6 documents found, page 1 of 1
NANOCRISTAIS DE CELULOSE A PARTIR DE CELULOSE BACTERIANA
Lima,Lais R.; Santos,Daniele B.; Santos,Molíria V.; Barud,Hernane S.; Henrique,Mariana A.; Pasquini,Daniel; Pecoraro,Edison; Ribeiro,Sidney J. L.Bacterial cellulose produced from Gluconacetobacter xilinus was used to produce cellulose nanocrystals by sulfuric acid hydrolysis. Hydrolysis was performed with 64% sulfuric acid at 50 ºC with the hydrolysis time ranging between 5 and 90 min. The production of nanocrystals was observed to have size distributions that were dependent on hydrolysis times up to 10 min, after which time the suspensions showed distr...
Synthesis and Characterization of Methylcellulose Produced from Bacterial Cellu...
Oliveira,Rafael L.; Vieira,Júlia G.; Barud,Hernane S.; Assunção,Rosana M. N.; R. Filho,Guimes; Ribeiro,Sidney J. L.; Messadeqq,YounesIn this work, methylcellulose (MC) was produced from bacterial cellulose (BC), using dimethyl sulfate in a 3 h (MC3h) or 5 h (MC5h) reaction under heterogeneous conditions, with reagent substitution at each hour. MC3h showed a degree of substitution (DS) of 2.26 ± 0.13 and MC5h showed a DS of 2.33 ± 0.05. The two samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffract...
Bacterial cellulose as a template for preparation of hydrotalcite-like compounds
Perotti,Gustavo F.; Barud,Hernane S.; Ribeiro,Sidney J. L.; Constantino,Vera R. L.Bacterial cellulose (BC) was used as a template for preparation of Hydrotalcite-type compounds or layered double hydroxides (LDHs) by co-precipitation method, and submitted to three aging times. Isolated composites containing LDH supported on BC (BC-LDH) were calcined to remove the organic matrix. Mixed metal oxides formed after thermal decomposition underwent reconstruction reaction in Na2CO3 solution producin...
Biossíntese e recentes avanços na produção de celulose bacteriana
Donini,Ígor A. N.; Salvi,Denise T. B. De; Fukumoto,Fabiana K.; Lustri,Wilton R.; Barud,Hernane S.; Marchetto,Reinaldo; Messaddeq,YounesO presente trabalho discute os recentes avanços na biossíntese e na produção de celulose bacteriana (CB) pela gram-negativa, aeróbia e aceto-ácida Gluconacetobacter. xylinus. A CB se difere de seu par vegetal, principalmente devido ao seu caráter de fibras nanométricas, contra o caráter micrométrico da vegetal, são extruídas através da parede celular de G. xylinus, com isso sua estrutura macroscópica é mecanica...
Preparation and antibacterial activity of silver nanoparticles impregnated in b...
Maria,Luiz C. S.; Santos,Ana L. C.; Oliveira,Philippe C.; Valle,Aline S. S.; Barud,Hernane S.; Messaddeq,Younés; Ribeiro,Sidney J. L.A simple method was developed to load a large amount of silver nanoparticles into bacterial cellulose (BC) produced by Gluconacetobacter xylinus in a controlled manner. Due to the high electron-rich oxygen density in the BC macromolecules and the large surface area of the BC nanoporous structure as an effective nanoreactor, the in situ direct metallization technique was successfully used to synthesize Ag nanopa...
Preparation and bactericidal effect of composites based on crosslinked copolyme...
Maria,Luiz C. de S.; Oliveira,Rachel O.; Merçon,Fabio; Borges,Maria E. R. S. P.; Barud,Hernane S.; Ribeiro,Sidney J.L.; Messaddeq,Younés; Wang,Shu H.Commercial copolymers based on styrene and divinylbenzene containing sulfonic acid groups were used as support for the incorporation of silver nanoparticles. These nanoparticles were obtained in situ by the reduction of Ag+ by using hydroxylamine in the presence of a protective agent. These materials were characterized with determination of the silver content and their morphological characteristics. The antibac...