Disposable packaging produced from non-renewable sources has contributed to various environmental problems ranging from the non-renewal of raw materials to the inadequacy of public policies regarding landfill installations, proper waste separation, and selective collection disposal. Furthermore, petroleum-derived plastic does not decompose in a timely manner, and often some varieties are not economically viable for recycling, accumulating in rivers and public places.
Therefore, there is a significant effort to find packaging that minimizes environmental impact, maintains the characteristics of the packaged product, and is economically accepted in the petroleum polymer market.
The use of biodegradable packaging is seen as a great option to minimize the deposition of long-lasting materials in the soil, as materials made from biopolymers decompose upon contact with microorganisms under favorable moisture and water conditions, which also poses one of the biggest challenges in developing a new material for the industry, such as packaging for non-dry products.
Currently, research on biodegradable packaging has primarily utilized biopolymers, those obtained from large-scale planting varieties such as sugarcane, corn, or potatoes. Biopolymers, such as those derived from starch, are composed of monomeric units designated as sugars, amino acids, and nucleotides, of biological origin. Those we currently know as synthetic, obtained from petroleum, are made from ethylene, butadiene, or even propylene monomers.
The first scientific works in search of biodegradable packaging were based on replacing part of the synthetic matrix, generally derived from petroleum, with a starch matrix, where many difficulties were encountered due to the incompatibility of starch with synthetic polymers. In Brazil, two research groups from the State University of Londrina (UEL) are working hard to minimize this incompatibility and have already achieved relevant results in their research. Recently, materials composed of cassava biopolymers and sugarcane fiber were produced for the production of trays for dry products. The use of the new material is still restricted to this type of product due to interactions with air humidity, which can deteriorate it. The complete work of UEL researchers can be checked here and here.
Cellulose, an example of a very resistant natural biopolymer. Source Wikipedia.
Another group of researchers from the same university has also obtained plastics made from cassava to package plant seedlings, to protect fruits, or as soil cover for vegetable production. This group used glycerol as a plasticizer to reduce the rigidity of the plastic and has tested this substance to evaluate whether its degree of purity influences how the plastic interacts with air humidity and environmental gases. Additionally, as the plastic decomposes after some time in contact with the soil, this prevents excessive handling of the seedlings after planting, avoiding possible damage to the roots.
There is still much to be learned about biopolymers, and our country has stood out in efforts to find something that meets consumer needs, offering the same (or better) packaging conditions provided by petroleum polymers. Despite the various lines of action from bioplastic researchers and the contradictions among so many studies, such as which plasticizer would be most suitable for each packaging, both emphasize in their work the importance of producing materials capable of reducing the exchange of gases and water between the packaged product and the environment, delaying food spoilage and preventing the growth of microorganisms. They also highlight the importance of finding a plasticizer that meets the physiological needs of the products as well as the economic needs of the country, which will not exchange decades-old technology without first ensuring that it is stepping on solid ground in bioplastics.
