5.2 Polymers
How do we make Polymers?
Alkenes can be used to make polymers, such as poly(ethene) and poly(propene), through a process known as polymerisation. This involves joining many small alkene molecules (monomers) to form very large molecules (polymers). Let’s take the example of poly(ethene). Poly(ethene) is the joining up of many ethene molecules. The ethene monomers are forced over a catalyst at high pressure and poly(ethene) is created (note: a detailed knowledge of how polymerisation works is not required for the exam).
We would get poly(propene) if we used propene monomers instead of ethene monomers.
Alkenes can be used to make polymers, such as poly(ethene) and poly(propene), through a process known as polymerisation. This involves joining many small alkene molecules (monomers) to form very large molecules (polymers). Let’s take the example of poly(ethene). Poly(ethene) is the joining up of many ethene molecules. The ethene monomers are forced over a catalyst at high pressure and poly(ethene) is created (note: a detailed knowledge of how polymerisation works is not required for the exam).
We would get poly(propene) if we used propene monomers instead of ethene monomers.
Polymers Uses
Polymers have many different uses and the use depends on what they have been made from and the temperature and pressure that the polymer was exposed to during polymerisation.
Poly(ethene) is used to make plastic bags because it is light and stretchable. Scientists are developing new polymers all of the time in areas such as, packaging, waterproof coatings for fabrics, dental polymers for tooth fillings, wound dressings, hydrogels and smart materials (with shape memory functionality, such as a memory foam mattress).
However, many polymers are not biodegradable, meaning that they cannot be broken down by microbes and this leads to problems to do with waste disposal. If you dispose of them in a landfill site, they will still be there for many years. One way to solve this problem is to try and reuse the good made out of polymers. The UK government has imposed a 5p charge for plastic bags to discourage their use and encourage individuals to reuse olds bags/ use a bag for life instead. Another way to deal with the biodegradable issue is to make the products out of corn starch as they would then be biodegradable. Some plastic bags are already being made out of corn starch.
Polymers have many different uses and the use depends on what they have been made from and the temperature and pressure that the polymer was exposed to during polymerisation.
Poly(ethene) is used to make plastic bags because it is light and stretchable. Scientists are developing new polymers all of the time in areas such as, packaging, waterproof coatings for fabrics, dental polymers for tooth fillings, wound dressings, hydrogels and smart materials (with shape memory functionality, such as a memory foam mattress).
However, many polymers are not biodegradable, meaning that they cannot be broken down by microbes and this leads to problems to do with waste disposal. If you dispose of them in a landfill site, they will still be there for many years. One way to solve this problem is to try and reuse the good made out of polymers. The UK government has imposed a 5p charge for plastic bags to discourage their use and encourage individuals to reuse olds bags/ use a bag for life instead. Another way to deal with the biodegradable issue is to make the products out of corn starch as they would then be biodegradable. Some plastic bags are already being made out of corn starch.