In this project, the goal was to make PLA (a biodegradable material), actually biodegradable in the use case scenario.

There are various differences between computers and the real world. One of them is, that at the end of life of a product, you can delete it. The same does not happen out in the real world.

A large number of consumer products are made of different kinds of petroleum derived plastics. These products, apart from being non – biodegradable, require a lot energy during production, and have high emissions.

With growing awareness of sustainability issues, research has led to companies with biodegradable material offerings. These materials, based on market fit, are being introduced in various products in the market, especially packaging. However, a major issue with a few promising products is that, even they claim (and are) biodegradable, in reality, they require special conditions to biodegrade. In essence, left on their own in landfill and nature, they too will take decades before actually biodegrading.

As things stand today, there is a lot of time before have a completely circular economy, even as countries take measures towards sustainable economy.

Literature Research

As a first step, I looked into an upcoming material PLA. I studied the production, polymerization, mechanical properties, properties under various conditions, manufacturability, and finally bio-degradation. I also studied the material under the circular economy framework to look at carbon footprint, and the implications of using various materials/systems as composting facilities. I conducted research on the Indian recycling scenario, met with local vendors to understand the financial flow of the recycling system in the country that consists of a large number of level and steps.

Experimental work

I soon realized that the current form of PLA being introduced was more economically driven than ecologically. I decided to design a product out of PLA that would be biodegradable. As a designer, I always start from thinking about user behaviour and habits first, and so this was no different. 

Among the design drivers, were the following frames of reference of the problem:

1. A majority of the discarded product will end up in landfills. Why? How can this be prevented?

2. These materials do not bio-degrade automatically in nature. However, given special composting conditions, this is possible. How can the product itself act as its own composting facility, if it ends up in a landfill?Does the entire process have to be bio-degradation or is the sustainable goal something else?

3. People have a tendency to throw things anywhere they like (atleast in India). Is there a cultural insight to this behaviour that can be leveraged in order to drive the product?

With this in mind, I started conducting experimenting on PLA with various chemicals and mechanisms to study the rates of bio-degradation. 

The Switch

I realised that the answer to point 3 could be potentially useful; In India, people have a tendency to crush things before they throw them (e.g. bottles, cups) in order to (at least psychologically) ensure that those articles are not re-used. I theorised that the crushing could be a switch for the biodegradation to start. Biodegradable materials start degrading the moment they are formed, and hence have a low shelf life. Materials like plastics on the other hand don't biodegrade, but have a good shelf life. What was required, then, was something in between. Something that had a good shelf life till the time you wanted it, and then started to bio-degrade after that. Having used a PLA ribbon for my initial experiments on making PLA biodegradable, I decided to use off the shelf PLA articles.

The process was simple. Upon crushing the cup, a brittle layer on the outside of the cup would break, exposing the inner coating to the moisture in the air. This coating needed to start reacting with PLA in presence of moisture, but not without it. Solid-Solid reactions are much slower than solid liquid reactions. So that was one clue. Hydrolysis of PLA requires water, and heat. Only water biodegrades PLA much slower because of steric hindrance caused by the size of molecules involved. Generally, microorganisms solve that problem with enzymes. Therefore, I needed a coating that could hydrolize PLA effectively. I tested various chemical compositions (mostly food safe ones) and after 22 samples, I finally found something that worked!

The optical microscopy results below confirm the accentuated rate of degradation in the formulation after exposure to moist air.

Optical Microscopy results : Left to Right (Untreated, Treated (before crushing), Treated (after crushing) [PLA cups disposed in open environments, observed after a period of 10 days]

The results of the test are being compiled for a patent application; A private bottling company in Mumbai has shown interest in the process and is currently in talks to fund further studies on the process.