What Are Bioplastics & How Are They Being Used?

Plastic pollution has become a global environmental issue and there is a growing need for sustainable alternatives to traditional plastics. Bioplastics are one such alternative that has gained popularity in recent years. They are made from renewable sources and have the potential to reduce the environmental impact of plastic production and disposal.

To explain further, Ansini, specialists in vacuum forming and thermoplastic moulding, share their insight into what bioplastics are, and how they are being used.

Types of bioplastics 

There are three main categories of bioplastics, each with its own unique properties and characteristics. These are biodegradable, compostable, and bio-based plastics. Here is a brief guide to each type. 

Biodegradable plastics 

Biodegradable plastics are produced from renewable sources such as corn starch, sugarcane, and potato starch. They are specifically designed to decompose naturally in the environment over time, mainly through a process called aerobic degradation. 

The plastics gradually break down into smaller fragments when exposed to moisture, oxygen, and microorganisms in the environment, eventually disintegrating into water, carbon dioxide and biomass. The length of time required for biodegradable plastics to decompose can, however, vary significantly depending on the type of material and the environmental factors.  

Although biodegradable plastics can be beneficial in reducing plastic pollution in the environment, they may not be suitable for certain applications since some require specific conditions for proper degradation. 

Compostable plastics 

Compostable plastics, unlike biodegradable plastics, are intended to break down faster and more thoroughly in composting environments. These plastics are typically composed of materials like vegetable matter, cellulose, and starches. Compostable plastics can be decomposed into nutrient-rich soil that can be utilised in agriculture, forming a closed-loop solution. 

That said, compostable plastics demand specific composting conditions like an appropriate level of temperature, humidity and oxygen and may not be appropriate for all composting systems. To ensure their complete and safe breakdown in a composting facility, compostable plastics must meet certain standards, such as the ASTM D6400 or EN 13432 certifications. 

Bio-based plastics 

Bio-based plastics are produced from renewable resources like plant-based materials or agricultural waste, and they can be either biodegradable or non-biodegradable. These plastics can aid in reducing reliance on fossil fuels and lowering the greenhouse gas emissions linked to conventional plastic production. 

Despite this, some bio-based plastics may not be as environmentally friendly as they seem. This is due to the significant resources required for their production and the direct competition with food crops for them. Additionally, bio-based plastics can be more expensive to manufacture than traditional plastics. 

How bioplastics are made 

The manufacturing process of bioplastics depends on the specific type of bioplastic being produced. Typically, bioplastics are made from renewable resources, such as corn, sugarcane, potatoes, or other crops. The first step in the production process is to process the raw materials to extract the desired components, such as starch, cellulose, or oils. 

The extracted components are then processed into monomers, which are the building blocks of polymers. Polymers are long chains of molecules that are used to create plastics. The process of creating polymers from monomers is called polymerization. 

There are different methods of polymerization used for different types of bioplastics. For example, polylactic acid (PLA) is a bioplastic that is produced by polymerizing lactic acid, which is derived from cornstarch. In contrast, polyhydroxyalkanoates (PHA) bioplastics are produced by bacteria that consume sugar and convert it into polymer chains. 

In addition to the raw materials and production methods used, bioplastics can also contain various additives to enhance their properties. For example, plasticizers can be added to make the plastic more flexible, while fillers can be used to increase strength. Colourants can also be added to give the plastic a specific colour. 

Producing bioplastics vs producing traditional plastics 

The production process of bioplastics differs from that of traditional plastics in two key ways. 

Firstly, traditional plastics are typically manufactured using petrochemicals, which are sourced from non-renewable resources like crude oil or natural gas. Conversely, bioplastics are made from renewable resources like corn, sugarcane, or other plant-based materials. This makes bioplastics a potentially more sustainable option that could help reduce reliance on fossil fuels and lessen the environmental impact of plastic production. 

Secondly, the production of traditional plastics typically involves multiple stages, such as extracting petrochemicals, refining them and then polymerizing them into plastic. This process requires a considerable amount of energy and results in significant greenhouse gas emissions. In contrast, the production process of bioplastics is often viewed as more energy-efficient and eco-friendly. 

The production of bioplastics does, however, also create some challenges. For example, the cultivation of crops used to produce raw materials for bioplastics can require large amounts of land, water, and energy. Additionally, the production of some bioplastics can still produce greenhouse gas emissions, such as in the process of producing bioplastic from sugarcane, which can contribute to deforestation and land-use changes. 

In terms of recycling, traditional plastics and bioplastics have different properties. Many traditional plastics can be recycled several times, whereas some bioplastics may not be recyclable at all. Additionally, the recycling of bioplastics can require special processing and may need to be separated from traditional plastics to avoid contamination. 

How bioplastics are used 

Bioplastics have a wide range of potential applications, with many industries and products starting to adopt them. One of the most common applications of bioplastics is in packaging. Bioplastics can be used to make bags, containers and wrapping films that can be composted or recycled after use, providing a sustainable alternative to traditional plastics. In addition to packaging, bioplastics are also being used in the textile industry to make sustainable clothing and accessories.

Some bioplastics can also be used in electronics, such as smartphone cases and computer parts. 

Using bioplastics in packaging and other products has several advantages, one of which is its potential to reduce the environmental impact of traditional plastics. Since bioplastics are derived from renewable resources and can be biodegradable or compostable, they do not accumulate in the environment and can break down naturally. Furthermore, the production of bioplastics can generate lower greenhouse gas emissions than traditional plastics, making them a more sustainable choice. 

There are, however, also some disadvantages to using bioplastics in certain applications. For example, some bioplastics may require specific composting conditions to break down, which may not be available in all locations. Additionally, the production of bioplastics can be more expensive than traditional plastics due to the use of more expensive raw materials and the need for specialised production equipment. Finally, bioplastics may not have the same durability and strength as traditional plastics, which may limit their use in certain applications.