Nanocompósitos quitosana/polietilenoglicol/laponita no tratamento de sementes

• Ano de defesa: 2023
• Autor(a) principal: Lima, Kelly Santana
• Orientador(a): Sarmento, Victor Hugo Vitorino
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Química
• Palavras-chave em Português: Nanocompósitos (Materiais); Polímeros; Minerais de argila; Tecnologia de sementes; Hidrogéis; Argilominerais; Revestimentos de sementes
• Palavras-chave em Inglês: Hydrogels; Clay minerals; Seed coatings
• Área do conhecimento CNPq: CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: http://ri.ufs.br/jspui/handle/riufs/17716

The commercial use of laponite and chitosan, in an environmentally friendly way and aiming at sustainable materials, is a new challenge to be considered in the bioeconomy. Polymer/clay nanocomposites are a class of organic/inorganic materials that have shown vast application in several areas, such as the coating of seeds that can be used in their protection, hydration or release of agrochemicals. In this work, we sought to synthesize and study polymer/clay nanocomposites based on polyethylene glycol (PEG), chitosan and laponite, aiming at its use in seed treatment. To build the theoretical foundation and the state of the art, the study started by prospecting the technological basis of the use of the main substances used in the nanocomposite and their properties, through a systematic review. The Bibliometrix package of the R software was used for the biometric analysis of the publications. The prospection of patents was carried out in the Lens database. For this, 132 publications were prospected in the scientific databases Scopus (53) and Web of Science (WoS) (79). No publications using laponite and chitosan combined for seed coating were found in these platforms. The materials were then characterized by absorption spectrophotometry in the infrared region (FTIR), thermal and rheological analysis, and coating of lettuce and corn seeds. Polymer/clay nanocomposites were prepared and showed improved thermal properties. The nanocomposites, regarding their rheological characteristics, showed that the chitosan interferes directly in the maximum deformation supported by the samples. There was the composition of a cross-linked system and little fluid, suitable for application as a coating on seeds. The potential use of the nanocomposite was tested on lettuce and corn seeds submitted to the germination test. Lettuce seeds treated with P12Q6L09 and P12Q45L0 nanocomposites showed 100% germination rate, higher than the control. As for corn seeds, samples P12Q0L0 and P12Q0L09 showed the best germination rates, 91 and 95%, respectively, while the control obtained 83%. Therefore, the samples present potential use as coatings for these propagules and showed different results in different crops.