What are Biodegradable Plastics?
Plastics are everywhere and are used in almost all areas in the modern-day including in the making of cutleries, packaging and wrapping items, bottles, food containers, clothes, wearable, vehicle parts, electronics, pens, and furniture among many other items. Their wide usage is because of their versatility in 3D modeling, durability, and ease of work within various manufacturing and production processes.
The use of plastics, however, comes with a downside; especially concerning its negative impacts on the environment including landfill and plastic pollution. Plastic materials generally take centuries to breakdown naturally in the environment. The world has witnessed the various environmental problems associated with plastics, advancements have been made towards the manufacture and use of biodegradable plastics.
Biodegradable plastics are those that can decompose naturally in the environment. The makeup structure of biodegradable plastic makes them easily break down by natural microorganisms, giving an end product that is less harmful to the environment.
As such, biodegradable plastics are perceived to be more eco-friendly due to their environmental benefits, which are hard to deny compared to ordinary plastics. To minimize environmental pollution, this type of plastic is undoubtedly a better choice but still comes with its downside. Here, we look at how biodegradable plastics are made, their benefits and problems, and examples of their uses.
How are Biodegradable Plastics Made?
Biodegradable plastics are made in a way that they can breakdown or degrade when exposed to the sun’s ultra-violet radiation, enzymes, bacteria, water, or wind abrasion. They are made from renewable raw materials or all-natural plant or animal materials such as orange peels, corn oil, switchgrass, soybeans, micro-organisms or starch. The industrial processing of biodegradable plastics is similar to the manufacture of ordinary plastic, only that the materials used differ and for bio-degradable plastics; they are the materials that can easily break down or decompose. They are mainly categorized into two
- Bio-plastics; purely made from natural substances such as corn starch. Examples of those made from corn starch include EverCorn and NatureWorks. In their manufacturing process, they save energy and emit less carbon as the plants used already have the same amount of carbon.
- Biodegradable plastics; made from traditional petrochemicals but designed to break down faster. They have additives that speed up their rate of decay or breakdown in the presence of oxygen and light. The presence of moisture also accelerates the breakdown process. Mainly, they breakdown in presence of the sun’s UV light with some only breaking down at high industrial-scale temperatures. The most common examples include polybutyrate adipate terephthalate (PBAT), polybutylene succinate (PBS), polyvinyl alcohol (PVOH/PVA), and polycaprolactone (PCL).
Advantages of Using Biodegradable Plastics
1. Biodegradable plastics are easy to recycle
These types of plastics not only take less time to decompose when discarded but can also be easily recycled through an organic process. They are also non-toxic since they have no chemicals or toxins. Recycling helps to lessen landfill problems and besides, the recycled bio-waste can be used as compost or as renewable energy for biogas.
2. They consume less energy
Less energy is needed in the manufacturing of biodegradable plastics compared to ordinary plastics. For instance, the manufacture of corn-based polymer requires 65% less energy compared to a similar polymer made from petroleum. Manufacturing bioplastics also do not require the process of finding, accessing, and transportation of hydrocarbons.
This means fewer fuel fossils will be in use hence, reduction of environmental pollution. Also, it produces 68% fewer greenhouse gases during its manufacture, posing a significant environmental benefit.
3. Management of waste reduction
Biodegradable plastic breaks down only in a period of a few months, depending on the material used to make the bioplastic and the method of disposal. Other types of traditional plastic constitute 13 percent of the waste stream that is 32 million tons of trash annually, and only 9 percent of this type of plastic can be recycled.
Biodegradable plastics are a better choice as they are broken easily, and can be absorbed by the soil or converted into compost. Moreover, even if a complete breakdown does not occur, it is easy to achieve a reduction in the amount of space required to dispose of the globe’s plastic waste.
4. Lower petroleum consumption
Oil is a significant ingredient in the manufacturing of traditional plastics. Petroleum is known to have negative impacts on the environment, considering the amount of waste produced during refinement and also during the extraction of oil from the earth.
Biodegradable plastics use the idea of natural products; therefore, the use of bioplastic can profoundly reduce the amount of petroleum used and consequently lessen its environmental hazards.
Composting of bioplastic products can make the soil fertile, thereby enhancing soil fertility. The reason for this is because plastic is not made using artificial chemicals but from natural materials. The materials decay improves the soil’s water and nutrient retention and helps in the growth of healthier plants with no need for pesticides and chemical fertilizers.
6. Reduction of carbon dioxide levels
The production of plastics has increased significantly over the years. Scientists have approximated that by the year 2050, there could be more plastics in the ocean than fish. Drinking water will be contaminated with 80% of microplastic at that time.
With biodegradable plastics, such as those made from sugar and carbon dioxide by researchers from the University of Bath, the world foresees a future of plastics that can decompose and release only the amount of energy that was used to make it.
7. Reduction of emission of greenhouse gas levels
The use of biodegradable plastic products instead of traditional plastics lessens the amount of greenhouse gas emissions. Research from North Carolina State University states that plastic products harm the landfills as they produce an intoxicating greenhouse gas when burnt. Switching to bioplastics can profoundly reduce the number of greenhouse gasses emitted, consequently avoiding its effects such as desertification and extreme flooding.
8. Biodegradable plastics products do not release harmful products upon decomposing
Discarding traditional plastics can also mean releasing methane, toxic chemicals, and other types of pollutants to the environment. These substances are upon breaking down, are potentially dangerous as they can easily harm marine and terrestrial ecosystems, and human overall health as well.
Bisphenol A – a significant component in the manufacturing of plastics, for instance, is associated with endocrine disruption that is incredibly harmful to the reproduction cycle of human beings. Other artificial chemicals in traditional plastics have also been linked to diseases such as cancers.
Disadvantages of Biodegradable Plastics
1. Engineering problems
Biodegradable plastics are made from plants such as soybeans and corn. Therefore, there is a risk of contamination as the crops are typically sprayed with pesticides when on the farm and can easily be transferred or included in the end product.
2. Need for costly equipment for both processing and recycling
A downside of biodegradable plastic is that there is a need for costly industrial processors and composters, especially those that require high industrial-scale temperatures to be broken down. Apart from cost, there is a need for the availability of equipment which may be a problem.
3. Risk of contamination due to confusion differentiating between bio-degradable and non-biodegradable plastics
These bioplastics should not be mixed with non-biodegradable plastic when discarded. The challenge today is that many people do not know how to distinguish between the two. Therefore, these bioplastics may end up getting contaminated and may not be easily recyclable anymore. The outcome is adding up the waste volume.
4. Biodegradable plastics may produce methane in landfills
Some biodegradable plastics produce methane when decomposing in landfills. The amount of methane produced each year is high. Methane is 84 times more potent than carbon dioxide, and it absorbs heat faster; therefore, it can accelerate climate change.
5. Surprisingly, biodegradable plastics do not solve ocean pollution problems
These types of plastics cannot decompose in the ocean waters as it is too cold. Therefore, these plastics will either float on water or create micro-plastics which pose health hazards to marine life. The use of these kinds of plastic cannot solve all pollution problems.
6. There is a need for more crops and croplands to produce biodegradable plastics
Adequate production of these kinds of plastic will require the use of cropland to provide the natural materials required instead of producing food. With food scarcity and hunger affecting 1 out of 5 families in the developed nations and much more in developing countries, there is an ethical question whether it is right to expand this industry.
7. Biodegradable products come at a higher cost
It costs 50% more to produce bioplastic than to produce traditional plastic. With improved technologies and more access to materials, however, this cost can reduce significantly.
8. Biodegradable plastics may contain metals
Some of these plastic products, for example, plastic bags, may release some amount of heavy metals during decomposition. In 2009, for example, the Guardian reported high levels of cobalt and lead in one brad of this kind of plastic. It raised issues about the toxicity left after decomposition.
Uses of Biodegradable Plastics
Biodegradable plastics are used in many areas of our daily lives today. Some of these uses are;
- They make Shopping bags, compostable waste collection bags, and trays, punnets for fruits, meat, and vegetable.
- Medical department uses bioplastics to make screws, pins, and plates, materials for pills and capsules.
- They are used to make disposable catering service wares.
- They also make items such as bottles, tea bags, jars, air pillow, pens, pencils sharpeners, mulch film.
Ren, X. (2003). Biodegradable plastics: a solution or a challenge?. Journal of cleaner Production, 11(1), 27-40.
Chiellini, E., & Solaro, R. (Eds.). (2012). Biodegradable polymers and plastics. Springer Science & Business Media.
Ebnesajjad, S. (Ed.). (2012). Handbook of biopolymers and biodegradable plastics: properties, processing and applications. William Andrew.
Koushal, V., Sharma, R., Sharma, M., Sharma, R., & Sharma, V. (2014). Plastics: issues challenges and remediation. International Journal of Waste Resources, 4(1), 2-6.
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