Plastics are can be divided in to Categories like: Natural Plastic, Semi Synthetic Plastic, Synthetic Plastic, Thermoplastic, Thermosetting Plastic

Natural Plastics – these are naturally occurring materials that can be said to be plastics because they can be shaped and molded by heat – as it comes from Greek word plasticos, which means to be able to shape and mold by heat. An example of the natural plastic is Amber – which is in a form of fossilised pine tree resin and often used in jewelry manufacture.

Semi-Natural Plastics – these are made from naturally occurring materials, that have been modified or changed by mixing other materials with them. An example of this is Cellulose acetate, which is reaction of cellulose fiber and acetic acid to make cinema films.

Synthetic Plastics – these are materials that are derived from breaking down or ‘cracking’ carbon base materials, usually Crude Oil, Coal or gas so that their molecular structure changes. These is generally done in Petrochemical – Refineries, under heat and pressure and is the first of manufacturing processes that is required to produce most of our present day, commonly occurring plastics.

Synthetic and Semi Synthetic plastics can be further divided in to two other categories. These two categories are defined by the ways in which different plastics react when heated.

Thermoplastics – these are plastics that can be softened and formed using heat and when cool, will take up the shape that they have been formed into. But if heat is re-applying, they will soften again. Example of Thermoplastics are Acrylic and Styrene, probably the most common plastics found in school workshops.

Thermoplastics are : Polyethylene (PE) – Polypropylene (PP) – Polystyrene (PS) – Polyvinyl Chloride (PVC) – Polyamide (Nylon) – Polyester – Polyurethane – Acrylonitrile Butadiene Styrene (ABS) – Polyoxymethylene (POM)(Acetal)(Polyacetal)

Polyformaldehyde is also POM Engineering Plastic.

Thermosetting Plastics – these are plastics that softened when heated and can be molded when soft and when cool, it will set into the molded shape. But if heat is re-applying, it will not soften again, they are permanently in the shape that they have been molded into. Example of Thermosetting Plastics are Polyester Resins, used in glass reinforced plastic work and melamine formaldehyde used in the manufacture of Formica for Kitchen and Furnitures.

Polymers is the general term for all plastic material and means that they are organic and carbon base compound whose molecules are linked together in to long chain pattern.