This study show influence of alkaline treatment on sisal fiber (SF) in different composites of starch matrices (SM) and cellulose acetate matrices (CAM). SF were modified with an aqueous 0.5M NaOH solution. Composites were prepared in proportion of 3% fiber/matrix (m/m) using casting method. The samples were characterized by Scanning Electron Microscopy (SEM), Fourier-Transform Infrared Spectroscopy by Attenuated Total Reflection (FTIR-ATR), Thermogravimetric Analysis (TGA) and Dynamic-mechanical thermal analysis (DMA). Through results obtained in FTIR and TGA, it was possible to verify that alkaline treatment partially removed hemicellulose and SF lignin. With SEM, best fiber/matrix adhesion in composites prepared with modified fiber (TSF) has been proven to change fibre morphology. Through DMA analysis it was possible to observe that after addition of SF and TSF, SM composites showed improvements in mechanical properties, while TGA showed an increase in initial temperature of thermal degradation in CAM composites with addition of fiber.

The lignin present in the vegetal tissues of the sugarcane bagasse is an interesting material due to its aromatic characteristics. Particularly in Brazil, studies involving the extraction of lignin from sugarcane bagasse have been widely researched due to the high volume of bagasse generated in our country. Recent studies have shown that after isolation, lignin is a raw material that can be used as a pesticide, solution stabilizer and particularly for the production of phenolic resin partially replacing phenol. The present study aimed to isolate and characterize the lignin present in sugarcane bagasse by the acetosolv pulping method. The sugarcane bagasse was pre-treated to remove organic and hot water-soluble extracts, and then acetic (solvent) and hydrochloric (catalyst) acids and water at the temperature were used. boiling point for the isolation of lignin by the acetossolve process. The obtained lignin was characterized by chemical performance analysis, Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC) and thermogravimetry (TGA). The extraction yield of lignin acetosolv was 19.95 % under total sugarcane bagasse. In the lignin FTIR spectrum the stretch range between 1594 and 1511 cm-1 confirm the preservation of the aromatic structure. GPC analysis demonstrated a low polydispersity of lignin acetosolv. TGA analysis showed no residues above 600°C, indicating high content of organic material, confirming the purity of the extracted sample. It is concluded, therefore, that the acetossolve pulping method for lignin extraction may be an efficient alternative, in view of the processes traditionally employed if fibers, not wood (sugarcane bagasse) are used. The fact that it is a process that does not use pressure combined with the possibility of recovering inputs by simple evaporation, makes the acetosolv competitive and with less environmental damage than other traditional processes. A lignina presente nos tecidos vegetais do bagaço da cana é um material interessante devido às suas características aromáticas. Particularmente no Brasil, estudos envolvendo a extração de lignina do bagaço de cana têm sido amplamente pesquisados devido ao alto volume de bagaço gerado em nosso país. Estudos recentes demonstraram que, após o isolamento, a lignina é uma matéria-prima que pode ser usada como pesticida, estabilizador de solução e particularmente para a produção de resina fenólica, substituindo parcialmente o fenol. O presente estudo teve como objetivo isolar e caracterizar a lignina presente no bagaço de cana-de-açúcar pelo método de polpação acetossolve. O bagaço de cana-de-açúcar foi submetido a um pré-tratamento para a remoção de extrativos orgânicos e extrativos solúveis em água quente, e posteriormente, utilizaram-se os ácidos acético (solvente) e clorídrico (catalisador), e água na temperatura de ebulição, para o isolamento da lignina, pelo processo acetossolve. A lignina obtida foi caracterizada por análise química de rendimento, espectroscopia na região do infravermelho com transforma...

Currently, non-biodegradable polymers are produced on a large scale and cause several environmental problems, especially due to their low degradation. Cellulose acetate is a non-toxic, low-flammable and low-cost polymer, playing an important environmental role. The objective of this study was to synthesize cellulose acetate membranes from Schizolobium parahyba wood (“guapuruvu”) with particles sizes of 20 and 60 mesh. The materials were submitted to acetosolv pulping, bleaching and acetylation to produce the acetates. The yields and the degree of substitution were found. The fibers were chemically characterized and the samples obtained at each processing step were analyzed by FTIR. It was possible to prepare acetates from both granulometries wood. The FTIR analysis showed changes on the samples’ bands, indicating that the chemical processes were efficient. Cellulose acetate obtained from the 60 mesh material presented a higher degree of substitution (2.74 ± 0.12) when compared to the 20 mesh acetate (2.59 ± 0.13), showing that the particle size of the material influenced on the efficiency of the acetylation reaction. DMA tests have demonstrated that the 60 mesh membrane has higher flexibility and transparency when compared to the 20 mesh membrane.