PLA (Polylactic acid)
PLA is a bio-based and biodegradable polymer. As per the standards, it is called as compostable polymer. It looks similar to conventional polymers. The mechanical strength and other properties are comparable with the PP, PE, PET, PS, etc.
PLA is the most viable commercial biopolymer so far in terms of practical applications and large scale commercial production.
Insoluble in water; moisture and grease resistant.
The melting point is around 180°C and the glass transition is around 65°C.
The chemical formula is (C3H4O2)n
It is thermoplastic polyester and semi-crystalline with 37% of crystallinity.
It is manufactured from renewable resources like corn, sugarcane, tapioca, sugar beets, wheat, etc; agriculture and food waste can also be used. In short, it requires plant sugar from any of these feedstocks.
The plant sugar is converted into Lactic acid by fermentation. This lactic acid needs to be purified in several steps. The pure lactic acid is converted into crude lactide by pre-polymerization and depolymerization sequentially. The crude lactide needs to be purified by crystallization and distillation. The purified lactide is the monomer and it is polymerized into polylactic acid (PLA) by ring-opening polymerization.
Currently, two commercial plants are manufacturing PLA. The first and biggest player is Natureworks in Nebraska, the USA started in 2011. The second one is Total-Corbion in Rayong, Thailand started in 2019.
Natureworks uses Corn as raw material, whereas Total-Corbion uses Sugarcane to manufacture PLA.
Currently, technologies are available from European companies to establish manufacturing facilities anywhere in the world. As it is patented intellectual properties, the cost of the technology is high.
There are various standards to certify the product as a compostable.
PLA complies with all these standards to be called compostable.
PLA gets converted into CO2, water and compost by degradation. It is the same CO2 and water, which was consumed during the plant growth (for e.g. corn plant consumes CO2 and water and gets converted into corn; the corn used to manufacture PLA and degradation of PLA leaves CO2 and water).
Hence, it creates a circular economy without leaving any adverse footprint on the Earth, unlike petrochemical-based polymer.
The degradation rate and environmental condition to biodegrade for PLA is comparable with wood degradation.
Source of image: Total-Corbion
It can be used in almost all the single-use plastic applications like blown film, extrusion, thermoforming, injection molding products, etc.
It has secured an important place in 3D printing.
Textiles & Technical textiles products like non-woven products, garments & apparel, fibers, medical plastic and medical textiles.
It has started being used in automobile parts and other technical & engineering applications.
Various grades of PLA are developed to use in different applications.
In today’s market:
Mcdonald is using coffee cup lid and other products made from PLA.
Toy companies like Lego, Mattel, Hema, Lol, Mcdonald toys, etc. have started manufacturing toys from bioplastics, where PLA is one of the major components with bio-additives. Moreover, many companies have launched compostable clothes for children.
There are dangerous chemicals available in petrochemical-based plastics such as bisphenol A (BPA), phthalates and heavy metals such as lead and cadmium. These chemicals have an adverse effect on human health, especially for children. It affects the hormonal system and called endocrine disruptors. US and EU have already banned these chemicals’ use in toys.
A large number of companies are producing food packaging and foodservice ware products from PLA all over the world. For example, there are more than 30 companies manufacturing PLA products in India only.
US and EU have started using compostable non-woven fabric to manufacture different medical and hygiene products, where PLA contributes a major part.
Almost all of the airlines have replaced plastics with bioplastics, where a major contribution is from PLA. Most of the airports too.
All the tea bags and coffee capsules are almost replaced by compostable plastic.
Scenario in India
As per an estimate from exhibitors & speakers of Bioplastex 2019 (Bangalore),
India imports more than 30,000 Tonnes of PLA per year and bioplastic consumption in India is growing rapidly at a CAGR of over 23%.
As it is imported from US and EU companies, the price of the material is high, though the market is expanding rapidly. If it would be started being manufactured in India, the price can come down by almost 25-30%. Actually, India needs this kind of solution to get rid of the single-use plastic pollution problem and this could be one of the significant solutions.
The main drivers of the bioplastic industry in India are government rules & regulations, public awareness, Technology development and cost reduction. Out of these, it is largely dependent on central as well as state government’s policy on single-use plastic.
If the Indian government acts like Thailand one, India carries the potential to emerge as a global leader for bioplastics raw material and finished products. This will not only benefit the environment, ecology and plastic processing industry but also benefit the farmers by selling their agricultural products at a competitive price to bio-based industries.
This motivation will escalate nationwide farming and help to boost the economy significantly. Indian agriculture sector provides employment to 50% of the total workforce and contributes 18% of India’s GDP. As rightly said, if the farmers are economically strong, the whole country’s economy will be stronger. In addition, India has much larger agricultural land then it’s current production, contract farming could be a noteworthy option.
To conclude, bio-economy and bio-based industries have the capability to contribute towards a sustainable future exceptionally and revitalize the economy.