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The use of lignocellulosic fibers derived from renewable resources as a reinforcing phase in polymeric matrix composites provides positive environmental benefits with respect to ultimate disposability and raw material use. Despite the attractive properties, lignocellulosic fillers are used only to a limited extent in industrial practice due to the restriction to 200°C in composites processing temperatures. Lignocellulosic materials start to degrade near 230°C. This limits the type of thermoplastics that can be used in association with polysaccharide fillers. To overcome these disadvantages, chemical treatments, i.e. alkaline treatment, were applied to curauá fibers to improve the thermal properties. Colorimetry was employed to evaluate the extension of darkening of composites prepared with treated curaua and Avicel. Fourier-transform infrared spectra of polyamide composites with treated curaua showed no differences when compared to pure polyamide. Moreover, no changes in molar mass were observed in microcrystalline cellulose processed in different temperatures. [ABSTRACT FROM AUTHOR]

This work aims to prepare composites of polyamide 66 with vegetal fibers from curauá, jute, and flax. Alkaline treatment was conducted followed by silanization, improving the thermal properties of treated natural fibers. To reduce the processing temperature of polyamide 66, a combination of LiCl andN-butylbenzenesulfonamide was added to pure polyamide 66. It is shown that plasticizing polyamide 66 is one way to prepare composites with natural fibers using this high temperature polymer. The increase in elastic modulus of polyamide 66 and the decrease in strain at break were observed. [ABSTRACT FROM AUTHOR]