Plastics are derived from natural, organic materials such as cellulose, coal, natural gas, salt and, of course, crude oil. Crude oil is a complex mixture of thousands of compounds and needs to be processed before it can be used. The production of plastics begins with the distillation of crude oil in an oil refinery. This separates the heavy crude oil into groups of lighter components, called fractions. Each fraction is a mixture of hydrocarbon chains (chemical compounds made up of carbon and hydrogen), which differ in terms of the size and structure of their molecules. One of these fractions, naphtha, is the crucial compound for the production of plastics.
Two main processes are used to produce plastics – polymerisation and polycondensation – and they both require specific catalysts. In a polymerisation reactor, monomers such as ethylene and propylene are linked together to form long polymer chains. Each polymer has its own properties, structure and size depending on the various types of basic monomers used.
There are many different types of plastics, and they can be grouped into two main polymer families:
Thermosets (which never soften once they have been moulded).
Since the dawn of history, humankind has endeavoured to develop materials offering benefits not found in natural materials. The development of plastics started with the use of natural materials that had intrinsic plastic properties, such as shellac and chewing gum. The next step in the evolution of plastics involved the chemical modification of natural materials such as rubber, nitrocellulose, collagen and galalite. Finally, the wide range of completely synthetic materials that we would recognise as modern plastics started to be developed around 150 years ago:
Polyvinyl chloride (PVC) was first polymerised between 1872.
Since Baekeland’s creation, many new plastics have been realised and developed, offering a huge range of desirable properties, and you will find them in every home, office, factory and vehicle.
ADPLAST offers a wide range of additives that give unique characteristics to the following thermoplastics: