Bioplastics: Designing Sustainable Alternatives to ABS plastics

We made Bioplastics as a replacement for conventional ABS plastic to replace harmful properties such as non biodegradability then tested and compared different factors such as strength.
Baraki Abobaker, Hamzah Alia
Al-Amal Academy
Grade 8

Hypothesis

If a safe, cheap, kitchen based bio plastic is developed, then it can provide a renewable and biodegradable alternative to conventional ABS plastic, potentially replacing petroleum based materials in everyday applications, therefore lessening plastic pollution. 

Research

Background Research What are Bio Plastics? BioPlastics are materials made from renewable sources such as starch, milk proteins, or seaweed instead of petroleum. Unlike plastics such as ABS, derived from fossil fuels and often persist for centuries, bioplastics are biodegradable and can break down naturally in soil. They can be designed to mimic the strength, flexibility, and durability of conventional plastics, making them promising for packaging, agriculture, and consumer goods.  Types of Bio Plastics

  • Protein- Based (Casein): made from milk proteins, can form hard, moldable plastics
  • Polysaccharide-Based (Starch, Agar) – renewable, biodegradable, and flexible when mixed with glycerol.
  • Synthetic Biodegradeable (PVA blends) -  based on polyvinyl alcohol (found in school glue), biodegradable under certain conditions and stronger than starch-only plastics.

Why do we need Bio Plastics?

  1. Plastic Pollution: Conventional plastics like ABS do not biodegrade, creating long term waste in oceans and landfills.
  2. Fossil Fuel use: ABS and similar plastics are petrol based, linking them to climate change. Eco-Friendly Alternative: Bioplastics can be produced from renewable or waste sources (like spoiled milk or cornstarch). 
  3. Real World Impact: If Bioplastics can replicate the useful properties of ABS, they could replace it in certain applications like packaging or disposable items,  greatly reducing environmental harm. 

What is ABS? ABS stands for Acrylonitrile-Butadiene-Styrene. It’s a petrol based thermoplastic, meaning it softens when heated and hardens when cooled. It can be molded into many shapes. ABS is strong and durable, lightweight but rigid, heat resistant, easily molded, delicate and good looking. However, the main reason this has been brought up is not for its benefits, but also because ABS is not biodegradable, meaning it stays in the environment for hundreds of years, affecting our wildlife and us too. 

Environmental Impact of ABS Plastic

Non-Biodegradability

Acrylonitrile Butadiene Styrene (ABS) is a non-biodegradable plastic that can persist in the environment for hundreds of years. Because it resists microbial breakdown, ABS accumulates in landfills and natural ecosystems, contributing to long-term pollution. Over time, it can fragment into microplastics that contaminate soil and waterways, posing risks to wildlife and potentially entering the human food chain. Petroleum-Based Composition

ABS is made from three monomers—acrylonitrile, butadiene, and styrene—all derived from petroleum. These are non-renewable resources whose extraction and processing releasesignificant greenhouse gases. The European Chemicals Agency classifies some of these monomers as toxic and potentially carcinogenic, making the production process harmful to both the environment and human health. Pollution from Production and Disposal During production, ABS manufacturing emits volatile organic compounds (VOCs) and styrene fumes, both of which are regulated air pollutants. When burned or incinerated, ABS releases hazardous substances such as carbon monoxide and hydrogen cyanide. These emissions contribute to air pollution, climate change, and health hazards, especially in areas without proper waste management systems. Challenges in Recycling

Although ABS is technically recyclable, practical recycling rates are very low. Its frequent use in mixed-material products, such as electronics and toys, makes separation and reprocessing difficult and economically inefficient. As a result, most ABS waste ends up in landfills or is incinerated, perpetuating the cycle of pollution and resource depletion. Microplastic Pollution As ABS products degrade physically under sunlight or mechanical stress, they form microplastic particles that persist in marine and terrestrial environments. Studies have detected ABS fragments in marine sediments, demonstrating its role in microplastic pollution. These particles can harm aquatic organisms, accumulate in the food web, and transport toxic chemicals across ecosystems. Overall, ABS poses significant environmental challenges due to its persistence, fossil fuel dependency, emissions, and contribution to plastic pollution.

(Note that other things such as bioplastic recipes were also researched, they were just put into a different section)

Variables

  • Independent Variable: Type of bioplastic used
  • Dependent Variable: Strength (maximum weight supported)
  • Controlled Variables: Drying time, ingredient amounts, temperature, testing method

Procedure

We gathered the following materials and then began our procedure:

  • Whole Milk (500 ML)
  • White Vinegar (50 ML)
  • Agar powder (40 g)
  • Cornstarch (40 g)
  • School glue (PVA) (100 ML)
  • Glycerol (vegetable glycerin, 50 ml)
  • Heat resistant beaker or measuring cup
  • Digital kitchen scale
  • Thermometer
  • Soil container

Step 1: Prepare the bioplastics

  • Agar plastic: Mix 20 g agar, 10 g glycerol, 250 mL boiling water, pour into mold, dry 48 hours.
  • Starch plastic: Mix 20 g cornstarch, 10 g glycerol, 250 mL boiling water, pour into mold, dry 48 hours. 
  • PVA plastic: Mix 50 mL school glue, 10 g cornstarch, 10 g glycerol, stir, pour into mold, dry 48 hours. 

Step 2: Test strength

  • Tensile strength: Clamp each end of a strip and add weight until it breaks. Record maximum mass supported.

Step 3: Record observations     Record observations and weight support over several tests and note down

Observations

Agar plastic: Day 1-3: The agar plastic started out as a liquid, but after cooling for about an hour, it developed a jello-like texture and couldn’t yet be split into samples. After 3 hours, it became more rubbery and plastic-like, though still fragile and not fully hardened. By the next day, the agar plastic felt malleable and somewhat thick, with uneven sides ranging from 1–2 mm to 3–4 mm. Day 4-7: The agar plastic continued drying and became much harder, shrinking to nearly half its original size. Each day, it was flipped to ensure even drying, and with every observation, it had shrunk slightly more. Its surface became firmer and smoother, showing clear signs of solidification and moisture loss over time. Day 7-10: Over the final 3 days, the agar plastic was shrinking every new day. It was hardened a lot mostly on the edges, however the middle was still a bit soft and not fully hardened.  This was the most it would likely harden, unless frozen. 

Cornstarch plastic:  Day 1–3: The cornstarch plastic began to harden around the edges, which was a good sign of progress. However, the centre stayed soft, sticky, and fragile — when touched, it tore apart easily. Although the middle wasn’t fully set, the firm edges suggested it was drying and developing as expected. Day 3-6: The cornstarch plastic continued to shrink noticeably and developed visible wrinkles as it dried. By this stage, most of the sample had hardened, although the centre remained slightly soft compared to the edges. The outer edges were very firm, plastic-like, and difficult to bend, which indicated that the cornstarch plastic was curing and strengthening as expected. Day 7-10:  The cornstarch plastic had fully hardened, with edges that were extremely firm and difficult to tear. Although it did not form a full, uniform sheet like some of the other samples, it still demonstrated strong durability. Its rigidity and toughness suggest that it could realistically be used for everyday items such as disposable cups, plates, or other lightweight plastic products.

PVA plastic: Day 1–3: The PVA plastic hardened the most out of all the samples, developing a smooth, leather-like texture. It appeared to be the strongest and most durable so far, making it seem like the most successful plastic. However, it was slightly smaller than expected and remained a bit too flexible, suggesting it might need more time to fully cure. Day 3-6: The PVA plastic hardened well and developed a very smooth surface. Although it turned out thinner than expected, this could be improved in future trials by increasing the amount of material used. The sample was flexible and easy to bend, yet unlike the other plastics, it hardened evenly across its entire surface. This uniform consistency indicates a stable and reliable curing process. Day 7-10:  The PVA plastic didn't change much, with the only noticeable change being hardening. It remained the same size and didn't shrink at all during the whole testing phase, unlike every other plastic tested. 

Analysis

Each Bioplastic had different strengths and weaknesses. Cornstarch was the hardest, good for toys, but brittle and easy to break. PVA the most balanced as it was flexible and strong. Agar plastic was the strongest and most flexible, but it wasn't hard enough.

Another analysis is that if our project was used in an industrial lab with funding and strong materials, it would be much stronger.

Conclusion

This experiment showed that bioplastics are a viable option to replace petroleum based plastics in the future. The agar plastic was the best recipe, excelling in not only functionality but also strength. The cornstarch plastic was the hardest, however was weak and could not hold much weight. The PVA plastic was both hard and flexible, however not very strong. Every plastic could be used in different situations and every plastic was strong in a different way. 

Application

Real-World Application

Bioplastics like agar, PVA, and cornstarch-based plastics can be used as sustainable alternatives to traditional petroleum plastics in packaging, agriculture, and everyday products. To apply bioplastics to the real world, this idea would need to be given and advanced by a company with greater funding, industrial level lab equipment, and experienced scientists. Of course, we tried our best with what we could do, however it could not be comparable to what a company could do with this idea. Because bioplastics are made from natural and renewable materials, they break down much faster than petroleum plastics, which can take hundreds of years to decompose. This helps reduce long-term pollution in oceans, landfills, and ecosystems. They also produce fewer toxic chemicals when they degrade, lowering the risk of harming wildlife or contaminating soil and water. Compared to ABS plastic, which is made from fossil fuels and releases microplastics and harmful chemicals as it breaks down, bioplastics are significantly more environmentally friendly. ABS is strong and durable, but it is not biodegradable, contributes heavily to plastic pollution, and has a high carbon footprint during manufacturing. Bioplastics offer a cleaner, safer optiont hat reduces waste, conserves resources, and supports a more sustainable future.

Sources Of Error

Some sources of error we encountered were:

  • We didn't have the material to make a bigger sample batch
  • We didn't have enough material to perform more tests
  • Some plastics didn't harden or smooth out as expected

Citations

Acknowledgement

We would like to acknowledge our science teacher, Mrs. Louise Sarvari for guiding and giving us advice, and we would like to acknowledge our parents for their support and help with purchasing materials.

Some research was advanced through the use of Artificial Intelligence, and the idea was found online.