Polymer plastic is primarily made through chemical processes that link small molecules together into long chains.
Creating polymer plastic involves chemically joining together smaller building blocks called monomers. This process forms the long, repeating molecular structures known as polymers, which are the foundation of all plastics.
Two main chemical processes are used to produce polymers for plastic:
Key Processes in Polymer Manufacturing
- Polymerisation: This process involves adding monomers together to form long polymer chains.
- Polycondensation: This process also links monomers, often involving the release of a small molecule, such as water, as a byproduct.
Both polymerisation and polycondensation reactions require specific catalysts to initiate and control the process efficiently. Catalysts help speed up the reaction without being consumed themselves.
The Role of Monomers and Reactors
In a polymerisation reactor, monomers such as ethylene and propylene are linked together to form long polymer chains. Ethylene monomers linked together form polyethylene, a common plastic used in films and bottles. Propylene monomers form polypropylene, used in containers and fibers.
The specific type of monomer used and the process (polymerisation or polycondensation) determine the type of plastic created and its resulting properties, such as flexibility, strength, and heat resistance.
Essentially, raw materials (derived typically from oil, natural gas, or increasingly, biomass) are processed into monomers, which are then reacted in large chemical reactors under controlled conditions with the help of catalysts to create the desired polymer chains. These polymers are then further processed (like melting and shaping) into finished plastic products.
