Plastic LCA Comparison for Sustainability Research

ISEF Category: Chemistry

Subcategory: Other  ·  Difficulty: Advanced  ·  Setup: University Lab  ·  Time: Full Year

The Hook

A plastic that breaks down faster is not always the greener choice. The full story includes raw materials, energy use, transport, and disposal. Life-cycle assessment, or LCA, helps you compare those hidden costs. That makes this project about more than a cup or a bag, it is about the footprint behind it.

What Is It?

This project asks you to compare the environmental impact of a DIY biodegradable plastic, usually made from polyvinyl alcohol, or PVA, plus starch, against PLA and PET. Think of it like comparing three backpacks, not by how they look, but by how much material, fuel, and waste each one needs from start to finish. LCA turns that big picture into numbers.

You are not testing just whether a plastic breaks down. You are asking what it costs the planet to make, use, and dispose of that plastic. A material can seem eco-friendly because it comes from plants or degrades faster, but the upstream steps can still use a lot of energy or water. LCA helps you catch those tradeoffs.

Why This Is a Good Topic

This is a strong science fair topic because you can study a real sustainability question with public data, clear variables, and measurable outputs. You can compare materials, assumptions, and disposal pathways, then see how the answer changes when you switch the system boundary. That gives you room to do real analysis instead of just repeating a summary from a website. It also connects to packaging, waste, and green chemistry, so the project has a clear real-world purpose.

Research Questions

• How does the cradle-to-gate carbon footprint of DIY PVA-starch plastic compare with PLA and PET?
• What is the effect of changing the disposal route from landfill to industrial composting on the total impact score of each plastic?
• Does the choice of electricity mix change which material has the lowest climate impact?
• To what extent does the starch fraction in the DIY blend affect the material's overall life-cycle footprint?
• Which life-cycle stage contributes most to the total impact for PVA-starch, PLA, and PET?
• How does the water-use profile of DIY PVA-starch plastic compare with PLA and PET?
• To what extent do transport assumptions change the ranking of the three plastics?

Basic Materials

• Computer with internet access.
• OpenLCA software.
• Public life-cycle inventory datasets from government, nonprofit, or open-access sources.
• Spreadsheet software such as Google Sheets or LibreOffice Calc.
• Notebook for tracking system boundaries, assumptions, and citations.
• Basic calculator.
• Reference sources for polymer properties, disposal methods, and material densities.
• Simple diagramming tool for mapping your life-cycle stages.

Advanced Materials

• Computer with internet access and enough storage for LCA databases.
• OpenLCA software.
• University library access for review articles on polymer LCA.
• Laboratory balance for measuring sample mass if you also make test films.
• Digital caliper or micrometer for film thickness checks.
• Tensile testing access if you want to link impact to material performance.
• Microscope or optical imaging setup for checking film uniformity.
• Statistical software or scripting environment such as Python for sensitivity analysis.

Software & Tools

• OpenLCA: Builds the life-cycle model, compares scenarios, and calculates impact categories.
• Google Sheets: Organizes inventory data, assumptions, and sensitivity tables.
• LibreOffice Calc: An offline spreadsheet option for data cleaning and charts.
• Python: Helps you run sensitivity checks and graph scenario comparisons.
• ImageJ: Measures film thickness or defect size if you collect your own material images.

Experiment Steps

1. Define the exact plastics you will compare, the product unit, and the life-cycle boundary.
2. Choose impact categories that match your question, such as climate change, water use, and fossil resource demand.
3. Build separate LCA models for the DIY plastic, PLA, and PET using the same functional unit.
4. Plan a sensitivity analysis so you can test how much your answer changes when assumptions change.
5. Check which process stage drives each result, then identify the hotspot that matters most.
6. Prepare clear graphs and a methods summary that explain every assumption you made.

Common Pitfalls

• Comparing one kilogram of each plastic instead of the same service unit, which makes the result unfair.
• Mixing cradle-to-gate data for one material with cradle-to-grave data for another, which breaks the comparison.
• Using vague household recipe data for PVA-starch without documenting the exact formulation, which makes the model impossible to defend.
• Ignoring disposal pathways, which can hide major differences between PLA, PET, and DIY blends.
• Treating one database value as a fact, which can make the project ignore uncertainty and sensitivity.

What Makes This Competitive

A stronger project will do more than rank three plastics. You can push it by testing how sensitive the results are to electricity mix, transport distance, disposal method, and material recipe. You can also compare more than climate impact and look for tradeoffs across water, fossil energy, and waste. A clean methods section and careful assumptions matter as much as the final chart.

Project Variations

• Compare film packaging instead of rigid containers, so your functional unit matches a real use case.
• Swap the DIY blend for another biopolymer recipe, such as starch-glycerol film or cellulose-based film.
• Add a performance lens by pairing the LCA with simple strength, flexibility, or moisture resistance tests.

Learn More

• OpenLCA Nexus documentation: Learn how life-cycle models are structured and where to find datasets in the OpenLCA ecosystem.
• EPA Sustainable Materials Management: Read background on material footprints, waste, and recycling pathways on the EPA website.
• USGS Materials Flow Analysis: Use government data to understand how material extraction and use are tracked in the United States.
• NASA Earthdata: Find environmental data tools and context for broader sustainability analysis on NASA Earthdata pages.
• PubMed: Search review articles on bioplastics, PLA, PVA, starch blends, and polymer life-cycle assessment.
• MIT OpenCourseWare: Look for free coursework in environmental engineering, systems analysis, and sustainability modeling.