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Everyone has probably noticed that when we dump household solid wastes at dumpsites, some of the waste disappears after a few days (biodegradable wastes), but some of the waste begins to accumulate at the site (non-biodegradable wastes). Biodegradable polymers are polymers that can decompose in a matter of days due to the action of microorganisms. Polymers that are not decomposed by microorganisms are referred to as non-biodegradable polymers. To combat these diseases and infections, we have begun to employ environmentally friendly synthetic polymers. This type of polymer has functional groups that are similar to those found in biopolymers. They can be created synthetically by combining molecules of ester, anhydride, and amide. These molecules connect to one another.
Overview
Biodegradable materials decompose easily due to the actions of bacteria, fungi, and other living organisms. Biodegradable substances are commonly found in everyday life, such as food waste, tree leaves, and grass clippings. Plant materials are typically biodegradable. Biodegradable materials are simple to work with. Most communities encourage people to compost their waste and then use it as an organic-rich material in soil known as humus. As a result, gardening is encouraged. This procedure is known as composting.
Non-biodegradable substances could not be cracked down by natural organisms and thus may cause pollution. These wastes are difficult to deal with. It cannot be broken down by naturally occurring agents and can therefore remain on the earth’s surface for many years. The majority of inorganic substances are non-biodegradable.
Biodegradable and non-biodegradable polymers
Presently, polymers are widely used in our daily lives. Many polymers, however, are highly resistant to degradation and contribute to the accumulation of polymer solid waste. These solid wastes, as they accumulate, pose a serious threat to the environment and remain undecomposed for an extended period of time. As the use of polymers grows, the disposal of waste from these products becomes a serious issue. These are non-biodegradable polymers, and plastics are the most common application for non-biodegradable polymers.
As a result of these issues, scientists discovered biodegradable polymers. Biodegradable polymers, unlike aliphatic polyesters, are easily degraded by microorganisms, resulting in less waste accumulation and causing less harm and pollution to the environment.
Biodegradable polymers
Biodegradable polymers are those that decompose easily in nature through aerobic and anaerobic processes. Biodegradable polymers can be placed in a bioactive environment, where they are degraded by the enzymatic actions of microorganisms such as fungi, algae, and bacteria. Chemical hydrolysis, for example, is a non-enzymatic process that can break down the chain of biodegradable polymers.
Biodegradable polymers typically have ester, amide, or ether bonds. Biodegradable polymers can be divided into two broad categories based on their structure and synthesis. Agro-polymers, or those derived from biomass, are one of these groups. The other type of polymer is biopolyester, which can be derived from microorganisms or synthesised from naturally or synthetically derived monomers.
Polysaccharides, such as starches found in potatoes or wood, and proteins, such as animal-derived whey or plant-derived gluten, are examples of agro-polymers. Polysacharides are made up of glycosidic bonds that take a hemiacetal of a saccharide and bind it to an alcohol via water loss. Proteins have been made up of amino acids, which have a variety of functional groups. Condensation reactions bring these amino acids back together to form peptide bonds, which contain amide functional groups. Polyhydroxybutyrate and polylactic acid are two examples of biopolyesters.
Despite the fact that biodegradable polymers have a wide range of applications, there are some characteristics that they all share. All biodegradable polymers should be stable and durable enough to be used in their specific application, but they should degrade easily when discarded. Polymers, particularly biodegradable polymers, have extremely strong carbon backbones that are difficult to break, so degradation frequently begins at the end-groups. Because degradation begins at the end, a large surface area is common because it allows easy access for the chemical, light, or organism.
Polyesters are one of the most important and well-studied groups of biodegradable polymers. Direct condensation of alcohols and acids, ring-opening polymerizations (ROP), and metal-catalyzed polymerization reactions are all methods for producing polyesters. The need to continuously remove water from this system in order to drive the equilibrium of the reaction forward is a significant disadvantage of step-wise polymerization via condensation of an acid and an alcohol. This could result in harsh reaction conditions and long reaction times, resulting in a wide dispersity. Polyesters can be synthesised from a wide range of starting materials, and each monomer type gives the final polymer chain unique characteristics and properties. A ROP of cyclic dimeric glycolic or lactic acid produces α-hydroxy acids, which polymerize to form poly-(α-esters). To begin the polymerization of polyesters, organometallic initiators such as tin, zinc, and aluminium complexes can be used. Poly(β-esters) and poly(β-esters) can be synthesised using the same ROP or condensation methods as poly(γ-esters). Metal-free processes involving bacterial or enzymatic catalysis in polyester formation are also being investigated.
Biodegradable polymers examples
Poly β-hydroxybutyrate – co-β-hydroxy valerate (PHBV):
It is really made by combining 3-hydroxybutanoic acid and 3-hydroxypentanoic acid, with monomer units linked by ester bonds. This subdivides into carbon dioxide and water. It is brittle and can be used to make medicines, bottles, orthopaedic devices, packing material, and other items.
Polyglycolic Acid (PGA):
Polyglycolic acid is produced by chain polymerization of cyclic dimers of glycolic acid. This is the most basic linear aliphatic polymer, and it is used in drug delivery, orthopaedic operations such as screws and nails, and other applications.
Nylon-2-Nylon-6:
Nylon-2 Nylon-6 is indeed an alternating polyamide copolymer made from glycine and aminocaproic acid that is used to make toothbrush bristles and musical instrument strings.
Non-biodegradable polymers
Dangerous plastics, aluminium cans and bottles, scrap metal, foam styrol, tyres, paints, and various chemicals are among the non-biodegradable items. Natural processes have no effect on these objects, and they cannot be disassembled or degraded after thousands of years. They are extremely hazardous to the environment and contribute significantly to solid waste, which is harmful to human health.
One of the really serious issues with these polymers in recent years has been the accumulation of tonnes of waste products in the ocean and on land. These polymers are polyethene and polypropylene, which are designed to be long-lasting. This means that these polymers are difficult to decompose and provide strength and durability to the products that use them.
Furthermore, plastics, which we see every day, are frequently soiled by food and other biological substances, making physical recycling of these materials difficult and generally undesirable.
More than 80% of non-biodegradable plastic packaging is only used once and then discarded.
As a result, it generates waste that ends up in the oceans and on land, disrupting the natural balance of wildlife and nature. Even so, these polymers have a wide range of applications, but in order to protect nature and its resources, we must consider decomposable alternatives and avoid creating a hazard by discarding them after use.
Non-biodegradable polymers examples
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Polyethene
They are of three kinds, namely-
- Linear high-density polyethene (HDPE)
- Branched low-density polyethene (LDPE)
- Ultra-high molecular weight polyethylene(UHMWPE)
They have quite a high strength and density and are widely used.
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Teflon
Teflon, also known as tetrafluoroethylene, is a synthetic fluoropolymer of tetrafluoroethylene that is less reactive and thus used in cooking wares, aerospace wiring, and other applications.
FAQs
What are Polymers?
Polymers seem to be macromolecules made up of repeated subunits known as monomers. Polymers can be both synthetic and natural. Natural polymers include silk, wool, rubber, hemp, and others, while synthetic polymers include polyvinyl chloride, polypropylene, PVB, nylon, and others.
How are synthetic non-biodegradable polymers used in medicine?
Synthetic Non-biodegradable polymers have been commonly used in the production of a wide range of medical devices, including disposable supplies, implants, drug delivery systems, and tissue engineering scaffolds. The use of polymers as biomaterials has the advantage of being easily manufactured.
Why are synthetic fibres considered to be non-biodegradable?
Synthetic fibres were indeed man-made fibres that are manufactured artificially. Plastic and other synthetic fabrics, such as rayon, nylon, or acrylic, for example, are not mixed into the soil and thus have serious consequences.
