Authors: Hannu Ilvesniemi (LUKE), Jukka Niskanen (Aalto yliopisto), Laura Äkräs (Aalto yliopisto), Marjatta Vahvaselkä (LUKE), Frans Silvenius (LUKE), Kari Kolari (VTT)
Are bio-based alternatives to fossil-based plastics more sustainable solutions for the environment? This is one of the key questions we wanted to examine in the ValueBioMat project. Specifically, we wanted to determine the environmental impact of these alternative options compared to traditional solutions. Life Cycle Assessment (LCA) is a comprehensive and useful tool for such an examination. We chose to examine biobased polyesters and nylons and composites thereof, to get some relevant answers and solutions for applicable products.
The global reliance on petroleum-based nylons (polyamides), and other plastics, pose significant environmental challenges, including high carbon emissions if the waste is not recycled, non-biodegradability, and dependency on finite fossil resources. This issue is particularly critical in industries such as automotive, textiles, and packaging, where the use of nylons is extensive. Furthermore, the lack of sustainable alternatives with comparable mechanical and thermal properties perpetuates this environmental burden.
Biobased nylon composites can reduce our dependency on fossil-based nylons and composites thereof. Fillers in composites play a significant role in providing the composites its material properties but also in reducing the carbon footprint. Renewable fillers, such as lignin, cellulose, and biochar can all be used to reinforce nylons and reduce their carbon footprint. In addition, carbon- or silicon-based particles (graphene, silicon dioxide) can be used to further enhance the properties of nylons by improving their barrier properties, which are important in packaging applications. However, care should be taken so that the carbon footprint and other environmental impacts do not exceed those of the traditional materials.
The environmental impacts of biobased plastics may not be lower than those based on fossil raw materials. The results from our LCA examinations highlighted the differences in the environmental impact between fossil-based and biobased plastics. It should be noted that the assessment also showed that the differences are highly case-specific.
We also found that the environmental impacts of biobased plastics can be reduced by preparing composite materials from them with suitable fillers. In this study, the environmental impacts of composite plastics made from biobased plastics and fillers such as starch or biochar were significantly smaller than those of pure biobased plastics. Moreover, the mechanical properties of composite plastics, such as tensile strength and impact resistance, were at least as good, if not better, than those of pure biobased plastics.
Life cycle assessment is a comprehensive approach in assessing the environmental impact of a product, process, or service throughout its entire life cycle (from cradle to grave) or, for example, during the production and manufacturing of plastics (from cradle to gate). Comprehensive life cycle assessment considers all stages, from the production and procurement of raw materials, transportation, product manufacturing, to its disposal or recycling, and encompasses multiple environmental impact categories. It analyzes the energy consumption, resource use, and environmental effects of each stage.
The applications of life cycle assessment include product development and marketing for businesses that cover the entire production chain, decision-making processes related to permits, taxes, fees, and legislation for policymakers, and providing consumers with objective information for making environmentally friendly choices and lifestyles. It is important to note that comparing life cycle assessments can be challenging, as the results are heavily dependent on the requirements, constraints, and scope set for the analysis. However, comparing within the same life cycle assessment is generally considered reliable, and harmonized international guidelines specific to product groups are under development.
To achieve a widespread shift to sustainable alternatives for plastics, a coordinated action by multiple stakeholders is vital, as the major obstacles are cost competitiveness, infrastructure gaps, environmental effects and regulation, but also land use and concerns over competition with food production. Academia and research institutions must work towards optimizing biocomposite formulations to achieve cost-effectiveness but most of all performance on par with fossil-based materials. This must be conducted in close collaboration with industrial stakeholders to drive innovations in manufacturing and scalable production of biocomposites. The solution can be also such that the backbone of the plastic is fossil and fillers biobased.
The research in ValueBioMat provided comprehensive and practical information on the factors to consider in actions related to replacing traditional plastics in each example product group. However, further investigation is needed for new products (such as plastics, fillers, and reinforcements) and their environmental impacts. More research is especially necessary to better account for the changes in biomass and soil carbon stocks related to the production of biobased products (including both carbon emissions and sequestration) in product-level environmental impact assessments. In addition, the utilization of by-products and waste streams to produce monomers or fillers for bio-based plastics and composites should be investigated and evaluated with fossil-based alternatives and recycled plastics. Another question is that when does it make sense to substitute fossil-based with bio-based plastics to minimize environmental impacts? We also need to consider what is good enough, i.e. to have the right material for the right application and designing for recycling, to minimize waste and other environmental impacts.
If you wish to hear more, register to our final seminar on June 6th 2025 at Saastamoisen säätiö V002/Ekonominaukio 1, Espoo, Finland. Activities – ValueBioMat