Researchers at the State University of Sao Paulo (UNESP) in Brazil have developed a film made from industrial waste to replace plastic packaging in food packaging. It is made from bacterial cellulose waste and hydroxypropyl methyl cellulose (HPMC) left over from industrial processes-both of which are sustainable raw materials.

When the bacterial cellulose nanocrystals and HPMC are combined, they become biodegradable films with better performance than films made from HPMC alone.

Co-author Márcia Regina de Moura Aouada is a researcher at the Functional Materials Development Center and holds a PhD. The PhD in Chemistry from UNESCO said:

We started filling the HMPC matrix with bacterial cellulose nanocrystals to enhance its performance. We also want to formulate a more environmentally friendly agreement for the development of new composite materials, from the material itself to its source, so we include the reuse of industrial waste in the project.

Aouada is dedicated to researching films made from renewable energy sources and biodegradable and edible films. She wanted to find ways to reduce the increasing number of waste plastic food packaging made from unsustainable sources. She led the research.

Pamela Melo, the first author and UNESCO material science graduate student, said:

Compared with traditional films derived from petroleum, one of the limitations of films made from HPMC and other biopolymers is their lower mechanical strength. They also have a high degree of water vapor permeability, which limits the available applications. We have improved these properties by adding bacterial cellulose.

Creating good composite materials is not enough. We need to find the best solution to obtain good film performance by changing factors such as viscosity and nanoparticle concentration. A fair analogy can be a cake recipe: researching recipes is another major innovation in our research.

How the nanocrystals interact with and distribute in the HPMC matrix will determine the quality of the film, so we tested and used Turrax dispersers to achieve the best distribution through high-energy dispersion.

Nanocrystals will not change the transparency of HPMC, which is great. However, this material will absorb moisture, which is currently a limitation for its use in packaging. Nevertheless, the advantages of bacterial cellulose are significant, so researchers will find a solution.

Cellulose is the core component of plant fibers, providing rigidity to plants. It is the most abundant polymer in nature and is often used in papermaking. However, some algae, marine invertebrates and bacteria also secrete cellulose. This cellulose has always been a popular choice for making biofilms for wound dressings. Now, it is expanding to other areas-such as food packaging.

The biggest advantage of using these materials is to protect the natural environment.

Bacterial cellulose can be produced in the laboratory all year round, regardless of weather and environmental conditions. It is a purer molecule and produces less pollution during the production process.

Processing bacterial cellulose does not require the use of toxic substances, which is different from processing plant cellulose, which involves the use of harmful compounds to eliminate impurities.

In addition, bacterial cellulose contains nanofibers in its structure to make it stronger.

This is very interesting because it gives the material unique properties, such as high tensile strength, which means it can withstand certain loads or stresses without breaking.

The next stage of the research is to continue testing film-forming dispersions and research other polymer dispersion technologies, while comparing them with HPMC, and then assessing their biodegradability. The main focus is to develop better film-forming distribution, because if they master this, it is possible to use cellulose on a larger scale.

Our main focus is to find substitutes for materials that are considered ecologically incorrect, such as petroleum products. Such alternatives include biodegradable composite materials derived from renewable resources.

Studies have shown that sugar cane or soybean molasses can be used as a substrate to obtain bacterial cellulose.

The price of products made from cellulose waste will be lower because it reduces processing costs. This may make it cost-competitive with traditional plastic films. This more sustainable packaging must be cheap so that consumers will want to buy it.