USP engineers create biodegradable plastic

The researchers developed a technique that uses ozone gas to process starch and improve the properties of plastic. The result is a more transparent and resistant product, which can be used in various types of packaging. The method has already had the patent applied for, aiming at the transfer of technology to industry.
"The search for renewable alternatives for the production of biodegradable plastics is increasing, being the focus of the study of several groups of universities worldwide," explains Professor Pedro Esteves Duarte Augusto, coordinator of the Process Engineering Study Group (Ge²P) at ESALQ. "One of the possible raw materials for the production of these plastics is starch, a natural ingredient obtained from vegetables such as corn, cassava, potatoes, rice, among others."
According to the professor, the union of research groups occurred because the production of plastics from starches has been exploited for 15 years by the group of Professor Carmen Cecilia Tadini, of the Laboratory of Food Engineering (LEA) of POLI and the Food Research Center (FoRC), one of the Centers for Research, Innovation and Dissemination (CEPIDS) of the Research Support Foundation of the State of São Paulo (FAPESP). "On the other hand, at Ge²P we have studied, since 2015, different technologies for starch modification and possible applications."
According to Professor Duarte Augusto, although the group has already developed work with ultrasound and irradiation technologies, studies with modification of starches with ozone have resulted in several applications, such as improved expansion in the oven and 3D printing.
Carla points out that the innovative aspect of her project consists in the modification of cassava starch from ozonization to film production. "It is a green technology, friendly to the environment. This is the focus, modifying it with ozone in order to improve its properties in the native form. We produce this biodegradable plastic and, even in the initial stage, we have already obtained a good quality product.
The next step, to be executed at POLI, is production on a semi-industrial scale", he explains. Thus, for the realization of the project, the stages of ozonization, drying and characterization of starch samples are carried out at ESALQ. Next, Carla takes the material to the POLI to prepare and characterize the biodegradable plastic.
Among the benefits of the new product are greater strength, transparency and permeability. "The processing of starches with ozone allowed the production of more resistant and homogeneous plastic films, with different interaction with water and, in some cases, better transparency", details Carla. "These are characteristics of great industrial interest, demonstrating how ozone technology can be useful for the manufacture of biodegradable plastics with better properties than using only native starch."
The engineer recalls that the product should be used on the market in various ways. "The applications are numerous, since more resistant and transparent packaging is desirable in most applications," he says.
A patent application has already been filed to transfer technology to industry.
The results obtained from this study were presented in the scientific paper Ozonation of cassava starch to produce biodegradable films, published in the journal International Journal of Biological Macromolecules.
The study also had the participation of researchers Andressa de Souza, Bianca Maniglia and Nanci Castanha, being financed by FAPESP and the National Council for Scientific and Technological Development (CNPq), with scholarships from FAPESP, CNPq and Coordination for the Improvement of Higher Education Personnel (CAPES).