Low-temperature pyrolysis on jute fibers as a thermochemical modification method

Abstract

250, 300 o C was conducted in order to remove non-cellulosic compounds without damaging the structure of the cellulose in jute fibers. The chemical, morphological, and mechanical aspects of prepared low-temperature pyrolyzed jute fibers were investigated by Fourier transform infrared (FTIR) spectroscopy, the wettability test in water/dichloromethane system, moisture content measurement, X-ray diffraction (XRD) analysis, scanning electron microscope (SEM), and tensile test using universal testing machine (UTM). It was confirmed that hydrophilic compounds including absorbed water, low molecular weight compounds such as waxes, hemicellulose, and lignin were largely removed from the fibers. Increasing amounts of non-cellulosic compounds were removed as the maximum pyrolysis temperature was increased. The degree of hydrophilic nature of jute fibers were reduced by low-temperature pyrolysis and thus water absorptivity of pyrolyzed jute fibers was reduced as maximum pyrolysis temperature increased. Furthermore, XRD analysis and morphological studies by SEM indicated that the crystalline structure of native cellulose was rarely damaged after pyrolysis up to 300 o C. In case of mechanical properties, breaking tenacity and breaking strain of the fibers decreased with increasing maximum pyrolysis temperatures because flaws formed on the surface of pyrolyzed jute fibers acted as weak-links. In agreement with predictions made according to Weibull's weakest-link theory, it was found that shortened pyrolyzed jute fibers could have higher breaking tenacities compared with raw jute fibers of the same length. In addition, the compatibility with hydrophobic matrix was investigated by the mechanical properties of polypropylene (PP) reinforced with jute fibers. Consequently, it was hypothesized that low-temperature pyrolysis could be used to process raw jute fibers for use as short fiber reinforcements in fiber-polymer systems or be a simple and effective pretreatment method for a wide range of further chemical treatments.

Effect of Low-Temperature Pyrolysis on the Properties of Jute Fiber-Reinforced Acetylated Softwood Kraft Lignin-Based Thermoplastic Polyurethane

“…The morphological aspects showed that low-temperature pyrolysis of the jute fiber improved the interfacial bonding of the jute fiber and the ASKLTPU matrix. The removal of non-cellulosic compounds by the low-temperature pyrolysis was expected to increase the interfacial bonding between the JF and the ASKLTPU matrix, as shown in polypropylene (PP) composites with PJFs [30].…”

“…As a modification method, low-temperature pyrolysis of jute fiber was performed according to the previous work [30]. Jute fiber was put into the laboratory muffle furnace (LT3/11/P330, Nabertherm GmbH, Liliental, Germany).…”

“…The dry torrefaction or low-temperature pyrolysis was used for the conversion from bulk biomass to an energy-dense solid as fuel [29]. In the previous work, low-temperature pyrolysis of jute fibers were studied for easier thermomechanical modification method [30]. Because the decomposition of three major compounds of biomass; cellulose, hemicellulose, and lignin were distinct, the low-temperature pyrolysis up to the temperature of 200, 250, and 300 °C could be able to remove non-cellulosic compounds, such as waxes and hemicelluloses, with the least damage to the cellulose component of jute fibers [30,31,32].…”

“…In the previous work, low-temperature pyrolysis of jute fibers were studied for easier thermomechanical modification method [30]. Because the decomposition of three major compounds of biomass; cellulose, hemicellulose, and lignin were distinct, the low-temperature pyrolysis up to the temperature of 200, 250, and 300 °C could be able to remove non-cellulosic compounds, such as waxes and hemicelluloses, with the least damage to the cellulose component of jute fibers [30,31,32]. The reduction of non-cellulosic compounds decreases hydrophilicity of jute fibers and could increase interfacial bonding of jute fibers and the polymer matrix [30].…”

“…Because the decomposition of three major compounds of biomass; cellulose, hemicellulose, and lignin were distinct, the low-temperature pyrolysis up to the temperature of 200, 250, and 300 °C could be able to remove non-cellulosic compounds, such as waxes and hemicelluloses, with the least damage to the cellulose component of jute fibers [30,31,32]. The reduction of non-cellulosic compounds decreases hydrophilicity of jute fibers and could increase interfacial bonding of jute fibers and the polymer matrix [30]. Other studies on natural fibers related to heat treatments had been limited to only relatively low temperatures (i.e., 150 °C) [33] or specific purposes (i.e., studying molding conditions) [34].…”