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Plastics are often frowned upon. This is because people often think of them as cheap and not aesthetically pleasing.

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Introduction

Plastics Plastics are often frowned upon. This is because people often think of them as cheap and not aesthetically pleasing. However they come in many different forms and often look very nice. Obviously there are types that do give the product a bad name. Mainly the cheap toys that are produced in the far east. This is not right and plastics should be seen as a real alternative and be able offer a huge amount of uses for this product. Polymers Polymers such as rubber, plastics and adhesives are organic structures. They can be natural, like amber and shellac, modified natural materials, like cellulose and casein, or synthetic, like nylon and polypropylene. ...read more.

Middle

When subjected to pressure, thermoplastics can deform in two ways. Elastic deformation occurs in which the initially curled long chains stretch out and this deformation is recovered when the pressure is removed. At higher temperatures or pressures, viscous or plastic deformation occurs in which the secondary bonds weaken and allow the molecular chains to slide over each other. This weakening of the bonds at higher temperatures means that thermoplastics are easy to cast or form. Thermosets Thermoset polymers are formed by a condensation reaction which forms strong, primary cross-linking bonds between adjacent polymer chains, giving them a rigid three-dimensional structure in which the atoms cannot move easily. Heating helps this cross-linking process and so the polymer hardens as it is heated. ...read more.

Conclusion

The tool costs are much lower than for presswork and it is possible to get high-quality finish, which is difficult when pressing SNICs, for example. One disadvantage is that the stress levels required to deform the material cannot be too high and this limits the materials which can be used and the shapes that can be generated. Bending Plastics can be bent in many ways. By using heat the bonds in the plastics become separated and malleable. This enables the plastic (usually in sheet form) to be bent. Both thermo and thermosetting plastics can be bent however thermosetting plastics can not then be reformed. If the plastic gets too hot however it will begin to deform. The structure and the appearance of the plastic will therefore change. ...read more.

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