Spray-coated bioplastics offer scalable, sustainable alternative to plastic packaging
Researchers develop a proof-of-concept process to strengthen biodegradable paper coatings and reduce plastic waste.
(From left) Kihyeon Ahn and Chenxi Cao, two graduate students, work in Young Kim's lab on Virginia Tech's Blacksburg campus. Photo by Max Esterhuizen for Virginia Tech.
Research at a glance
Context
Plastic-coated paper is hard to recycle and replace because of technical limits in performance and processing.
Solution
Producers need sustainable packaging that matches plastics in function and ease of production.
Impact
Virginia Tech developed a spray-coated bioplastic that strengthens paper and enables scalable, sustainable packaging.
Virginia Tech researchers have developed a scalable method for creating stronger, more sustainable paper packaging.
Using a novel spray-coating technique, the team in the College of Natural Resources and Environment proved that biodegradable bioplastics can form durable, protective films on paper, a step toward reducing the world’s dependence on petroleum-based plastics.
The proof-of-concept study, led by Young-Teck Kim, associate professor of sustainable biomaterials and affiliated faculty member of the Macromolecules Innovation Institute, demonstrates how spray-coated layers of bioplastics can improve the strength and barrier properties of paper packaging while maintaining its compostability.
“We wanted to show that a sustainable, bio-based multilayer structure could perform like traditional plastic packaging but be easier to manufacture and better for the environment,” Kim said. “Our process improves performance and can integrate directly into existing paper production systems, which means it could be adopted by industry with minimal change.”
The research, conducted in collaboration with Zhiwu Wang and Haibo Huang in the College of Agriculture and Life Sciences as well as Su Jung Hong of Kyung Hee University and other partners, was published recently in Progress in Organic Coatings and supported by the U.S. Department of Agriculture's National Institute of Food and Agriculture.
A cleaner, faster way to coat paper
In conventional packaging production, paper is often coated with plastic films to improve its durability and water resistance, a process that can make the material difficult to recycle. Kim’s team used a spray-coating method that replaces the slow and energy-intensive extrusion process typically used to apply bioplastics such as polylactic acid (PLA) and polyhydroxyalkanoate (PHA). By integrating the spray step into paper manufacturing, the method could reduce material waste and energy use while improving coating consistency.
“Traditional plastic coating methods lead to uneven layers and wasted material, including poor performance in packaging,” Kim said. “Our spray process achieves even coverage down to five microns thick and can be incorporated into the paper mill process with only one additional process.”
Kihyeon Ahn works in Young Kim's lab on Virginia Tech's Blacksburg campus. Photo by Max Esterhuizen for Virginia Tech.
Strength and sustainability combined
The research team found that blending the two bioplastics provided complementary benefits. PLA formed a dense surface layer that sealed the paper’s pores, while PHA penetrated the fibrous structure to enhance internal strength. A 50/50 blend achieved the most balanced results, improving tensile strength and oxygen resistance, two critical factors for packaging longevity and food preservation.
The resulting coated papers showed stronger mechanical properties, improved water resistance, and enhanced thermal stability while remaining biodegradable. Compared with uncoated paper, the spray-coated samples were up to twice as strong and had dramatically lower oxygen transmission rates.
Toward next-generation packaging
While the initial study used organic solvents to test the feasibility of the spray process, Kim said the next step for the research team is to develop a water-based, solvent-free version that will further increase environmental safety and industrial viability.
“This was a proof of concept because we had to start somewhere to test whether the idea would work,” Kim said. “Now that we know it does, our next goal is to move away from organic solvents and toward a water-based coating process that could be safer and easier to scale.”
The work has also attracted the attention of a global chemical company interested in exploring commercial applications. Kim believes the innovation could help transform how the packaging industry approaches sustainability.
“With this approach, we can make packaging that protects products, performs well, and still returns safely to the environment,” he said. “That’s the kind of change we need if we want to move beyond single-use plastics.”
Original study: DOI: 10.1016/j.porgcoat.2025.109685
