Sources and origins
Leo Hendrik Baekeland was the inventor of the first commercial synthetic plastic; it was made from phenol and formaldehyde and known as Bakelite. Since 1907, technology has developed and chemical engineerA person who develops materials using the principles of science and maths. have been able to develop polymerA polymer is a large molecule formed from many identical smaller molecules (monomers). Polymers can be natural or synthetic. Plastics are long chains of polymers. that can be recycled. Polymer-based products are increasingly a part of everyday life, used in many products, from pens to parts for racing cars.
Most polymerA polymer is a large molecule formed from many identical smaller molecules (monomers). Polymers can be natural or synthetic. Plastics are long chains of polymers. are obtained from crude oilMixture of hydrocarbons, mainly alkanes, formed over millions of years from the remains of ancient dead marine organisms. often found deep within the Earth’s crustThe outer layer of the Earth on top of the mantle. and Russia, Saudi Arabia and USA are the major oil suppliers. It is accessed by drilling, which can be a costly and messy process. The oil is heated to break it down and obtain different products through a process called fractional distillationIn fractional distillation a mixture of several substances, such as crude oil, is distilled and the evaporated components are collected as they condense at different temperatures..
Some polymers can be derived from natural sources, such as plants. The most common plant-based polymer used in schools is polylactic acid (PLA)A biodegradable thermoplastic from renewable resources, such as corn starch., which is commonly used in a 3D printer. PLA is obtained from corn starch - the corn is fermentedA process that consumes sugar in the absence of oxygen with the production of acids and gases. to produce lactic acid, which is polymerisedThe joining of monomers to produce a polymer. to produce polylactic acid.
Most polymers are synthetic, meaning they are man-made and have been designed by chemical engineers. Different polymers are created all the time so that the demands of the consumerIn business, a consumer is a person who uses a product and may also buy it. can be met. Polymers fall into two categories:
- thermosettingAlso called ‘thermoset’. Can only be formed once as it cannot be reheated and therefore cannot be recycled. plastic or thermosetAn alternative name for thermosetting polymers.
- thermoformingAlso called ‘thermoplastic’. Can be reformed when heated, and therefore can often be recycled. plastic or thermoplasticAn alternative name for thermoforming polymers.
‘Thermo’ indicates that heat will be involved in the way the polymer is shaped, and ‘set’ means that once the polymer has been set in that shape, heat will not alter the form. Thermoforming plastic, however, can be heated and shaped, then heated and shaped again. These polymers are also often referred to simply as ‘thermoplastics’.
Polymers are a great material for designers and engineers as they have been engineered by humans, meaning it can be easier to predict how they will react in different contexts compared with natural materials.
