Engineering | Using starch, polyvinyl alcohol, and natural additives, researchers developed a material with functional properties and improved moisture resistance
*Photo: Research Archive
Developed at the Polymer Materials Laboratory (Lapol) within UFRGS’s Sustainability Center, a master’s research project conducted by Helen Kotekewis proposes an alternative to commodity plastic: a biodegradable model.
Today, plastic represents a major environmental challenge, due to its short life cycle and low recyclability. Brazil, for example, is the world’s fourth-largest producer of plastic waste, yet recycles only 24.5% of it.
Helen saw the inspiration for her master’s project in one of the planet’s primary problem. Early on, she had identified the packaging industry as a major source of environmental pollution — largely due to the short time between production and disposal.
“The goal is to replace it [commodity plastic] with something biodegradable. That way, there will be no environmental impact, since the alternative packaging material will break down naturally within a natural cycle”
Helen Kotekewis
Her project has developed a biodegradable film capable of replacing commodity plastic in flexible packaging. Especially for the largest consumers of such materials: the food sector, which is responsible for 20% of plastic production in Brazil.
By combining starch (a natural polymer extracted from corn) with polyvinyl alcohol (PVA, a synthetic polymer), Helen has created a material that is not only biodegradable but also more resistant to moisture and functionally active in preserving food.
This polymer blend — a term used for mixtures of different polymers — also incorporates natural additives such as lignin (a byproduct of the paper industry with antioxidant and antifungal properties) and as malic acid (found in fruits like apples).
Process and results
Throughout her research, Helen has tested different formulations and production methods to identify the most effective composition: a blend containing 75% starch and 25% PVA, supplemented with lignin and malic acid. The choice of additives balanced technical performance with cost-effectiveness.
Beyond significantly reducing moisture absorption — a key requirement for flexible packaging — the additives have also improved the material’s mechanical properties and introduced antifungal and antioxidant effects, all without compromising transparency or biodegradability.
The addition of lignin led to improved mechanical and thermal performance, reduced moisture absorption by up to 35%, and enhanced antifungal and antioxidant activity — features particularly relevant for food preservation.
Malic acid has contributed to a further reduction in moisture (up to 30%) while maintaining the film’s transparency, an important factor for commercial applications.
When combined, these additives have produced a material with high water resistance, a lack of toxic environmental impact, and full biodegradability.
Using relatively accessible techniques, the study demonstrates how industrial residues and natural substances can become sustainable solutions for urgent environmental challenges.
The study points to a real way to reduce the environmental impact of the disposal of short-lifecycle polymers.
Plastic in the environment
Plastic waste is a global issue, and the food industry is one of its largest users. A quick trip to the supermarket makes this clear: aside from some paper or aluminum packaging, most food products are wrapped in plastic that is quickly discarded.
“The packaging industry is one of the biggest polluters because of the short time between production and disposal. In Brazil, this is one of our most pressing environmental problems”
Helen Kotekewis
Until the 1970s, global plastic production was relatively low. Since then, it has grown faster than any other material. In the early 2000s alone, plastic waste increased more in a single decade than in the previous 40 years combined.
Some plastics, such as PET (polyethylene terephthalate, type one plastic), are more easily recyclable and less prone to downcycling (the loss of material quality during recycling). However, flexible and multilayer packaging, which combine different polymers, are far more difficult to recycle and often end up in landfills.
“We’ve always heard that we need to preserve the environment, but now the consequences are more visible in everyday life”
Helen Kotekewis
According to the Panorama of Solid Waste in Brazil, each Brazilian generates an average of 842 pounds of solid waste per year. Although recycling rates have increased, they still represent only about 8% of total waste. Much of what is recycled is collected by informal waste pickers; only about one-third comes from official selective collection systems.
Looking ahead
Although still at the laboratory stage, the study sends a clear message: it is possible to develop more sustainable materials without sacrificing performance. The next challenge lies in scaling up, turning innovation into public policy and accessible technology so that sustainability becomes the norm rather than the exception.
In the context of an escalating climate and environmental crisis, Helen’s research highlights the transformative potential of applied science, bringing together technical expertise, environmental awareness, and innovation. “It’s not just about finishing a research project, but also about creating real solutions for real-world problems. Impact only happens when science leaves the lab and reaches people,” Helen concludes.
Thesis title: Biodegradable starch/PVA blends with added lignin and malic acid for application in flexible packaging
Author: Helen Kotekewis
Supervisor: Ruth Marlene Campomanes Santana
Program/Unit: Postgraduate Program in Mining, Metallurgical and Materials Engineering – School of Engineering
Translated into English by Alice de Freitas Castro, undergraduate student enrolled in the course “Supervised Translation Training I (English)” of the Undergraduate Program in Language and Literature, under the supervision and translation revision of Professor Elizamari R. Becker (P.h.D.) – IL/UFRGS.
:: Read in portuguese
Estudo desenvolve filme biodegradável como alternativa ao plástico convencional em embalagens