Daniel Cerqueira

1 Instituto de Quımica da Universidade Federal de Uberlâ ndia, Av. Joa˜ o Naves de A´ vila 2121, CEP 38400-902, Cx. P. 593, Uberlâ ndia-Minas Gerais, Brasil ... 2 Departamento de Fısica e Quımica da Universidade de Caxias do Sul-Caxias do Sul, Rio Grande do Sul, Brasil

Membranes of blends of polyaniline (PANi) and cellulose acetate (CA) produced from sugarcane bagasse with different degrees of substitution were produced and characterized using various techniques. Results showed that incorporation of PANi into the CA matrices leads to significant alterations of the blend morphologies, with phase separation, and that these differences are less significant for PANi/cellulose triacetate blends. The blends

In this work, the viability of recycling newspaper for producing cellulose acetate was tested. Newspaper recycling is extremely important not only for the environment preservation, but also from the economical point of view of aggregating value to this residue. Cellulose acetate was produced from a homogeneous acetylation, and then characterized by FTIR, DSC and TGA. Acetylation times were 48 h for as received newspaper (CA48) and 24 h for delignified newspaper (CA24), resulting in cellulose diacetate (DS = 1.98 ± 0.22) for CA48 and cellulose triacetate (DS = 2.79 ± 0.02) for CA24, respectively. Membranes of these materials were produced and characterized according to the previously mentioned techniques and by measurements of water vapor flux, which were compared to membranes of nanofiltration SG from Osmonix®. Results showed that independently of a purification step, it is possible to produce cellulose acetate membranes through the chemical recycling of newspaper and that membrane CA24 presents thermal stability comparable to membranes produced of commercial cellulose acetate.

In the present study the reaction of heterogeneous acetylation was applied to sugar cane bagasse. The product of heterogeneous acetylation was characterized using: (a) Fourier transformed infrared (FT-IR) spectroscopy based on the presence of the CO stretch band of the carbonyl group (around 1740 cm−1), (b) wide angle X-ray scattering (WAXS) based on the presence of a maximum in the region of 2θ between 5 and 10°, and (c) differential scanning calorimetry (DSC) based on the presence of an endothermic peak at approximately 300°C. The acetate produced was cast into films and the water flux was measured by the cup technique of Payne. The water flux through films of 50 μm was (9.10±0.06)×10−7 g s−1 cm−2.

In this work we performed an optimization process of the acetylation reaction of sugarcane bagasse cellulose. The optimization was carried out varying acetic acid, acetic anhydride and catalyst volume, as well as reaction and activation times. Intrinsic viscosity was used as parameter for determining the quality of the produced material. Cellulose acetate viscosity-average molecular weight increased from 5.5 × 103 to 55.5 × 103 g mol−1.

In the present work, methylcellulose produced from sugar cane bagasse was characterized by FTIR, WAXD, DTA and TGA techniques. Two samples were synthesized: methylcellulose A and methylcellulose B. The only difference in the process was the addition of fresh reactants during the preparation of methylcellulose B. The ratio between the absorption intensities of the C–H stretching band at around 2900 cm−1 and O–H stretching at around 3400 cm−1 for methylcellulose B is higher than for methylcellulose A, indicating that methylcellulose B showed an increase in the degree of substitution (DS). Methylcellulose A presents a more heterogeneous structure, which is similar to the original cellulose as seen through FTIR and DTA. Methylcellulose B showed thermal properties similar to commercial methylcellulose. The modification of methylcellulose preparation method allows the production of a material with higher DS, crystallinity and thermal stability in relation to the original cellulose and to methylcellulose A.

1 Instituto de Quımica da Universidade Federal de Uberlâ ndia, Av. Joa˜ o Naves de A´ vila 2121, CEP 38400-902, Cx. P. 593, Uberlâ ndia-Minas Gerais, Brasil ... 2 Departamento de Fısica e Quımica da Universidade de Caxias do Sul-Caxias do Sul, Rio Grande do Sul, Brasil

Membranes of blends of polyaniline (PANi) and cellulose acetate (CA) produced from sugarcane bagasse with different degrees of substitution were produced and characterized using various techniques. Results showed that incorporation of PANi into the CA matrices leads to significant alterations of the blend morphologies, with phase separation, and that these differences are less significant for PANi/cellulose triacetate blends. The blends

In this work, the viability of recycling newspaper for producing cellulose acetate was tested. Newspaper recycling is extremely important not only for the environment preservation, but also from the economical point of view of aggregating value to this residue. Cellulose acetate was produced from a homogeneous acetylation, and then characterized by FTIR, DSC and TGA. Acetylation times were 48 h for as received newspaper (CA48) and 24 h for delignified newspaper (CA24), resulting in cellulose diacetate (DS = 1.98 ± 0.22) for CA48 and cellulose triacetate (DS = 2.79 ± 0.02) for CA24, respectively. Membranes of these materials were produced and characterized according to the previously mentioned techniques and by measurements of water vapor flux, which were compared to membranes of nanofiltration SG from Osmonix®. Results showed that independently of a purification step, it is possible to produce cellulose acetate membranes through the chemical recycling of newspaper and that membrane CA24 presents thermal stability comparable to membranes produced of commercial cellulose acetate.

In the present study the reaction of heterogeneous acetylation was applied to sugar cane bagasse. The product of heterogeneous acetylation was characterized using: (a) Fourier transformed infrared (FT-IR) spectroscopy based on the presence of the CO stretch band of the carbonyl group (around 1740 cm−1), (b) wide angle X-ray scattering (WAXS) based on the presence of a maximum in the region of 2θ between 5 and 10°, and (c) differential scanning calorimetry (DSC) based on the presence of an endothermic peak at approximately 300°C. The acetate produced was cast into films and the water flux was measured by the cup technique of Payne. The water flux through films of 50 μm was (9.10±0.06)×10−7 g s−1 cm−2.

In this work we performed an optimization process of the acetylation reaction of sugarcane bagasse cellulose. The optimization was carried out varying acetic acid, acetic anhydride and catalyst volume, as well as reaction and activation times. Intrinsic viscosity was used as parameter for determining the quality of the produced material. Cellulose acetate viscosity-average molecular weight increased from 5.5 × 103 to 55.5 × 103 g mol−1.

In the present work, methylcellulose produced from sugar cane bagasse was characterized by FTIR, WAXD, DTA and TGA techniques. Two samples were synthesized: methylcellulose A and methylcellulose B. The only difference in the process was the addition of fresh reactants during the preparation of methylcellulose B. The ratio between the absorption intensities of the C–H stretching band at around 2900 cm−1 and O–H stretching at around 3400 cm−1 for methylcellulose B is higher than for methylcellulose A, indicating that methylcellulose B showed an increase in the degree of substitution (DS). Methylcellulose A presents a more heterogeneous structure, which is similar to the original cellulose as seen through FTIR and DTA. Methylcellulose B showed thermal properties similar to commercial methylcellulose. The modification of methylcellulose preparation method allows the production of a material with higher DS, crystallinity and thermal stability in relation to the original cellulose and to methylcellulose A.