Forces act on materials all the time - even if a material appears stationary it still has a force acting on it. There are five terms used to describe what type of force can act on a material:
It is very difficult to generalise on the properties of polymers as there are so many. There are seven types of plastic - six are common and are used for everyday objects, and the last type (not listed below) covers the substantial variations remaining that are not common.
|Common polymer||Shorthand||Common use|
|Polyethylene terephthalate||PET||Plastic water bottles|
|High density polythene||HDPE||Fabric conditioner bottle|
|Polyvinyl chloride||PVC||Plastic toys, cling film, blister packs|
|Low density polythene||LDPE||Bread bags|
|Polypropylene||PP||Yogurt pots and pen lids|
|Polystyrene||PS||Packaging and coffee cups|
Each polymer type from the table above will cope with a force in a different way. If a polymer doesn’t withstand the force needed, a new type of polymer could be created by a chemical engineer. It is important to understand the characteristics of each polymer available to see if it is fit for the intended purpose.