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Identifying sustainable resources of natural fibers is essential due to their high demand in industrial applications such as automotive and biomedical materials. Two alternative fibers obtained from canola and sweet clover stalks were characterized for their properties using energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), contact angle, and tensile test. Hemp and flax fibers, both in use as industrial fibers, were also characterized as conventional fibers. Results showed that all the fibers had the same chemical elements (carbon, oxygen, magnesium, and potassium) and chemical bonds. The crystallinity index for the alternative fibers ranged from 62 to 71%, which was close but lower than the conventional fibers (82% for hemp and 80% for flax). The thermal stability of the alternative fibers was around 220 °C, close to the conventional fibers (230 °C). The alternative fibers had contact angles of less than 90°, showing high surface energy. Since the alternative fibers had a low Young's modulus and tensile strength (5.57–8.52 GPa and 57.45–71.26 MPa, respectively), they are suitable for some specific applications in the biomedical industry. In contrast, conventional fibers are suitable where a higher stiffness and strength is required. [ABSTRACT FROM AUTHOR]

Optimal treatment conditions for high quantity and quality fibers for composite applications have not been well documented for canola fibers. In this study, experiments were conducted to treat canola stalks in chemical solutions under the following treatment conditions: 12 to 72 h reaction time, 24°C to 90°C temperature, and 0% to 10% NaHCO3 concentration (% w/w). Fiber yield, chemical composition, crystallinity index, thermal stability, and maximum degradation temperature of the fibers were measured. With the experimental data, a multi-objective optimization model that was a combination of a genetic algorithm (GA) with consecutive sequential quadratic programming (SQP) was developed to predict the optimal treatment parameters. Results showed that reaction time was the most important parameter, followed by reaction temperature and NaHCO3 concentration. These treatment parameters affected the fiber yield and thermal properties in different ways. The treatments also changed the chemical composition of the fibers. The optimal treatment parameters for time, temperature, and NaHCO3 concentration to achieve the highest quantity and quality fibers were 38 h, 58°C, and 5.6%, respectively. The results from this study will enhance understanding of the relationships between canola fiber properties and treatment conditions and help in selecting the best possible treatment for extracting fibers from canola stalks. [ABSTRACT FROM AUTHOR]

There is an increasing demand for natural fibres worldwide due to their renewable and biodegradable nature. This paper reviews many aspects of natural fibres, focusing on the bast fibres of plants including hemp, flax, kenaf, jute, and ramie. Important characteristics of these plant fibres include physical, mechanical, dielectric, degradation, hygroscopic, and surface properties. These properties are highly variable, depending on both the chemical composition of the fibre and the environmental conditions. Retting and mechanical are the two main fibre extraction methods. When executed properly, retting produces the highest purity fibre; however, it is time-consuming and generates large amounts of wastewater. In contrast, mechanical extraction is faster and more environmentally friendly but results in low-purity fibre. Despite the drawbacks of bast fibres (e.g. low thermal stability, low hygroscopicity, low surface energy), they have been successfully used in insulation, composite, and geotextiles and many further applications are currently being explored. Abbreviations: AFM: Atomic force microscopy; CSA: Cross-section area; ρ: Density; DTG: Derivative thermogravimetric; γsd: Dispersive (d) component of surface free energy; γsp: Polar (p) component of surface free energy ; EMC: Equilibrium moisture content ; FACF: Fibre area correction factor; f: Fibre fineness; IGC: Inverse gas chromatography; LCA: Life cycling assessment; LLG: Limited life geotextile; LDPE: Low-density polyethylene ; MFA: Microfibril angle; RTM: Resin transfer moulding; γs: Surface free energy; WA: Thermodynamic work of adhesion; TGA: Thermogravimetric [ABSTRACT FROM AUTHOR]

Bast fibers, renewable resources used as reinforcement to develop sustainable products, are extracted from plant stalk in a process called decortication. Proper selection of critical parameters affecting decorticators' performance is required for optimization of the process. An analytical hierarchy process (AHP) was developed, according to expert feedback and experimental tests, to identify the most influential parameters affecting mechanical extraction of bast fibers. The experimental tests were done using a research-scale decorticator to find the relationship among the factors determining the quantity and quality of the fibers, and the influencing parameters. The potential inflectional parameters identified by experts were retting condition of the stalks, feed size, the number of passes through the rollers and finisher of the decorticator, 3-comb and 6-comb shaker, and stalk diameter variation. The results of the AHP model demonstrated that among seven potential parameters, the retting condition of the stalks was the most effective parameter constituting 20.4% of the total, followed by the proportion of the number of pass of stalks through the rollers (19.4%), and the feed size (18.3%). In contrast, stalk diameter variation and 3-comb shaker had the least effect on the quality and quantity of the fibers (4.4% and 10.7%, respectively). Image 1 • An analytical hierarchy process was developed to identify critical parameters affecting fibre extracton. • Experts were asked to determine the factors representing the fibers' quantity and quality. • Relationships between the parameters and the factors were examined using experiments. • The most important parameters were the 6-comb shaker, number of passes of stalks through the rollers and the finisher. [ABSTRACT FROM AUTHOR]