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This work investigated the effect of thermal treatment in an autoclave on the chemical, physical, and morphological properties of lignocellulosic fibers from açaí (Euterpe oleracea Mart), and the behavior of this treated fiber in polypropylene (PP) matrix composites with polypropylene-graft-maleic anhydride (PPgMA) as the coupling agent. The treated and untreated fibers were characterized by chemical composition, x-ray diffraction, FTIR spectroscopy, and thermogravimetry, scanning electron microscopy and tensile tests were carried out for the composites. The results showed that the thermal treatment modified the hemicellulose and lignin content and increased the fiber surface roughness, without compromising the thermal stability. The composite prepared with thermally treated fibers and PPgMA exhibited an increase in tensile strength but a reduction in tensile modulus. In conclusion, the thermal treatment of vegetable fiber is a promising technique for improving the performance of composites.

Buriti (Mauritia flexuosa) is a palm tree widely distributed in South America. The oil extracted from its fruit is an added value product for its high carotenoids content. The aim of this work was to evaluate the alkaline (magnesium oxide-MgO) and enzymatic (lipase B from Candida antarctica immobilized on macroporous acrylic resin) glycerolysis of buriti oil to obtain non-ionic emulsifiers and evaluate the carotenoids degradation during this process. Alkaline glycerolysis was carried out using a 3:1 glycerol/oil molar ratio, temperatures of 170 and 210 C, and MgO contents of 0.5 and 1%wt. Enzymatic glycerolysis reactions were performed using 3%wt. of a lipase catalyst and varying the following parameters: glycerol: oil molar ratio (3:1, 6:1, and 9:1), solvent (tert-butyl alcohol) concentration (50%, 150%, and 250%, vol./substrate mass), and temperature (40, 55 and 70 C). The products were analyzed by liquid chromatography and UV-visible spectroscopy (370-520 nm). Enzymatic glycerolysis was superior in terms of conversion and selectivity to monoacylglycerols (MAG). MAG yields were close to 80% or higher for most conditions tested for enzymatic glycerolysis, while the maximum yield for alkaline glycerolysis was of 58%. UV-Vis data showed that carotenoids were severally degraded in alkaline glycerolysis, while the enzymatic product exhibited high preservation of carotenoids and color and odor similar to those of the pure buriti oil. Based on the final composition of the non-ionic emulsifiers obtained from buriti oil by enzymatic glycerolysis, they can be considered potential raw materials for cosmetic and food industries.

In this work, a bio-based adhesive is prepared from Protium heptaphyllum resin. The resin is first characterized by 1 H and 13 C nuclear magnetic resonance spectroscopy and the bioadhesive is then prepared using a simple mixture of the resin with linseed oil, catalyzed by cobalt octanoate, to induce crosslinking. The precursors and bioadhesive obtained are characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The NMR analysis shows the presence of groups of triterpenes, such as α-and β-amyrins, and diols, such as brein and maniladiol. Thermogravimetric analysis reveals that the resin has less thermal stability than the bioadhesive. Mechanical tests indicate that the bioadhesive has greater adhesion strength compared to the commercial adhesive, reaching an average stress at break of 7.66 and 0.113 MPa for the wood and carbon steel substrates, respectively. In conclusion, the bioadhesive can be used for the production of composites.