Reinforcing and stiffening
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:
- Pulling force exerted by each end of an object such as a string or rope. - a pulling force
- Being squashed. - a pushing force
- A bending force is applied at an angle causing a material to be in compression and tension at the same time. - forces at an angle to the material
- A twisting force. - a twisting force
- A force across a material, eg scissors cut by applying a shear force. - forces acting across the material
It is very difficult to generalise on the properties of A polymer is a large molecule formed from many identical smaller molecules (monomers). Polymers can be natural or synthetic. Plastics are long chains of polymers. as there are so many. Below are four commonly used polymers:
| Common polymer | Shorthand | Common use |
| Polyethylene terephthalate | PET | Plastic water bottles |
| Polyvinyl chloride | PVC | Plastic toys, cling film, blister packs |
| Low density polyethylene | LDPE | Bread bags |
| Expanded polystyrene | EPS | Packaging and coffee cups |
| Common polymer | Polyethylene terephthalate |
|---|---|
| Shorthand | PET |
| Common use | Plastic water bottles |
| Common polymer | Polyvinyl chloride |
|---|---|
| Shorthand | PVC |
| Common use | Plastic toys, cling film, blister packs |
| Common polymer | Low density polyethylene |
|---|---|
| Shorthand | LDPE |
| Common use | Bread bags |
| Common polymer | Expanded polystyrene |
|---|---|
| Shorthand | EPS |
| Common use | 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 A person who develops materials using the principles of science and maths.. It is important to understand the characteristics of each polymer available to see if it is fit for the intended purpose.
