Effect of chemical treatment on the thermal properties of hybrid natural fiber‐reinforced composites

ABSTRACT The main objective of this work is to study the effect of chemical treatment on the thermal properties of hybrid natural fiber‐reinforced composites (NFRCs). Different chemical treatments [i.e., alkalized and mixed (alkalized+ silanized)] were used to improve the adhesion between the natural fibers (jute, ramie, sisal, and curauá) and the polymer matrix. A differential scanning calorimetry, thermogravimetry, and a dynamic mechanical analysis were performed to study the thermal properties of hybrid NFRC. It was found that the chemical treatments increased the thermal stability of the composites. Scanning electron microscopy images showed that the chemical treatments altered the morphology of the natural fibers. A rougher surface was observed in case of alkali treated fiber, whereas a thin coating layer was formed on the fiber surface during the mixed treatment. However, for some fibers (i.e., sisal and rami), the chemical treatment has a positive impact on the composite properties, whereas for the jute and curauá composites, the best behavior was found for untreated fibers. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47154. In this study, jute, jute + ramie, jute + sisal and jute + curauá hybrid fabrics were modified by the alkaline and mixed (NaOH + silane) treatments. A differential scanning calorimetry (DSC), thermogravimetry (TG) and a dynamic mechanical analysis (DMA) were performed to study the thermal properties of hybrid natural fiber reinforced composites as a function of treatment. It was found that the chemical treatments increased the thermal stability of the composites. The figure below shows the chemical effect on the jute + sisal composite indicating the changes in its morphological structure caused by each treatment.