In Brazil, researchers at São Paulo State University (UNESP) in Ilha Solteira have developed a film that can replace plastic in food packaging. The film is made from hydroxypropyl methylcellulose (HPMC) and bacterial cellulose scraps left over from industrial processing. Both raw materials are sustainable. They are combined to produce a biodegradable film of bacterial cellulose nanocrystals and HPMC. “We set out to fill the HMPC matrix with bacterial cellulose nanocrystals in order to enhance its properties. We also wanted to create greener protocols for the development of novel composites, from the material itself to its origin, so we included the reuse of industrial waste in the project,” said Márcia Regina de Moura Aouada, a co-author of the article. Aouada has a PhD in chemistry from UNESP, where she teaches and is a researcher at the Center for Development of Functional Materials (CDMF), one of the Research, Innovation and Dissemination Centers (RIDCs) supported by FAPESP.
The researchers obtained bacterial cellulose scraps from Seven Indústria de Produtos Biotecnológicos, which makes wound dressing biofilms in the state of Paraná. To convert this waste into film suitable for food packaging, they first milled the scraps into powder. “We then submitted the powder to sulfuric acid hydrolysis, a process well described in the literature,” Melo said. The result was a bacterial cellulose nanocrystal suspension, which they mixed with HPMC diluted in water to produce a film-forming dispersion, a target of interest for the bioplastics industry. “It’s not enough to create good composites. We need to find the best solution to obtain good film properties by varying factors such as viscosity and nanoparticle concentration. A fair analogy could be a cake recipe: studying the recipe is another significant innovation in our study,” Aouada said.
The researchers plan to continue testing film-forming dispersions until they conclude they have developed a competitive product. They are studying other polymer dispersion techniques, comparing them with the use of HPMC, and assessing their biodegradability. If they succeed in developing better film-forming dispersions, it may be possible to use bacterial cellulose on a larger scale. “Our main focus is on finding substitutes for materials not considered ecologically correct, such as petroleum products. Such substitutes include biodegradable composites derived from renewable resources,” Aouada said.
Source: Eurek Alert!
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