Johnny Cai, Wendy Ma, Alex Jung, Sabiha Sultana and Hannah Tesch
- Community Partner: Aruna Revolution Health
- Degree: Bachelor of Applied Science
- Campus: Vancouver
Ninety percent of a disposable diaper consists of plastic, and each year, more than 30 billion disposable diapers end up in North American landfills.
We were asked to design a 100% compostable diaper with all the convenience and benefits of a disposable diaper. Our design needed to be soft and comfortable on the baby’s skin, absorb 6.8 times its weight in water, meet industrial composting standards and be affordable.
Rashmi Prakash, the co-founder of Aruna Revolution, was an amazing mentor. She inspired us with her vision of what’s possible, as well as her experience working with materials and transforming them into sustainable products.
Our design process and challenges
We began by researching the function of each layer of the diaper – the soft top layer that’s in contact with skin, the liquid distribution layer, the absorbent core and the leakage-proof bottom layer. Each layer has different material properties. In a conventional disposable diaper, these layers are made of plastic-based polymers. We needed to find compostable substitutes for each layer, as well as processes to make them and assemble the diaper.
We also wanted to find materials that were from sustainable sources. From the very beginning, our client emphasized the importance of this.
For example, cotton might be seen as a viable alternative, but there are a lot of negative environmental impacts associated with growing and bleaching cotton. This led us to consider materials that are traditionally viewed as waste. We were ultimately able to use waste materials for two of the four layers.
Putting together our prototype was a very manual and time-intensive process. We used a 3D-printed mold to create a sample that’s square in shape and about one-fifth the size of an actual diaper. We used compostable glue to put the layers together.
Our final result exceeded the liquid holding capacity of our requirement and our research validated that all materials could be composted within 90 days.
What excited us most
None of us have a background in materials research, so there were lots of opportunities to push ourselves in new directions. We had to be creative and look to different sources of materials.
The actual process of extracting fibre from materials and transforming it into a non-woven sheet was very exciting. There was definitely a lot of trial and error, but we were very persistent, and were ultimately able to come up with a process that worked. We also used some statistical software that helped us optimize our blend for performance and cost.
Finally, it was meaningful to work on a project to try and create a truly compostable diaper. Disposable diapers are a significant problem, and although some diapers are marketed as biodegradable, there’s a fair bit of greenwashing going on as these diapers do not biodegrade in landfills.
Our project’s future
The client was pleased with the results of our project, stating that it surpassed her expectations given the time frame and that our solution looks promising. We will be sending our product to our client for industrial tests and further development.