Contribuição da xilana para as propriedades físico-químicas e de biodegradação em bioplásticos à base de amido.

• Ano de defesa: 2021
• Autor(a) principal: Macedo, João Victor Carpinelli
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Bioplastic; Biomass; Ciências biológicas; Biopolímeros; Polissacarídeos; Biomassa vegetal
• Link de acesso: http://hdl.handle.net/11449/214701

Plastic has served society very well for decades, being able to present itself as a light and moldable material, mechanically and thermally resistant, inert to chemical products, electrical insulator, in addition to having interesting optical characteristics such as its transparency. Such characteristics, associated with the low price of its raw material, a residue from the processing of petroleum until then little used, made it crucial for the industry and the market, which consolidated its presence in society in different countries. However, as it is a resistant material, remaining for centuries without fully decomposing, and for having a large production in order to meet the needs of a consumer society, it began to accumulate in the environment over the years since its creation. Its abundance in the environment causes damage to life in different biomes, especially marine environments, in addition to having residues that can be toxic and reach humans through the food chain. A possible solution is biodegradable materials that use renewable raw materials such as proteins, lipids, and polysaccharides, the so-called bioplastics. In this context, the present study aimed to produce bioplastics based on starch with different proportions of xylan extracted from sugarcane bagasse and glycerol as a plasticizer. For this, their physicochemical properties (solubility, hydrophilicity, moisture, water barrier, opacity, crystallinity, and mechanical resistance) were evaluated. The biodegradation of the bioplastic was determined by buried and CO2 released. As a result, it was observed that the increase in the proportion of xylan made the bioplastics more soluble in water, susceptible to enzymatic attack by microorganisms, and opaque. Through of the contact angle test, the bioplastic with starch and plasticizer showed lower affinity to water compared to the one including xylan, which among them the proportion of 25 % (w/w of the polysaccharides) was the least hydrophilic. Bioplastic with 5 % (w/w of polysaccharides) xylan showed better crystallinity followed by starch. As for its mechanical strength, the bioplastic with 10 % xylan (w/w of polysaccharides) owned the highest tensile stress (2.56 MPa), but the presence of xylan considerably reduced its elongation at break (ranging from 16 to 37 %) in relation to the starch bioplastic (208.8 %). In general, after 30 days of burial, the bioplastics had practically no fragments visible to the naked eye, and the rate of CO2 production together with the increase in cell count after the biodegradation period demonstrate that there was an effective catabolic action of the microorganisms in the bioplastics. Thus, the 5 % xylan bioplastic showed the best physicochemical results when obtaining a biodegradable material.