In this work, the relationship between cellulose crystallinity, the influence of extractive content on lignocellulosic fiber degradation, the correlation between chemical composition and the physical properties of ten types of natural fibers were investigated by FTIR spectroscopy, X-ray diffraction and thermogravimetry techniques. The results showed that higher extractive contents associated with lower crystallinity and lower cellulose crystallite size can accelerate the degradation process and reduce the thermal stability of the lignocellulosic fibers studied. On the other hand, the thermal decomposition of natural fibers is shifted to higher temperatures with increasing the cellulose crystallinity and crystallite size. These results indicated that the cellulose crystallite size affects the thermal degradation temperature of natural fibers. This study showed that through the methods used, previous information about the structure and properties of lignocellulosic fibers can be obtained before use in composite formulations.

Textiles have been used in our daily life since antiquity in both economies and social relationships. Nowadays, there has never been a greater desire for intelligent materials. Smart fabric textiles with high-quality and high-performance fiber manufacturing with specific functions represented by clothing and apparel brands (such as astronaut suits that can regulate temperature and control muscle vibrations) are becoming increasingly prominent. Product applications also extend from the field of life clothing to the medical/health, ecology/environmental protection, and military/aerospace fields. In this context, this review proposes to demonstrate the recent advances and challenges regarding smart fabric textiles. The possibilities of innovative smart textiles extending the overall usefulness and functionalities of standard fabrics are immense in the fields of medical devices, fashion, entertainment, and defense, considering sufficient comfort as a parameter necessary for users to accept wearable devices. Smart textile devices require a multidisciplinary approach regarding the circuit design of the development of intelligent textiles, as the knowledge of intelligent materials, microelectronics, and chemistry are integrated with a deep understanding of textile production for optimum results.

This study aims to evaluate the influence of fiber hybridization and frequency on the dynamic mechanical properties of ramie/glass hybrid fiber-reinforced polyester composites. The storage modulus ( E′), loss modulus ( E″) and damping behavior (tan δ) were evaluated as a function of different relative glass/ramie fiber volume ratios. For the storage modulus, the importance of the reinforcement effect above T_g was revealed. Also, the peak height, peak width at half-height and relaxation area were investigated for the loss modulus and tan δ curves, showing the influence of a shoulder below T_g for each case. Finally, the tan δ peak shifts to higher temperatures by increasing the frequency. Higher activation energy was observed for 75% glass fiber-containing composites.