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Made available in DSpace on 2022-05-01T08:44:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Cellophane film production generates cellulosic residues from scraps, edges, and low-quality films. In this work, cellophane was used as a raw material to produce cellulose acetate (CA). CA was produced through the homogeneous route for 6 to 24 hours producing materials with a degree of substitution (DS) between 2.6 and 2.9. The CA materials were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and viscosity-average molecular weight. DS values (DS > 2.6) indicate the preferential formation of cellulose triacetate, and the reaction time leads to materials with different molecular weight from 32,000 to 121,000 g mol- 1 The TGA and DSC curves allowed obtaining information that, together with other techniques, confirm the formation of cellulose triacetate and the production of a material with a heterogeneous structure. The CA membrane was prepared with CA produced with 14 hours of the reaction intended to control the release rates of acetaminophen (ACP). A dense, seemingly pore-free membrane has been produced, as seen by SEM images, which allows the release of small amounts of ACP. The results were promising in the development of CA membranes for the controlled release of drugs from the chemical modification of cellophane residues. Federal Institute of Education Science and Technology of the Triangulo Mineiro (IFTM) School of Pharmaceutical Science São Paulo State University Department of Biotechnology Araraquara University (UNIARA) Pontal Institute of Exact and Natural Science Federal University of Uberlandia (UFU) Institute of Chemistry Federal University of Uberlândia (UFU) São Paulo State University (UNESP) Institute of Chemistry School of Pharmaceutical Science São Paulo State University São Paulo State University (UNESP) Institute of Chemistry

This text aims to discuss the access to education of black and indigenous populations, based on affirmative action policies, with special focus on Law 12.711 / 12. We will try to emphasize the importance of the Nucleus of Afro-Brazilian Studies - NEAB, Federal University of Uberlândia, in the process of effecting said law. In order to do so, we propose to present the history of the implementation of the "Law of Quotas" in UFU and how it is being applied in undergraduate, graduate and teacher selection processes and administrative technicians. Breaking with historical paradigms of exclusion, racism and prejudice is not a quiet process, since hegemonic forces do not want to lose their privileges and are organized to try to prevent the implementation of any policy aimed at meeting the demands of black and indigenous pollution. Pointing out challenges and pursuing strategies to overcome them is critical in this process.

EFFECT OF GLYCEROL CONTENT ON WATER VAPOR TRANSPORT THROUGH CELLULOSE TRIACETATE FILMS PRODUCED FROM THE USE OF CORN (Zea mays L.) STRAW. 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.

O presente artigo objetiva em apresentar os resultados de uma pesquisa teórica que busca investigar a (des)articulação entre a educação básica e o ensino superior, no contexto do sistema educacional brasileiro. Para tanto, é discutido neste artigo, três importantes temas que apresentam pontos fundamentais da pesquisa: o histórico das avaliações para o ingresso em Instituições de Ensino Superior (IES); o processo formativo de democratização do ensino; e, a articulação entre a educação básica e superior. Iniciamos a discussão com o vestibular no Brasil, a partir de 1911, ano em que os exames de admissão aos cursos superiores foram normatizados, e consolidamos a discussão, ao final do trabalho, com o Exame Nacional do Ensino Médio (Enem). Inferimos que a articulação entre a educação básica e o ensino superior, em muitos casos, não acontece de forma satisfatória, principalmente devido ao ensino conteudista, pragmático, memorístico e mecânico, característicos do atual sistema educacional brasileiro, especialmente nas séries finais da educação básica.

Made available in DSpace on 2018-11-26T15:29:19Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-07-01 Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) In this paper, cellulose triacetate (CTA) was produced from sugarcane bagasse and used as matrices for controlled release of paracetamol. Symmetric and asymmetric membranes were obtained by formulations of CTA/dichloromethane/drug and CTA/dichloromethane/water/drug, respectively, and they were characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Different morphologies of membranes were observed by SEM, and the incorporation of paracetamol was confirmed by lowering of the glass transition temperature (T-g) in the DSC curves. This indicates the existence of interactions between the matrix and the drug. The evaluation of drug release was based on the electrochemical monitoring of paracetamol through its oxidation at a glassy carbon electrode surface using square-wave voltammetry (SWV), which provides fast, precise and accurate in situ measurements. The studies showed a content release of 27% and 45% by the symmetric and asymmetric membranes, respectively, during 8h. Univ Fed Uberlandia, Inst Quim, BR-38400902 Uberlandia, MG, Brazil Univ Fed Uberlandia, Fac Ciencias Integradas Pontal, Ituiutaba, MG, Brazil Univ Estadual Paulista, Inst Quim, Rua Francisco Degni 55, Araraquara, SP, Brazil Univ Estadual Paulista, Inst Quim, Rua Francisco Degni 55, Araraquara, SP, Brazil FAPEMIG: CEX-APQ-01128/13

This work reports the successful use of square-wave voltammetry (SWV) to directly assess the controlled releasing profile of naproxen from lab-made cellulose derivative materials (membranes and microparticles) in phosphate buffer (pH 7.4) at 36 °C. Particular advantage of SWV refers to the direct real-time monitoring of released drug from cellulose derivative microparticles, which cannot be easily assessed by UV-spectrophotometry. Moreover, SWV was able to detect modifications in the naproxen releasing profile due to morphology and processing of membranes and microparticles. The possible miniaturization and versatility of SWV suggest the promising application on the study of several drug delivery systems, including in vivo studies.

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.

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 Agua e Esgoto - DMAE) in Uberlândia-Minas Gerais, Brazil, using Jar test experiments. Its performance was compared to ACRIPOL C10i›s, 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 C10i›s, demonstrating that the polyelectrolytes produced from recycled corn husks can replace commercial polymers in sewage treatment stations.

Made available in DSpace on 2018-11-26T15:30:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-11-05 Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Cellulose triacetate (CTA) films were produced from cellulose extracted from sugarcane bagasse. The films were characterized using scanning electron microscopy (SEM), water vapor permeability (WVP), mechanical properties (MP), enzymatic digestion (ED), and mucoadhesive properties evaluation (MPE). WVP showed that more concentrated films have higher values; asymmetric films had higher values than symmetric films. MP showed that symmetric membranes are more resistant than asymmetric ones. All films presented high mucoadhesiveness. From the WVP and MP results, a symmetric membrane with 6.5% CTA was selected for the coating of gellan gum (GG) particles incorporating ketoprofen (KET). Thermogravimetric analysis (TGA) showed that the CTA coating does not influence the thermal stability of the particles. Coated particles released 100% of the KET in 24 h, while uncoated particles released the same amount in 4 h. The results highlight the CTA potential in the development of new controlled oral delivery systems. (C) 2016 Elsevier Ltd. All rights reserved. Univ Fed Uberlandia, Inst Chem, Uberlandia, MG, Brazil Univ Fed Uberlandia, Integrated Sci Coll Pontal FACIP, Ituiutaba, MG, Brazil State Univ Paulista Julio de Mesquita Filho, Sao Paulo, Brazil State Univ Paulista Julio de Mesquita Filho, Sao Paulo, Brazil FAPEMIG: CEX-APQ-01128/13

O trabalho apresentado tem como objetivo tracar o perfil identitario dos alunos da EJA do municipio de Itumbiara (GO) mediante o levantamento das concepcoes dos sujeitos envolvidos no processo educativo – professores, coordenadores pedagogicos, diretores e alunos. Para tanto, utilizamos como instrumento de construcao questionarios especificos a cada um dos grupos de analise. Estes foram aplicados em todas as seis escolas que oferecem a modalidade EJA para o nivel de ensino medio. As analises dos resultados evidenciaram divergencias em relacao ao entendimento sobre a capacidade de aprendizado dos educandos, assim como sobre o interesse dos alunos pela disciplina de quimica. A contextualizacao dos assuntos teoricos, a disponibilizacao de material didatico e o laboratorio de ciencias, alem da formacao continuada dos professores, estao entre os principais pontos evidenciados no trabalho como limitadores a qualidade do ensino de quimica dentro da EJA.

Texto completo: acesso restrito. p. 420–426 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-08-05T12:39:01Z No. of bitstreams: 1 D. Cerqueira.pdf: 911156 bytes, checksum: 1132457170d737323a3b8d200af7af3b (MD5) Approved for entry into archive by Rodrigo Meirelles (rodrigomei@ufba.br) on 2015-10-09T18:47:38Z (GMT) No. of bitstreams: 1 D. Cerqueira.pdf: 911156 bytes, checksum: 1132457170d737323a3b8d200af7af3b (MD5) Made available in DSpace on 2015-10-09T18:47:38Z (GMT). No. of bitstreams: 1 D. Cerqueira.pdf: 911156 bytes, checksum: 1132457170d737323a3b8d200af7af3b (MD5) Previous issue date: 2012 The preparation of cellulose acetate-poly-(9,9-bis(6′-N,N,N trimethylammonium)-hexyl-fluorene phenylene) bromide (HTMA-PFP) blend films by solvent casting from a dispersion is reported. Films were characterized by UV–visible spectroscopy, SEM, electrical conductivity, TGA and DSC. It was found that morphological and physical chemical properties of blends were dependent both on the solvent and the degree of polymerization of cellulose acetate. The fluorescence properties of different blends were evaluated by fluorescence microscopy and it was shown that they are dependent on the structural properties of the blend as well as the aggregation level of the polyfluorene. Release kinetics of HTMA-PFP, incorporated into blend films, in SDS aqueous solutions have been studied and are discussed on the basis of the Korsmeyer–Peppas equation.

Texto completo: acesso restrito. p. 72–75 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-08-26T12:54:17Z No. of bitstreams: 1 Jader de Oliveira Silva.pdf: 258174 bytes, checksum: 58267e80cf77b18d796c767fe96a3645 (MD5) Approved for entry into archive by Patricia Barroso (pbarroso@ufba.br) on 2015-05-05T14:21:17Z (GMT) No. of bitstreams: 1 Jader de Oliveira Silva.pdf: 258174 bytes, checksum: 58267e80cf77b18d796c767fe96a3645 (MD5) Made available in DSpace on 2015-05-05T14:21:17Z (GMT). No. of bitstreams: 1 Jader de Oliveira Silva.pdf: 258174 bytes, checksum: 58267e80cf77b18d796c767fe96a3645 (MD5) Previous issue date: 2012 The operation of anaerobic reactors in Brazil creates a by-product, sewage sludge, for which adequate treatment is necessary to obtain a solid and stable material. The burning of sewage sludge may be an effective alternative for its management, and looking to enhance its energy potential, an environmentally friendly method of disposal is necessary. As the quantity of sludge generated has increased over the past few years, the physical chemical characterization of this waste is the first stage for its utilization as raw material. The material was characterized by thermal analyses (Thermogravimetry (TG)/Differential Thermal Analysis (DTA) and Differential Scanning Calorimetry (DSC)) and Infrared Analysis (FTIR) in order to determine the main organic groups present in sludge. The calorific power of the anaerobically digested sludge of Uberlândia-MG, Brazil was measured, and an energy content equal to 16.2 MJ kg−1 was found, which is within the range of values reported in the literature.

In this study, cellulose sulfoacetate (CSA) was produced with cellulose extracted from sugarcane bagasse with sulfuric acid as a catalyst under homogenous conditions so that the derivative could be applied as an additive for mortar of Portland (Cimento Portland de alta resistencia inicial, CPV-ARI) cement. The IR spectra showed that only precipitate C presented the characteristic band of sulfate groups (807 cm−1) and was, therefore, the sulfoacetylated derivative. CSA presented a degree of acetylation of 2.70 and a degree of sulfonation of 0.063, and the presence of sulfate groups in the derivative displaced the position of C(6) to a lower field in the 13C-NMR spectrum and influenced reduced viscosity as a function of concentration. The evaluation of CSA as an additive showed that for a polymer/cement ratio of 0.6%, an increase of 13.80% was achieved consistently, and an increase of 21.05% in the potential tensile of adhesion strength was also achieved. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Cellulose acetate is one of the components employed in drug controlled-release systems in the form of membranes. The aim of this study was to examine the controlled-release of doxycycline employing cellulose acetate symmetric and asymmetric membranes as matrices. The cellulose triacetate was produced from sugarcane bagasse through a homogeneous acetylation reaction, using acetic acid as the solvent, acetic anhydride as the acetylating agent and sulfuric acid as the catalyst. The viscosity average molecular weight of the cellulose acetate produced was 39,000 g mol −1 . The symmetric membranes were produced using a system solvent of dichloromethane/ethanol (9:1, v/v) and the asymmetric membranes were produced from the same solvent system and 10% of water. For the formulation of both, 5% of doxycycline was used. The membranes were characterized by thermal analysis (DSC and TGA) and scanning electron microscopy SEM. The release of doxycycline through cellulose triacetate matrices was examined using spectrophotometric analysis in the ultraviolet–visible region, at 275 nm. The results revealed that asymmetric membranes release 80% of the drug in 100 min, while symmetric membranes release 14% of the drug during the same time interval.

In this study, microcrystalline cellulose (MCC) was prepared from the acid hydrolysis of bacterial cellulose (BC) produced in culture medium of static Acetobacter xylinum. The MCC-BC produced an average particle size between 70 and 90 μm and a degree of polymerization (DP) of 250. The characterization of samples was performed by thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy (SEM). The MCC shows a lower thermal stability than the pristine cellulose, which was expected due to the decrease in the DP during the hydrolysis process. In addition, from X-ray diffractograms, we observed a change in the crystalline structure. The images of SEM for the BC and MCC show clear differences with modifications of BC fiber structure and production of particles with characteristics similar to commercial MCC.

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, obtained both from sugarcane bagasse and mango seeds, was used for synthesizing cellulose acetate in order to produce asymmetric membranes. These were compared to membranes of commercial cellulose acetate (Rhodia). All produced membranes were asymmetric, characterized by the presence of a dense skin and a porous support. Differences regarding the morphology of the surfaces as well as of the porous support can be noticed. Scanning Electron Microscopy (SEM) showed that the morphology of the superficial layer, responsible for transport, depends on the different lignin content of the starting material and also on the viscosity average molecular weight of the cellulose acetates produced from sugarcane bagasse, mango seed, and Rhodia’s commercial cellulose acetate.

Asymmetric membranes may be used in a broad range of applications such as reverse osmosis, hemodialysis and separation of organic mixtures. In this paper, asymmetric membranes were produced using cellulose acetate (CA) from biomass: newspaper and mango seed. The degree of substitution of CA was 2.65 ± 0.07. Different formulations were used to prepare the CA membranes: CA/dichloromethane/water with and without magnesium perchlorate. The asymmetry of the membranes was characterized by scanning electron microscopy (SEM). Membranes produced with magnesium perchlorate presented higher water vapor flux than those produced without this salt. This difference is due to pore formation in the membrane skin when using magnesium perchlorate. Membrane substructure showed to be a determining factor in ion diffusion experiments. The coefficient of ion diffusion for the membrane of cellulose acetate from mango seed was 1.82 × 10−8 cm2 s−1 while for the membrane of cellulose acetate from newspaper was 7.43 × 10−8 cm2 s−1 which similar to the value reported in the literature for commercial CA (8.46 × 10−8 cm2 s−1).

EPS Gp CCT 7137 produced by Gordonia polyisoprenivorans CCT 7137 in GYM commercial medium and sugarcane molasses alternative medium showed a carbohydrate structure composed mainly of α-anomers with presence of carboxylic and amide functional groups. The presence of carboxyl groups can be responsible for the low pH of EPS aqueous solutions, probably associated with the protein structure, acting as binding sites for cations. This characteristic is important in emulsification applications. When produced in a GYM commercial medium, EPS Gp CCT 7137 showed superior or similar emulsifying activity than commercial surfactant Triton X-100 and a better performance than EPS produced in a SM alternative medium. The results suggest the potential of EPS Gp CCT 7137 for removal of contaminating oil.

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 also showed a significant increase in electrical conductivity, with that of PANi/cellulose diacetate demonstrating an almost 200-fold increase.

Cellulose triacetate (CTA) membranes were prepared using polyethylene glycol, 600 g mol−1, (PEG) as additive and were utilized in essays of doxycycline (DOX) incorporation using two different procedures: (i) incorporation of the drug during the membrane preparation and (ii) incorporation of the drug to a previously prepared membrane. In the first, the produced membrane presented high compatibility between DOX and CTA, what was evidenced by analyzing the DSC curve for a CTA/PEG 50%/DOX system. Results showed that the drug is homogeneously distributed throughout the matrix, molecularly. In the second method, the drug was molecularly and superficially adsorbed, as seen through the DSC curve for the system CTA/PEG 10%/DOX, which nearly does not present alterations in relation to the original material, and through the isotherm of drug adsorption that follows the Langmuir model. Results showed that the membranes produced from sugarcane bagasse are adequate to produce matrices for drug-controlled release, both for enteric use (Method (i)) and topic use (Method (ii)). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Membranes of cellulose acetate from sugarcane bagasse (CA), as well as blends of this cellulose acetate and polystyrene from plastic cups (CA/PS) were produced by casting utilizing dichloromethane as solvent at the concentration 12% w/w. The membranes were characterized regarding ion diffusion by dialysis and properties of pure water permeation rate, PEG rejection (utilizing an aqueous solution 1% w/v of polyethylene glycol (PEG), 45 and 80 kDa). Thermal characterization by thermogravimetric analysis and differential scanning calorimetry were also performed. The morphology of the membranes' cross-sections was evaluated by scanning electron microscopy. The experiment of ion diffusion by dialysis showed that the ion diffusion coefficient of CA membrane is comparable to that found in the literature for membranes of commercial cellulose triacetate, 8.47 × 10−8 cm2 s−1, while the ion diffusion coefficient of blends decreased as PS was added to the system. Regarding transport driven by pressure, CA membrane presented low rejection of PEG 80 kDa. These results showed that CA membrane could be used in a range of application comprehending the process of ultrafiltration or microfiltration. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.

Cellulose acetate (CA) is one of the most important cellulose derivatives and its main applications are its use in membranes, films, fibers, plastics and filters. CAs are produced from cellulose sources such as: cotton, sugar cane bagasse, wood and others. One promissory source of cellulose is bacterial cellulose (BC). In this work, CA was produced from the homogeneous acetylation reaction of bacterial cellulose. Degree of substitution (DS) values can be controlled by the acetylation time. The characterization of CA samples showed the formation of a heterogeneous structure for CA samples submitted to a short acetylation time. A more homogeneous structure was produced for samples prepared with a long acetylation time. This fact changes the thermal behavior of the CA samples. Thermal characterization revealed that samples submitted to longer acetylation times display higher crystallinity and thermal stability than samples submitted to a short acetylation time. The observation of these characteristics is important for the production of cellulose acetate from this alternative source.

Porous polyamide membranes have been commercialized for many years and in nowadays widely used in fine separation processes often manufactured by the immersion precipitation process. This process for the membrane preparation involves precipitation of an incipient casting dope metastable. In this paper the morphology of polyamide 6,6 membranes prepared by phase inversion from ternary system (water/chloridric acid/polyamide 6,6) was investigated. Depending upon the precipitation conditions membranes the morphologics and hydraulic properties that reflect the compartment of membranes. The MP10 and MP15 membranes had been characterized in the FT-IR, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The formation of the dense layer can be observed in the scanning electronic micrographs (SEM). It can be observed that approximately 60% of the distribution of the pores were found in the band between 7 and 6nm (mesoporous system). It can be concluded that the gotten membrane is mixing, therefore presents a dense part and this membranes was a promising candidate for nanofiltration (NF) and osmosis reversal (OR) process.

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.

Cellulose Acetate (CA) produced from sugarcane bagasse cellulose was used to produce membranes, using poly(ethylene glycol) (PEG 600) as additive. Results showed that PEG 600 was washed out the membranes during the preparation step. Thermal Analysis showed that the temperature of degradation of the membranes increased in 10 °C when PEG 600 was added to the composition, but did not change as more PEG 600 was added in the composition. On the other hand, the crystalline content (%C) of the membranes increased as PEG 600 was added. The addition of PEG 600 also increased the resistance of the membranes to pressure and the pure water flux rate, but membranes produced with PEG 600 content lower than 5% did not present water flux. PEG 600 also increased the coefficient of ion diffusion of the membranes.

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.

Nanoparticles (NPs) of poly(D,L-lactic-co-glycolic acid) containing the compound 3-(benzoxazol-2-yl)-7-(N,N-diethyl amino)chromen-2-one (C2) were prepared by the solvent-evaporation technique with a mean loading efficiency of 74.0 ± 3.0%. Size distribution studies, done with dynamic light scattering and scanning electron microscopy, revealed that these particles were spherical in shape, with a mean diameter of 253 nm, a low polydispersity, and a tendency toward aggregation; the last was confirmed by the low ζ potential. A low release profile was observed for C2 when the NPs were dispersed in Hank's buffer (pH = 7.4); this was related to the low porosity of the NPs and the extremely low diffusivity of C2 in water. Differential scanning calorimetry data presented a glass-transition temperature depression caused by an increase in the NP molecular mobility after the incorporation of C2. Spectroscopic and photophysical data exploring the capabilities of C2 as a fluorescent probe suggested a high microviscosity for the environment in which the probe was allocated, which was most likely due to strong polar interactions involving ester groups from the polymer and the diethylamino moiety from C2. The cellular toxicity and uptake of C2 and NP–C2 systems were evaluated with B16-F10 murine cells, which showed that C2 (in solution or encapsulated) was nontoxic and able to be located inside the neoplasic cells. Besides, the encapsulation method was capable of maintaining the drug's properties and improved the drug delivery to the target cell. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

In the present paper, methylcellulose was produced from cellulose extracted of sugar cane bagasse, using dimethyl sulfate in heterogeneous conditions. The infrared spectra of the cellulose and of the methylcellulose present significant differences at the regions from 3600 to 2700 cm−1 and from 1500 to 800 cm−1. The ratio between the absorption intensities of the O H stretching band (∼3400 cm−1) and the C H stretching band (∼2900 cm−1) in the spectra of the methylated samples is lower than that in the cellulose spectrum, evidencing the methylation of the samples. The effect of using toluene and acetone during the synthesis was studied. Without using the solvent, the degree of substitution (DS) of the methylated sample was 0.70, reaching a DS of 1.2 when using acetone. The produced methylcellulose presents chemical and physical properties that increase its range of application and aggregate value to this agro-industrial residue.

In this article, the compatibility of blends produced from recycled materials—cellulose acetate (from sugarcane bagasse) and polystyrene (from plastic cups)—was studied using diffusion of water, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. With these techniques, it was possible to confirm the existence of miscibility microregions in blends produced according to what has already been pointed out in a previous paper (Filho et al., J Appl Polym Sci 2005, 96, 516). In addition, all the results present a transition occurring in blends containing 30% polystyrene. This composition indicates the starting limit for a possible inversion between the matrix and the disperse phase in the system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 909–914, 2007

Made available in DSpace on 2018-12-11T17:25:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-09-01. Added 1 bitstream(s) on 2021-07-15T15:03:47Z : No. of bitstreams: 1 S0103-50532015000901861.pdf: 835839 bytes, checksum: ff2a35b139836a0848c2a81a36398f7f (MD5) In 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 diffraction (XRD), differential thermal analysis (DTA), thermal gravimetric analysis (TGA), 13C nuclear magnetic ressonance (NMR) and 1H NMR techniques. The FTIR spectra of the BC and MC samples present significant differences in the regions from 3750 to 2750 cm-1 and from 1500 to 750 cm-1, which evidence the methylation of the samples. Solid state NMR spectroscopy of the MC samples was used to identify the 13C NMR signals of substitution at sites C-2, C-3 or C-6 in the glucopyranose units. The modification of bacterial cellulose produced a material with a high DS, determined by three different techniques (chemically and using the liquid 1H and solid 13C NMR spectra). These samples also demonstrate high crystallinity and thermal stability. With the MC samples synthesized in this work, transparent and resistant films were prepared and also a highly porous sponge like material. Instituto de Química, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP) Instituto de Química, Universidade Federal de Uberlândia Faculdade de Ciências Integradas, Universidade Federal de Uberlândia Instituto de Química, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)

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.