Single-use plastics have become the biggest environmental menace for both consumers and companies alike. People are fed up of plastic trash piling up and harming the nature. However, we had to tolerate plastic packaging since there were no ideal alternatives to it.
Fortunately, things are changing for the better with biodegradable packaging entering the markets in a big way. Biodegradable plastics or Bioplastics have emerged as a viable alternative for packing foods and other perishables, relieving FMCG companies that were struggling to reach their sustainability goals. Today, there are various options for biodegradable packaging available in the market, but not all of them biodegrade easily without any effort. In this article, let’s look at each of these options and compare their Biodegradability factor so that you can make the right decision!
Biodegradable plastics or Bioplastics
Bioplastics are an eco-friendly alternative to conventional plastic polymers that could be an excellent replacement since their manufacturing results in fewer emissions of greenhouse gases and they are biodegradable. They are made from biodegradable thermoplastic polymers such as Polylactic acid, Polyhydroxyl alkanoate, Polybutylene succinate, etc., which have similar properties like regular petrochemical plastics.
Bioplastic materials can be derived from various raw materials such as vegetable fats, corn starch, pea starch or microbes. The first notable usage happened way back in 1910, when Henry Ford designed automotive parts for the Ford Model T car from corn starch and soybean oil ingredients. Since there are too many types of bioplastic materials in the market today, we have considered only the top three types that have a significant market share in this article:
Various types of Biodegradable Plastics
Poly-lactic acid (PLA)
PLA is the most widely used bioplastic material today, constituting about 60% of the global bioplastics market. It is a transparent solid polymer that is similar to PET polymers but has a significantly lower maximum continuous-use temperature. Corn starch is the main raw material for PLA, which is bio-based and fully biodegradable.
However, biodegradable bags and bottles made out of PLA cannot be thrown away in landfills nor can they be composted at home to be biodegraded naturally. They need certain conditions with proper temperature and need to be properly managed in specialized industrial composting or recycling facilities. Under the right circumstances, microbes can turn the material into carbon dioxide and water within a couple of weeks.
Poly hydroxyl alkanoate (PHA)
PHA is an eco-friendly polymer that can handle high temperatures, with properties similar to polypropylene. Its raw material is bacteria culture so it is completely bio-based and compostable at home. PHA is a thermoplastic biodegradable polymer with a melting point of ~180 °C and thermal and mechanical properties similar to those of isotactic polypropylene (PP).
Among biodegradable plastics, polyhydroxyalkanoates (PHAs) are particularly noteworthy because of their excellent marine biodegradability. PHA is biodegraded by various marine microbes in a wide range of marine environments, which can happen within a few weeks. However, its production process is quite costly, which is a major constraint for the wider commercialization of PHAs. A major reason for their high cost is the price of the carbon substrate used in the microbial cultivation process, which can account for 45-50% of the total production cost.
Polybutylene Adipate Terephthalate (PBAT)
PBAT exhibits the best mechanical properties similar to plastics and is biodegradable as well. Its physical properties are often compared to low-density polyethylene, a stretchy polymer used to make films such as for trash bags. PBAT combines some of the beneficial attributes of both synthetic polymers and biobased polymers. It is produced from common petrochemicals—purified terephthalic acid, butanediol, and adipic acid—and yet it is biodegradable.
PBAT is regularly blended with PLA, a polymer with rigid, polystyrene-like properties that lend stiffness. As a synthetic polymer, it can readily be produced at large scale, and it has the physical properties needed to make flexible films that rival those from conventional plastics. PBAT is often used as mulching films and compostable refuse bags, which biodegrade in nature within nine months.
Paper Coated With Bioplastics
Paper has always been considered an eco-friendly alternative to plastic packaging material. However, its biggest drawback was its water absorption; meaning it will readily become wet and soggy. So we could only pack and carry dry items in paper bags. Food packaging is typically laminated with a thin layer of plastic in order to make it grease-resistant.
Fortunately, new developments have allowed paper packaging material to be coated with Bioplastics such as PLA or PBAT, which makes them waterproof, and yet recyclable and biodegradable. Researchers across the globe are developing alternative coatings for paper using polybutylene succinate (PBS), by adding a small amount of cellulose nanocrystals to create a coating material. The added cellulose nanocrystals are the same material as the main component of paper, and this allows the biodegradable plastic to firmly attach to the paper surface during the coating process.
Certifications for Biodegradability
When bioplastics that are marked as ‘biodegradable’ reach the end of their lifecycles, they cannot be dumped in landfills. This is dangerous since they do not biodegrade that easily. Please note bioplastics biodegrade in a few months only in certain environments, and they are industrially compostable and recyclable.
Most are certified as ‘commercial compostable’ to be done in an industrial facility. This means most bioplastics are not compostable at home and will not biodegrade naturally in landfills or anywhere in open nature. Municipal waste collectors need to collect them and dispose separately in specific industrial facilities only. Bioplastic producers need to apply for proper certification for their products. They need to be tested for commercial compostability as per AS 4736, EN, ASTM and IS/ISO norms.
- Australian Standard AS 4736-2006: Standards for biodegradable plastic-biodegradable plastics suitable for composting and other microbial treatment in Australia
- European Norm EN 13432: This European Norm for compostability of packaging certifies that the plastic and all other components of the product are commercially compostable (colours, labels, glues and residues of the content).
- European Norm EN 14995: European Standard for compostability of plastics linked to the European Directive on Packaging and Packaging Waste 94/62/EC. Please note that EN 13432 applies when the plastic is used for packaging purposes.
- ASTM D 6400 or 6868: This American Society for Testing and Materials standard specifies the labeling of plastics and products made from plastics to be aerobically composted in municipal or industrial facilities.