Glycerol is a plasticizer widely used due to its good plasticization efficiency, great availability, biocompatibility and low exudation. It is a renewable raw material that, when introduced in biodegradable films, promotes significant changes in its properties and, thus, guarantees a wide spectrum of application. In this work, corn straw was used to produce cellulose triacetate films from mixtures with glycerol (10%, 20% and 30%). The films were characterized by X-Ray Diffraction, Scanning Electron Microscopy, Thermogravimetric Analysis, Water Vapor Transport Rate and Water Vapor Permeation. The cellulose triacetate films produced with 20% glycerol have high barrier properties, when compared to films with concentrations 0, 10 and 30%.
Biodiesel purification by water washing has been proved to be an unattractive process from an economic and environmental point of view. In this work, we propose the use of regenerated cellulose membranes from peanut shell as an alternative in the biodiesel purification. The preparation of the membranes was optimized from a central composite design, resulting in dense and non-porous membranes. However, in contact with biodiesel, the membranes undergo expansion due to the retention of methanol, water, and glycerol molecules, allowing the permeation of fatty acid methyl esters. The filtered biodiesel presents quality parameters, such as total ester content of 98.3 ± 1.4% and free glycerol content < 0.02%, in agreement with the main regulatory agencies. The regenerated cellulose membranes from peanut shell are easily prepared, with high repeatability (relative standard deviation (RSD) < 1.8%) and are presented as an economical and environmental solution for the biodiesel purification.
The synthesis of cationic derivatives of hemicelluloses from corn husk was carried out by the reaction of hemicelluloses with 2,3-epoxypropyltrimethylammonium chloride (ETA) in aqueous sodium hydroxide. The characterization of the cationic derivatives was carried out by elemental analysis, Fourier Transformed Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TG/DTA). An important characteristic was the solubility in water of the produced derivatives. This characteristic was used to apply derivatives as auxiliary coagulation with tannin in wastewater treatment for industrial laundries. The results showed that the association of tannin and cationic hemicelluloses (3,200 mg L-1) is important because the turbidity removal was greater than 95% in all range of pH, including alkaline regions. Then it is unnecessary to adjust the pH before the coagulation step.
The aim of this study was to produce membranes using the adapted cuprammonium method. The cellulose utilized was obtained from recycled agroindustrial residues: sugarcane bagasse, corn stover and soybean hulls. The levels of Cu (II) ions in regenerated cellulose membranes produced with cellulose from bagasse, corn stover and soybean hulls were 0.0236 wt%, 0.0255 wt% and 0.0268 wt%, respectively. These levels were approximately 15 times lower than those observed in previous studies (0.3634 wt%). Cellular viability data show that membranes produced from bagasse cellulose do not present toxicity to the cellular cultures studied. These results demonstrate an evolution in production of regenerated cellulose membranes from agroindustrial residues mainly due to a decrease in the Cu (II) ions level, showing the possibility of application of these systems with improved membranes processing.
Cellulose acetates (CA) with different degrees of acetylation were synthesized from cellulose extracted from corn stover. Membranes were prepared for the ultrafiltration process with pure polymers and blend form of CA utilizing a dioxane/acetone system. The membranes were characterized according to their transport properties. The blend form materials presented the best results for application in ultrafiltration experiments. M-TAC/DAC (corn stover triacetate and diacetate) and M-TAC/DAC-Rho (corn stover triacetate and Rhodia diacetate) presented rejection to egg albumin protein of 87.39% and 80.50%, respectively. Thus, MWCO of 45 kDa was determined for these materials.
Hemicelluloses were extracted from corn husk and converted into cationic hemicelluloses using 2,3-epoxypropyltrimethylammonium chloride. The degree of substitution was determined as 0.43 from results of elemental analysis. The cationic derivative was also characterized by Fourier transform infrared spectroscopy and Carbon-13 magnetic nuclear ressonance. The produced polymer was employed as coagulant aid in a sewage treatment station (STS) of the municipal department of water and sewer (Departamento Municipal de Água e Esgoto - DMAE) in Uberlândia-Minas Gerais, Brazil, using Jar test experiments. Its performance was compared to ACRIPOL C10ï›š, a commercial cationic polyacrylamide regularly used as a coagulant at the STS. The best result of the jar-test essays was obtained when using cationic hemicelluloses (10 mg L- 1) as coagulant aid and ferric chloride as coagulante (200 mg L- 1). The resultsof color and turbidity reduction, 37 and 39%, respectively, were better than when using only ferric chloride. These results were also higher than those of commercial polyacrylamide, on the order of 32.4 and 38.7%, respectively. The results showed that the cationic hemicelluloses presented similar or even superior performance when compared to ACRIPOL C10ï›š, demonstrating that the polyelectrolytes produced from recycled corn husks can replace commercial polymers in sewage treatment stations.
Methylcellulose was produced from the fibers of Mangifera indica L. Ubá mango seeds. MCD and MCI methylcellulose samples were made by heterogeneous methylation, using dimethyl sulfate and iodomethane as alkylating agents, respectively. The materials produced were characterized for their thermal properties (DSC and TGA), crystallinity (XRD) and Degree of Substitution (DS) in the chemical route. The cellulose derivatives were employed as mortar additive in order to improve mortar workability and adhesion to the substrate. These properties were evaluated by means of the consistency index (CI) and bond tensile strength (TS) tests. The methylcellulose (MCD and MCI) samples had CI increased by 27.75 and 71.54% and TS increased by 23.33 and 29.78%, respectively, in comparison to the reference sample. Therefore, the polymers can be used to produce adhesive mortars.
Cellulose acetate produced from mango seed fibers cellulose was used as a matrix for preparation of microparticles empty and load with acetaminophen (Paracetamol) in order to evaluate the incorporation of an active agent during the formation of microparticles. The microparticles are characterized by Fourier Transformed Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). The incorporation of paracetamol can be confirmed by the change in value of glass transition temperature (Tg). The formation of microparticles spherical was observed by SEM and showed an average diameter of 1.010 and 0.950 mm for empty and load microparticles respectively.
Cellulose from sugarcane bagasse was used for synthesizing cellulose acetate with different degrees of substitution, which were characterized by ¹H-NMR through the relationship between the peak areas of the hydrogen atoms of the acetate groups (-(C=O)OCH3) and the peaks of the hydrogen bonded to the carbon atoms of the glucosidic rings. Suppression of some signals was carried out in order to remove the residual water resonance in the materials and those related to impurities in cellulose triacetate as well. A deconvolution method for the computation of the degree of substitution of acetylation is proposed. The degrees of substitution for the cellulose samples were 2.94 and 2.60, in good agreement with those obtained by chemical determination through an acid-base titration.
A celulose do bagaço de cana-de-açúcar foi usada para sintetizar acetato de celulose com diferentes graus de substituição, os quais foram caracterizados por ¹H-RMN através da relação entre as áreas dos picos dos átomos de hidrogênio presentes nos grupos acetato (-(C=O)OCH3) e os picos dos hidrogênios ligados aos átomos de carbono dos anéis glicosídicos. A supressão de alguns sinais foi feita para remover sinais de ressonância da água residual nos materiais e também para remover sinais de impurezas no triacetato de celulose. Um método de deconvolução para o cálculo computacional do grau de substituição foi proposto. Os graus de substituição das amostras de acetato de celulose foram 2,94 e 2,60, o que está de acordo com os resultados por determinação química através de uma titulação ácido base.
In the present paper, the use of poly(styrene sulfonate) (PSS), produced from discarded polystyrene materials through heterogeneous and homogeneous processes, was investigated. The use of PSS for water treatment, using a kaolin suspension as wastewater model, reduced water turbidity for all the employed materials when compared to the blank analysis, without PSS. The most efficient polyelectrolyte was PSS cups obtained by homogeneous route. The same behavior was observed for real system. The homogeneous PSS cups showed a balance between a moderate molecular weight and high anionic character that improved flocks formation and water removal turbidity.