Problems Created By Synthetic Polymers (Plastics)
Plastic refers to a material that can be moulded into any shape without breaking, and this is true for synthetic polymers. Synthetic polymers are therefore usually known as plastics.
Properties of plastics
- usually electrical insulators
- usually thermal insulators
- usually unreactive to air, water, acids, or other chemicals which makes them usually safe for storing things in such as food.
- less denser than wood, or stone, or glass, or most metals.
- usually strong in tension because their long molecules are attracted to each other.
It is because of all these properties that plastics officially replaced materials such as metals, glass, paper and wood as well as for natural fibres such as cotton and wool for household and industrial use. We are in the plastic age right now.
Problems created by plastics
However, every great development comes with its own set of problems. Plastics have created a new waste management headache. One of their best properties creates their biggest problem, their unreactivity. Plastics do not break down or rot away. In fact, most of the plastic wastes created 5 decades ago are still around and are likely to still be here 5 more decades from now. Much of the plastic waste has been used to landfill disused quarries, but these sites are getting harder and harder to find.
Polythene creates the biggest waste disposal problem since it is the most used plastic in the world, due to its use in plastic bags and food packaging. It is estimated that more than 5 trillion polythene bags are manufactured every year and most are used only once or twice, before being discarded.
Plastic bags lying around creates many environmental problems, for example:
- they choke birds, fish and other animals that try to eat them thinking its food. If swallowed, they fill up the animals’ stomachs and since they cannot be digested, the animals starve to death.
- they clog up drainage and sewers systems, leading to flooding.
- they collect in rivers and disrupt the movement of fish.
Solving the problems of plastic disposal
- Incinerating the plastic waste to generate heat for heating purposes and for thermal power plants. However, incineration creates more because the combustion process produces toxic gases.
- Recycling the plastic bags to produce more useful products.
- Creating biodegradable and photodegradable plastics. Common degradable plastics include biodegradable plastics which are broken
down by bacteria, as well dissolve in water.
Recycling plastics is a way of reducing plastic waste. For example, some plastics are melted down and made into things like new plastic bags, soles for shoes, and fleeces. Some plastics are melted, cracking their long chains, to make small molecules that can be polymerised into new plastics. When recycling, the plastics are first separated according to their plastics. They are then washed, sorted and ground into small pellets. These pellets can then be melted and remoulded. For example, recycled soft drinks bottles made from PET are used to make fleece clothes.
Besides recycling, some plastics are burned, and the heat produced is used to produce electricity. Only a small percentage of plastic waste is reused in this way, because the burning gives off poisonous gases and gases that contribute to acid rain.
Using degradable plastics is another solution to the waste disposal headache. Biodegradable polythene contains additives such as starch that bacteria can feed on. Other types degradable plastics include photodegradables that break down in sunlight. The use of degradable plastics is becoming popular as people start to understand the issues related to the disposal of plastics as a result of their non-biodegradability.