What Is a Biomass Plastic?
A biomass plastic is a polymer material chemically or biologically synthesized from renewable biomass resources.
Although not necessarily biodegradable, they are known as environmentally friendly plastics due to their carbon neutrality. Since there are various raw materials, chemical structures, manufacturing methods, and functions, it is important to understand the characteristics of each material before using the appropriate one.
Uses of Biomass Plastics
Biomass plastics are used in a variety of fields as environmental measures are strengthened.
Specific uses of are as follows:
- Non-food containers and packaging
- Clothing fiber
- Electrical and Information Equipment
- OA equipment
- Automobiles
- Eco-friendly educational equipment
- Cushions
- Artificial grass (lawn)
- Heat-resistant tableware containers
Principle of Biomass Plastics
Biomass plastic is a polymeric material chemically or biologically synthesized from renewable biomass resources. In other words, the raw material of biomass plastic is plant material that grows through photosynthesis using carbon dioxide.
Therefore, even if biomass plastics are incinerated and emit carbon dioxide, the total amount of carbon dioxide absorbed during growth and the total amount of carbon dioxide emitted during incineration is plus or minus zero, making them highly carbon neutral. Biomass plastics can be biodegradable or non-biodegradable.
Attempts are underway to make them biodegradable and return them to the soil to achieve a cycle in which plants are grown as raw materials. Thus, plant-derived raw materials for biomass plastics can be cultivated, and there is no concern about depletion compared to petroleum-derived raw materials.
Types of Biomass Plastics
There are three main types of biomass plastics. The most common of these are made from biomass resources, including inedible parts such as sugar cane and corn.
1. Biodegradable Biomass Plastic
Biodegradable biomass plastics are plastics made from biomass resources and are biodegradable. Typical examples are polylactic acid and polyhydroxyalkanoate (PHA). Of the many biodegradable plastics, polylactic acid (PLA) is the most commercialized. However, its limited popularity is due to its difficulty in molding, high price, and low strength.
2. Non-Biodegradable Biomass Plastics
Non-biodegradable biomass plastics are plastics whose raw materials are biomass resources but are not biodegradable. Typical examples are biopolyethylene and biopolyamide. They are not biodegradable, but they can achieve carbon neutrality. Although they are easier to handle than biodegradable plastics, their use is limited due to their higher price compared to general-purpose plastics.
3. Partially Biomass-Based Plastics
Partially biomass feedstock plastics are plastics produced using biomass feedstock as part of the raw material. Examples include polypropylene terephthalate (PPT), which is made by fermenting propylene glycol, one of the raw materials. Copolymers of polylactic acid and cellulose acetate also belong to this category.
Other Information on Biomass Plastics
1. Relationship With Biodegradable Plastics and Bioplastics
The difference between biomass plastics and biodegradable plastics is that biomass plastics are defined by their raw materials, while biodegradable plastics are defined by their function.
Biomass plastics, as we have mentioned, are polymeric materials chemically or biologically synthesized from renewable biomass resources as raw materials. Some biomass raw materials are biodegradable and some are not.
Biodegradable plastics, on the other hand, are plastics that are degraded by the action of microorganisms in the environment, and the raw materials are not necessarily of biological origin. For example, polybutylene adipate terephthalate (PBAT) is made from petroleum, which is derived from fossil resources, and sugarcane, which is derived from biomass.
Note that biodegradable plastics are used in plastic shopping bags, product packaging, drainage nets, computer parts, sandbags, fishing line, and agricultural mulch sheets. These are collectively called “bioplastics.”
2. Environment Surrounding Biomass Plastics
Global efforts to address environmental issues, particularly global warming, began with the Kyoto Protocol enacted in 1997. Global warming is believed to be caused by carbon dioxide and other greenhouse gases, and an international framework was established to curb their emissions. The Kyoto Protocol was limited to developed countries, but the Paris Agreement of 2013 includes developing countries.
Against this backdrop, many countries are working to reduce their carbon dioxide emissions, and one such effort is the conversion to biomass plastic. However, biomass plastics may cause the same problems as general-purpose plastics when they are disposed of, since few biomass plastics are made of 100% biomass materials. Besides, technological innovations as well as legislation are needed.
3. Problems With Biomass Plastics
Like regular plastics, biomass plastics have a microplastic problem. Many of the biomass plastics in use today are only partially biodegradable, and the remaining plastic fragments are crushed by the external environment, but they are not decomposed.
The remaining plastic fragments are crushed by the external environment, but they do not decompose. The final result is microplastics ranging in size from several micrometers to several tens of micrometers, which accumulate in animal bodies and are thought to have adverse effects on ecosystems and the human body through the food chain process.