Desenvolvimento de adesivo à base de amido de milho e mandioca

Corn and native cassava starch were modified by oxidation and acid hydrolysis, aiming to develop paper and paperboard stickers. The oxidation was made with Sodium hypochlorite (NaOCl) in two distinct concentrations of active chloride which is present on oxidizing agent solution. The synthesis resulting products were used to make stickers and they were compared to corn and cassava starch based stickers without any modification, as well as commercial stickers based on polyvinyl acetate (PVA). Two different methodologies were tested using acid hydrolysis to modify corn and cassava starch, both using phosphoric acid (H3PO4) in order to obtain dextrin and subsequently use it in the production of stickers and also comparing them to petrochemical-based commercial stickers. Considering the different starch modifications methods (oxidation and acid hydrolysis), stickers based on renewable raw material were obtained, which combine biodegradability, low costs and availability.Amidos de milho e de mandioca nativos foram modificados por oxidação e hidrólise ácida, visando desenvolvimento de adesivos para papel e papelão. A oxidação foi realizada com hipoclorito de sódio (NaOCl) em duas concentrações distintas de cloro ativo presente na solução de agente oxidante. Os produtos obtidos foram utilizados para a preparação de adesivos, comparados com adesivos produzidos com amidos de milho e mandioca sem modificação, e com adesivos comerciais à base de acetato de polivinila (PVA). Para a hidrólise ácida, foram utilizadas duas diferentes metodologias para modificação do amido de milho e de mandioca, ambas utilizando ácido fosfórico (H3PO4), para obtenção de dextrinas e posteriormente utilização na produção de adesivos comparando também aos adesivos comerciais de base petroquímica. Com as diferentes modificações (via oxidação e hidrólise ácida) dos amidos, obtiveram-se adesivos baseados em matérias-primas renováveis que aliam biodegradabilidade, baixo custo e disponibilidade

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora