Obtenção e caracterização de nanocelulose a partir de fibras de Chorisia speciosa St. Hil

Natural fibers have been highlighted as a renewable material that can replace materials from oil and its derivatives. In this context, Brazil becomes the perfect setting because of the diversity of fibers found in its territory, such as sugarcane, sisal, rice, cotton, coconut, pineapple, among others. The paineiras (Chorisia speciosa St. Hil) are typically Brazilian trees, which produce paina as fruit. These fruits are still little studied as a source of lignocellulose by research groups. This project aimed obtaining and characterization of cellulose nanofibers from the fibers from the paina fibers. Obtaining nanocellulose is practically made through simplified chemical processes. First, was performed out pre-treatments to removal of waxes, lignin and hemicellulose. The first stage of pre-treatment was carried out by alkaline aqueous solution of sodium hydroxide (NaOH) at 5wt%, where the fibers were under constant agitation for 1h at 70°C. Through alkali treatment it was possible to remove most of the lignin, hemicellulose, waxes and extractives. After the alkaline treatment was done bleaching with an aqueous solution of sodium hydroxide (NaOH) to 4wt% and hydrogen peroxide (H2O2) to 24wt% 1:1 during 2h with constant stirring to 50 °C. Through bleaching was possibe to remove residual lignin, and got cellulose with 72% of crystallinity. Nanocellulose of paina fibers was extracted using different conditions of acid hydrolysis with sulfuric acid (H2SO4) to 50wt%. After acid hydrolysis, the suspensions were centrifuged during 30 min and dialyzed in water to remove excess acid until neutral pH (6-7). Then the suspensions were passed by ultrasonification in an ultrasound 20 kHz during 1h in an ice bath. Untreated, alkalinized and bleached fibers as well as cellulose nanoparticles were characterized by the techniques of thermogravimetry ... (Complete abastract click electronic access below)

Produção de enzimas lignocelulósicas por fermentação em estado sólido por espécimes do gênero Trichoderma para sacarificação do bagaço de cana de açúcar tratado com micro-ondas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo do pH e atividade antimicrobiana sobre Enterococcus faecalis de medicação intracanal à base de hidróxido de cálcio associada ao óleo de melaleuca, clorexidina ou farnesol

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização hidrogeoquímica, isotópica e diagenética do sistema aquífero Bauru no Estado de São Paulo

Pós-graduação em Geociências e Meio Ambiente - IGCE

Análise de um trocador de calor tipo serpentina de uma planta de hipoclorito de sódio

This study aims to analyze the capacity of a helical coil heat exchanger to reach the requested heat transfer rates by a sodium hypochlorite production process. This heat exchanger was installed in an experimental way in order to reuse a source of low-temperatures water in such a way to become a more economical alternative than the existing cooling tower. Firstly, the concepts related to the theory of heat transfer applicable to the case were introduced. Then, the mapping of the main information about the production process and the technical specification of the current cooling system equipment's was realized. Using the dimensions of the heat exchanger installed today as reference, the calculations for determining the ideal length of the coil to different flows of hot fluid were performed. Finally, it was concluded that the heat exchanger currently employed does not provide heat transfer rates required for the maximum flow rate value supported by the cooling tower

Citotoxicidade do ácido peracético: avaliação metabólica, estrutural e de morte em fibroblastos L929

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biocompatibilidade de resinas acrílicas para base e reembasamento de próteses após períodos de imersão em soluções desinfetantes: análise do metabolismo celular

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)