Biodegradable and Non-biodegradable Polymers — Definition
Definition
Imagine tiny building blocks, called monomers, joining together in a long chain to form a giant structure. This giant structure is what we call a polymer. Think of a pearl necklace where each pearl is a monomer, and the whole necklace is a polymer. Now, when we talk about polymers, especially in the context of our environment, we often categorize them based on how they behave when they are discarded. This leads us to two main types: biodegradable and non-biodegradable polymers.
Biodegradable polymers are like materials that know how to 'disappear' naturally. When you throw away something made of a biodegradable polymer, it doesn't just sit there forever. Instead, tiny living organisms, like bacteria and fungi, which are abundant in soil and water, start to 'eat' or break down these polymers.
They use special chemicals called enzymes to chop the long polymer chains into smaller, simpler molecules. Eventually, these smaller molecules can be reabsorbed into the natural cycle, turning into things like water, carbon dioxide, and biomass – essentially, they return to nature without causing harm.
This process is similar to how a fallen leaf eventually decomposes and becomes part of the soil. The key characteristic here is that they break down into harmless substances within a reasonable timeframe, often under specific conditions like those found in compost piles or wastewater treatment plants.
Examples include some bioplastics used for packaging or medical stitches that dissolve in the body.
On the other hand, non-biodegradable polymers are the stubborn ones. These polymers are built in such a way that natural processes and microorganisms find it extremely difficult, if not impossible, to break them down.
Their chemical bonds are very strong and resistant to enzymatic attack or simple hydrolysis. So, when you discard a non-biodegradable polymer, like a typical plastic bottle or a plastic bag, it remains intact in the environment for a very, very long time – sometimes hundreds or even thousands of years.
They accumulate in landfills, pollute our oceans, harm wildlife, and contribute to significant environmental problems. Most of the conventional plastics we use daily, such as polyethylene, polypropylene, PVC, and polystyrene, fall into this category.
Understanding this distinction is crucial for developing sustainable materials and managing waste effectively, which is a major global challenge today.