes to prefabricated materials, such as sheets, bars or mouldings.
- Examples of these techniques include: measuring - drawing marks and lines - cutting - drilling - filing and sanding - joining.

-  You must always pay special attention to health and safety rules.

KEY CONCEPTS OF PLASTICS AND TEXTILES

- Various industrial techniques can be used to manufacture plastic products, such as: extrusion, calendering, vacuum forming and moulding.

- The main techniques for using moulds are as follows: blow moulding, injection moulding and compression moulding.

(BLOW MOULDING)

KEY CONCEPTS OF PLASTICS AND TEXTILES

-Thermoplastics are usually made from petroleum products. The most common thermoplastics are:

 • Polyethylene terephthalate (PET).

 • High-density polyethylene. 

 • Polyvinyl chloride (PVC). 

 • Low-density polyethylene. 

 • Polypropylene.

 • Moulded polystyrene. 

 • Expanded polystyrene or Styrofoam.

(PET)         

- Thermosetting plastics are made from petroleum products. They include: 

• Polyurethane.

• Bakelite. 

• Melamine. 

• Polyester resins.

(MELAMINE)

- Typical elastomers include rubber and neoprene.

KEY CONCEPTS OF PLASTICS AND TEXTILES

- Plastics consist of long chains of atoms which are mostly composed of carbon.










- Plastics be classified into natural and synthetic plastics.

- The process of manufacturing plastic is called polymerisation.

- Plastic materials are resistant, insulating (against electricity, heat and sound), ductile, malleable, impermeable and light.

- There are three types of plastic recycling processes: chemical and mechanical recycling and energy recovery.

BASIC DEVICES MADE WITH ELECTRONIC COMPONENTS

We can build various devices with the electronic components discussed in the previous section. Here are two examples:
Timers.
 A timer is a device thet operates for a certain period of time and then shuts itself off automatically.

Integrated circuits.
Integrated circuits consist of miniature electronic components, such as transistors, resistors and capacitors.

ELECTRONIC COMPONENTS

Transistors.
They are made from semiconductor materials and have three electrodes called the base, the collector and the emitter.
There are two types of transistor: NPN and PNP.

-When no electrons are flowing through the base, then no electrons can pass from the collector to the emitter. The transistor is in cut off.

- When many electrons are flowing through the base, the route between the collector and the emitter will be completely open. The transistor is in saturation.

- When the flow of electrons through the base is between the cut off and saturation levels, it will be proportional to the flow of electrons between the collector and the emitter. The transistor is in the active region.