Different Types of Plastic
Thermoplastics either have a linear or a branched structure. That is what makes them elastic at ordinary temperatures. After they have been moulded you are able to deform them without destroying their structure but in contrast to elastomers they will stay that way. Also, they start to melt at about 120°C to 180°C.
Polythylene is transparent and resistent to several acids. It starts to melt at 80°C and is instable to ultraviolet light. You can find this sub-division of plastic in bottles, packaging material and insulation material.
It has the same characteristics as PE, but it withstands higher temperatures (>100°C). PP is used for the interior of cars, in surgery and in the textile industry.
Polyvinyl chloride; PVC
This type of plastic is very long lasting and finds widespread use in various areas of life. It is used for cabling application because it has very good electrical isolation properties. PVC is waterproof. It can be flexible or rigid, according to its formulation.
Polyethylene terephthalate; PET
Like polythylene PET is transparent. It is not resistant to acids and it deforms at higher temperatures. The problem of PET is that a part of the used materials are recycled plastics and it is not sure what phthalates are contained. Additionally, PET releases poisonous acetaldehyde. PET is used for plastic bottles but also for textile fibres.
Thermosets have a molecular structure – they are like one big molecule. Also, they are the opposite of thermoplastics because if they become warm, they will degrade. Additionally, thermosets are not flexible or elastic – if you try to deform them they will break. This kind of plastic is used for light switches or head protection.
Elastomers are very elastic and flexible – they can be stretched to about twice their lenght. They don not melt and most of them can be deformed over and over again because they return to their original shape. They are used for sythetic rubbers, tires and rubber bands.
Author: Judith Seil
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