Ramie Fiber Research Articles

Properties of Ramie (Boehmeria nivea (L.) Gaudich) Fibers Impregnated with Non-Isocyanate Polyurethane Resins Derived from Lignin.

The textile industries need an alternative to cotton since its supply is unable to keep up with the growing global demand. The ramie (Boehmeria nivea (L.) Gaudich) fiber has a lot of potential as a renewable raw material but has low fire-resistance, which should be improved. In this work, the objectives were to investigate the characteristics of lignin derived from black liquor of kraft pulping, as well as the properties of the developed lignin-based non-isocyanate-polyurethane (L-NIPU), and to analyze ramie fiber before and after impregnation with L-NIPU. Two different formulations of L-NIPU were impregnated into ramie fiber for 30, 60, and 90 min at 25 × 2 °C under 50 kPa. The calculation of the Weight Percent Gain (WPG), Fourier Transform Infrared Spectrometer (FTIR), Rotational Rheometer, Dynamic Mechanical Analyzer (DMA), Pyrolysis Gas Chromatography Mass Spectrometer (Py-GCMS), Universal Testing Machine (UTM), and hydrolysis test were used to evaluate the properties of ramie fibers. The result showed that ramie fiber impregnated with L-NIPU produced higher mechanical property values and WPG than non-impregnated ramie fiber. There is a tendency that the longer impregnation time results in better WPG values, FTIR intensity of the urethane group, thermomechanical properties, crystallinity, and mechanical properties of ramie fiber. However, the use of DMC and HMT cannot replace the role of isocyanates in the synthesis of L-NIPU because it produces lower heat resistance than ramie impregnated using pMDI. Based on the results obtained, the impregnation of ramie fiber with L-NIPU represents a promising approach to increase its wider industrial application as a functional material.

Comparative biochemical and transcriptomic analysis reveals the phosphate-starving tolerance of two ramie varieties

Ramie (Boehmeria nivea L.) is a highly valued fiber crop. Its yield is often limited by lack of available phosphate (Pi) in the soil, but the underlying molecular mechanisms of ramie's response to Pi deficiency remain largely unknown. To investigate how ramie adapts to low Pi stress, we selected a low Pi-tolerant variety (H-5) and a low Pi-sensitive variety (XYL), and conducted a biochemical and transcriptomic analysis on roots and leaves of both varieties. After subjecting the plants to Pi-deficient and Pi-sufficient conditions for 15 days, we found that H-5 exhibited higher dry weight, longer root systems, and higher levels of Pi, galactolipids, and organic acids when subjected to Pi deprivation, compared to XYL. Transcriptomic analysis further revealed that Pi-responsive genes involved in lipid metabolism, Pi transport, organic acid synthesis, and acid phosphatase activities were more induced in the tolerant variety H-5. Furthermore, weighted gene co-expression network analysis (WGCNA) identified five hub genes, including phosphate transporter, SPX domain-containing protein and sulfoquinovosyl transferase, which played key roles in low Pi tolerance in ramie. The present study will broaden our comprehension of the differences and molecular mechanisms of different ramie cultivars in response to Pi starvation, and lay a foundation for future agronomic improvements in ramie and other fiber crops.

Exploring the Potential of Ramie Fiber Composites as Eco-friendly Materials for Medical Prostheses

The insect Callosobruchus maculatus, is responsible for serious damages in the storage of grains of diverse cultures, among them, the one of the beans. Therefore the development of substances capable of being an alternative to minimize agricultural losses and thus contribute to food security of the population is a current necessity.This research aims to explore new materials derived from natural fibers for the development of environmentally friendly and recyclable medical devices, particularly prostheses. The focus is on utilizing ramie fiber, a natural fiber, as a substitute for artificial fibers and plastics in composite materials. The study investigates the impact and bending strength of ramie fiber composites by varying the volume fraction and fiber orientation. The experimental design involves three volume fractions (1%, 3%, and 5%) and three fiber orientations (10°, 20°, and 30°). Hand lay-up method is employed on molds, ASTM D256 impact tests and ASTM D7264 bending tests are conducted to assess the mechanical properties. The findings indicate that the ramie fiber composite with a volume fraction of 5% and fiber orientation of 30° exhibits the highest bending strength, measuring 471.1 Mpa. Similarly, this composition demonstrates the highest impact strength value of 26,558,720 Pa. Overall, this research contributes to the advancement of sustainable materials for medical prostheses and highlights the significance of optimizing the composition of ramie fiber composites to enhance their mechanical properties.
 Keywords: Ramie Fiber, Composite Materials, Medical Prostheses

Effect of Hybridization of Ramie Fibers on the Vibrational and Damping Responses of Ramie/Glass/Epoxy Resin Composite Laminates

Fiber reinforced polymer composites made with glass fibers are among the oldest and most popular kinds of composites in use today. Glass fiber reinforced composites' key benefits are their adaptability for specific material applications, which allows them to give a number of design advantages relating to strength, chemical stability, impact damage tolerance, heat insulation, and low cost. The focus of this research is to investigate the role of hybridized ramie fibers in the assessment of enhanced vibrational damping capabilities in fiber glass reinforced composites, as well as in the initial assessment to verify their acceptability for real-time applications. Composite molding employing the hand layup technique was used to fabricate hybrid epoxy composites with ramie to glass fiber weight ratios from 0 to 50%. A free vibration test was performed to determine the hybrid composite's vibration dampening capabilities as a function of the ramie fiber filler content. The results demonstrated that the damping ratio was reduced when the percentage of ramie fiber in the GFRP composite was raised from 10% weight to about 50% weight. But adding up to 40% wt of ramie fiber to the hybrid composite had the biggest effect on the damping ratio, natural frequency, storage modulus, and loss modulus. This means that using ramie fiber in hybrid composites will be cost-effective and good for the environment.

Improving mechanical properties of laminated biocomposites for artificial lower limb socket

People need artificial limbs for many reasons, such as illness, injury, or a gene problem. However, these limbs must be changed often because the human body changes as it gains or loses weight. This study examines whether plant fibers could be used instead of metal to make sockets for lower limb prosthetics using a vacuum bagging process. The laminates were formed using woven ramie fiber, bamboo fiber, carbon fiber, glass fiber, Kevlar fiber, and ultra-high molecular weight polyethylene UHMWPE fiber. Several mechanical tests, such as impact, maximum shear stress, and flexural tests, were done to investigate the effect of different ways of stacking the fibers on certain mechanical and physical properties. The goal was to find out how changing the orientation and distribution of the fibers affected the composite's properties and how it worked. The outcomes of the tests were evaluated and analyzed to identify the optimal stacking pattern that would yield the desired properties for the composite material. The present investigation demonstrated that the incorporation of diverse reinforcing agents into composite materials exerted a significant influence on their mechanical strength. The composite's properties, such as flexibility, stress tolerance, and toughness upon fracture, improved proportionally with the increasing addition of these materials. The sample with the lamination of (2 perlon + 2 ramie + 2 carbon + 2 ramie + 2 perlon) fiber layers has shown a good impact strength of 81 KJ/m2, a maximum shear stress of 6.07 MPa, and a fracture strength of 174.1 MPa. Novel findings regarding the effect of altering the orientation and distribution of these fibers on the composite's properties could develop more effective prosthetic materials.

Improvement Mechanical Properties of Epoxy Composite Reinforced with Sisal, Ramie and Carbon Fibers

In this paper, justification of mechanical characteristics is carried out to determine the ability of bio-composites to become structural composite bicycle frames capable of achieving strengths of more than 300 [MPa]. Sisal fiber is a natural fiber that is widely used as a composite fiber and is easy to cultivate. The fiber is believed to originate from Central and South America. Nearly 4.5 million tons of sisal fiber are produced annually worldwide, according to FAO. In building structural materials, in addition to structural strength, it is hoped that the material will also have good ductility. For this reason, the assembled bio-composite material consists of carbon fiber, ramie fiber, sisal fiber. The fiber is then mixed with hard epoxy resin, soft epoxy and aluminum particles 9 µm which are mixed until smooth and even. The significant increase in material strength is obtained from the strength of carbon fiber. Another thing is that the ductility of the material is obtained due to sisal and ramie which are bound by a mixture of epoxy resins. Because the quality of plant products is very dependent on the agricultural process, this study, the residual material was taken from the Subang (Indonesie) area and the ramie fiber was obtained from the Bandung market. Because agricultural cultivation in Indonesia still emphasizes the use of chemicals, basically this also has an impact on plant bio elements. However, research using local materials was still able to obtain strength reaching ~480 MPa, so it is still good. In this research, the tensile test was carried out 3 times so that it is known that the fiber taken from a rope has the greatest tensile strength which reaches around 480 MPa.

EFFECT OF ADDITION RAMIE AND COCONUT COIR FIBERS WITH DIFFERENT CONCENTRATIONS ON TENSILE STRENGTH OF ACRYLIC DENTURE BASE

Background: Acrylic denture base material has advantages such as good aesthetics, ease of repair, and affordable price, but this denture has mechanical properties, one of which is low tensile strength so fractures often occur during use. Utilization of natural fibers such as ramie (Boehmeria Nivea) and coconut coir (Coco Nucifera L) can be used as an alternative reinforcement for acrylic denture bases. Purpose: To determine the effect of adding ramie fiber and coconut coir fiber at different concentrations on the tensile strength of the acrylic denture base. Method: This study used a laboratory experimental method with a flat dumbell-shaped specimen with a size of 75 × 10 × 3 mm based on ISO 527-1 (2019). The specimens consisted of 42 plates which were divided into 7 groups, namely 6 specimens each group without fiber addition (control), with the addition of ramie fiber 1%, 2%, 3%, and the addition of coconut coir fiber 1%, 2%, 3%. Tensile strength testing using Universal Testing Machine (UTM), data were analyzed by One-way ANOVA test and Post Hoc LSD test. Result: The 3% ramie fiber addition group had the highest tensile strength (76.47 MPa), the 1% coconut coir fiber addition group had the lowest tensile strength (58.91 MPa). There was a significant difference in the results of the control group's tensile strength test and the addition of 3% ramie fiber and 1% coconut coir fiber (p-value < 0.05). Conclusion: The greater the concentration of ramie and coconut fiber additions, the higher the tensile strength value, although the tensile strength value in the coconut fiber addition group was lower than the control group and ramie fiber addition.

Development and characterization of titanium oxide filled ramie fiber based hybrid composites

AbstractThis investigation aims to develop and characterize a class of multi‐phase hybrid composites consisting of bi‐directional ramie fibers, epoxy resin and micro‐sized titania (TiO2) particles in different proportions. Conventional hand layup technique is followed for fabrication of these composite slabs with fixed fiber fraction but different filler loadings of 0, 10, 20, and 30 wt%. The composites are subjected to different physical, compositional, and mechanical characterization tests under controlled laboratory conditions. The microstructural features of the composites are studied using scanning electron microscopy and stereo‐microscopy. For the compositional analysis, Fourier transform‐infrared spectroscopy (FTIR) and X‐ray diffraction (XRD) technique are adopted. The functional groups present in the constituent materials are identified and so also the different phases in the composites. The different characterization tests reveal that with the incorporation of hard titania particles, the tensile, flexural, inter‐laminar shear strength, hardness, and impact strength improve. Similarly, the density and moisture absorption behavior are also found to be greatly affected by the inclusion of fillers. Armed with reasonably good mechanical properties and improved hardness, these epoxy‐ramie composites filled with titania micro‐particles may possibly find applications as functional materials in potential areas like wear prone situations.Highlights Hybridization of ramie‐epoxy composite by additional reinforcement of TiO2. Physical properties of the composites are affected by the inclusion of fillers. Mechanical properties of composites improved with filler content. The developed composites can be used for wear resistant applications.

Physical and Mechanical Behavior of Ramie and Glass Fiber Reinforced Epoxy Resin-Based Hybrid Composites

ABSTRACT In this study, the compression molding technique was used to fabricate hybrid composites using different wt.% of the glass and ramie fibers in different stacking sequences. The physical (density, water absorption, and wear resistance) and mechanical (tensile strength, hardness, and impact strength) and morphology studies were performed for the glass and ramie fibers and the effect of stacking sequencing was studied. A technique for order of preference by similarity to the ideal solution model was used to determine the optimal reinforcement composition in the hybrid composites. The stacking sequence played a crucial role in the physical and mechanical characteristics of the hybrid composites. The GRG (stacking sequence: Glass (4 wt.%)-Ramie (4 wt.%)-Glass(4 wt.%)) hybrid composite showed optimal characteristics; tensile strength: 114 MPa, hardness: 41 HV, impact energy: 3.5 J m−1, void content: 1.09% and wear: 63 μm. However, if glass fibers were sandwiched between the ramie fiber layer, the composite showed lower physical and mechanical characteristics; tensile strength: 72 MPa, hardness: 28 HV, impact energy: 3 J m−1. The glass fiber reinforced composites (GG and GGG) exhibited better water absorption characteristics. The RRR composite’s impact strength was comparable with the GGG composites due to the stacking of the composites. Moreover, the glass fiber composites stacking (RR to RGR) exhibited lower tensile strength than ramie fiber composites stacking (GG to GRG). The microstructural analysis of the fractured composite surface revealed voids, de-lamination, interfacial bonding of the fibers with the matrix, fiber pull-out, and matrix distribution.

The influence of residual pectin composition and content on nanocellulose films from ramie fibers: Micro-nano structure and physical properties

In this study, cellulose nanofibril (CNF) films from ramie fibers were prepared with different pectin compositions and contents, and the influence of residual pectin on the overall performances of CNF films was evaluated. There was no significant effect of the residual pectin composition on the properties of obtained CNF films. However, when the content of residual pectin was increased from 0.45 % to 9.16 %, the surface area and water absorption of CNF films were increased from 0.2223 to 0.3300 m2/g, and from 93.51 % to 122.42 %, respectively. Pectin covers the CNF surface and act as a physical barrier between the cellulose fibrils; thus the nanocellulose films with high pectin content will have a loose and porous structure, resulting in a high surface area and a high water absorption. Besides, with the residual pectin content decreasing from 9.16 % to 0.45 %, the UVA light transmittance and tensile strength of CNF films were increased from 30.6 % to 59.9 %, and from 37.67 to 100.26 MPa, respectively. After removal of amorphous pectins in CNFs, the low pectin containing CNFs are able to pack more compactly to form a strong and thin film. This paper provides guidance for the preparation of CNF films with different performance requirements.

Erosion wear response of ramie‐epoxy composites using artificial neural network integrated with Taguchi technique

AbstractThis paper aims on evaluating the erosion wear behavior of epoxy composites reinforced with ramie fibers. The possibility of reinforcing ramie fiber to improvise the wear resistance of epoxy is investigated in this study. Composites are fabricated by reinforcing multiple layers of woven ramie fiber mats into epoxy resin using conventional wet lay‐up technique and erosion wear trials are conducted using solid particle erosion test setup. Taguchi analysis is done to assess the relative significance of each of the factors influencing the erosion rate using L16 orthogonal array. The analysis reveals that the impact velocity followed by impingement angle are the most significant control factors affecting the erosion wear rate of ramie‐epoxy composites. Steady state erosion analysis is done to ascertain the effect of each of the significant factors while keeping other factors fixed. Further, an analytical and predictive model based on the principle of neural computation is used to predict the rate of erosion wear of the composites and the obtained results are compared with the experimental outcomes. The worn morphologies of the eroded surfaces of the composites are studied and analyzed to identify possible mechanisms causing wear.

Standardization of Chemical Degumming and Biodegumming of Ramie Fiber Processing for Natural Fiber Supply Chain Strategy as A Source of Textile Raw Materials in Indonesia

Ramie’s natural fiber industry (Boehmeria nivea) has the potential to be able to supply natural cellulose raw materials to meet the demands of the textile industry. A potential consideration in manufacturing ramie-based products is the need for an integrated set of processes to operate efficiently along the supply chain. A strategy in maintaining the supply chain in manufacturing ramie fiber is based on standardization of the upstream production process starting from the ramie cultivation system and processing raw fiber resulting from the decortication process. Raw fiber is processed by standardized procedures, either chemical degumming or biodegumming, using enzymatic activity produced from microorganisms such as bacteria and fungi. The purpose of this research is to provide a standardized production line for the manufacture of ramie raw fiber. The study reports on a number of issues, including: supply of ramie fiber, degumming process include biological dan chemical degumming methods which has been used as a production process for small-scale industrial in Indonesia. The recommendation must be tested with data from manufacturing companies in the ramie industry to develop it as a standardized ramie industrial product model in Indonesia.

Tensile Strength Improvements of Ramie Fiber Threads through Combination of Citric Acid and Sodium Hypophosphite Cross-Linking

Ramie (Boehmeria nivea) is believed to be one of the strongest natural fibers, but it still remains behind synthetic materials in terms of tensile strength. In this study, ramie materials were prepared to evaluate the modification crosslinking effect of natural fiber. The aim is to optimize various concentrations of citric acid (CA) crosslinking by adding Sodium hypophosphite (NaPO2H2), which is activated at different temperatures, to obtain the highest tensile mechanical strength. This crosslinking effect has been confirmed by FTIR to show the esterification process in the molecular structure of cellulose. The changes in the character of the fiber surface were analyzed by SEM. The tensile strength increased from 62.33 MPa for 0% CA to 124–172.86 MPa for decorticated fiber with a CA concentration of 0.75–1.875% (w/w). A significant increase in tensile strength was observed more than 19 times when CA/SHP 1% was treated at an activation temperature of 110 °C with a superior tensile strength of 1290.63. The fiber crosslinked with CA/SHP should be recommended for application of Natural Fiber Reinforced Polymer Composite (NFRPC), which has the potential to use in functional textile and industrial sector automotive or construction.

A novel 3D printed continuous ramie fiber reinforced variable stiffness biocomposite honeycomb structure

In this paper, a novel 3D printed continuous ramie fiber reinforced variable stiffness biocomposite honeycomb cellular structure (CF-VSHS) was reported. Based on the printing path planning of CF-VSHSs, variable stiffness (VS) cellular structures filled with cells of various dimensions were prepared by employing a detachable and recyclable support-assisted printing method. In order to evaluate the mechanical performances of CF-VSHSs, compressive tests were conducted. The results showed that CF-VSHSs effectively filled the performance gap area of the cellular structures. The energy absorption (EA), initial peak force (IPF), stiffness (S), and other performance indicators of CF-VSHSs were all located between the performance of different cellular structures. In addition, 3D printed CF-VSHSs were analyzed regarding failure processes and damage features to reveal their structure-compressive performance relationship.

Study on water absorption of hydrophobically modified ramie fiber and the reinforced polypropylene composites

AbstractTo study the effects of fiber surface hydrophobicity on water absorption of composites, ramie fiber was hydrophobically modified with polydopamine/octadecylamine and then used to reinforce polypropylene. The fiber modification was characterized by infrared spectroscopy, scanning electron microscopy, energy spectrometry, contact angle, and water absorption. The mechanical properties and water absorption of the composites were also characterized. The results indicated that polydopamine/octadecylamine was successfully grafted onto the fiber surface. With the increase of octadecylamine concentration, the fiber surface became more and more hydrophobic, and its contact angle achieved a maximum of 118 ± 2.97° when octadecylamine concentration was 8 g/L. However, the modified fiber remained a high level of saturated water absorption of 6.53% ± 0.09%. For composites, when the octadecylamine concentration was 0.5 g/L, its water absorption showed the lowest value of 1.81% ± 0.09%. With more octadecylamine was grafted onto the fiber, the water absorption did not decrease continuously but showed a small growth peak. It is concluded that water absorption of composites is greatly affected by water absorption of fiber. The surface hydrophobic modification on fiber is beneficial to improve its surface hydrophobicity and inhibit the interfacial water absorption between fiber and matrix. However, it fails to the improve internal hydrophobicity of the fiber, nor does it inhibit the fiber in composites from absorbing water.

Bnt05G007257, a Novel NAC Transcription Factor, Predicts Developmental and Synthesis Capabilities of Fiber Cells in Ramie (Boehmeria nivea L.)

NAC transcription factors are one of the largest transcription factor families in plants, and they play a key role in the growth and development of a secondary cell wall. Despite the fact that ramie is well-known for its high fiber yield, the role of NAC transcription factors in ramie secondary cell wall synthesis and fiber development remains unknown. In this study, based on our previous study, we describe the characterization, physicochemical property analysis, protein structure and function prediction, subcellular localization, and functional validation of Bnt05G007257, which encodes an NAC transcription factor from ramie, in transgenic A. thaliana. Our findings show that the open reading frame of Bnt05G007257 was 1035 bp long and encodes for a protein comprising 344 amino acids, having a relative molecular mass of 39.0945 kDa and a theoretical isoelectric point of 6.55. The secondary structure of the encoded protein mainly consisted of random coiling, with a typical conserved structural domain of NAC. The phylogenetic tree revealed that Bnt05G007257 is a homolog of the NAC transcription factor SND2, which regulates secondary wall biosynthesis in A. thaliana. Subcellular localization showed that Bnt05G007257 was tentatively predicted to be localized in the cytoplasm. Furthermore, in stem sections, the secondary wall fiber cells’ thickness in Bnt05G007257 transgenic plants was 31.50% thicker than that in wild-type plants, and the radial width was significantly increased by approximately 21.75%. This indicates that the NAC family homolog Bnt05G007257 may have the potential function of promoting fiber cell development and secondary cell wall synthesis, providing a theoretical basis for the selection of high-fiber-yielding ramie varieties in the future.

Mechanical property improvement of oil palm empty fruit bunch composites by hybridization using ramie fibers on epoxy–CNT matrices

Abstract Oil palm empty fruit bunches (OPEFBs) can be transformed into composite boards with higher selling value when their cellulose is used as a fiber. Manufacturing composites with hybridization techniques can improve their properties. This study combined OPEFBs and ramie fibers in an epoxy–carbon nanotube (CNT) matrix. The proportion of OPEFBs and ramie fibers was varied (3:7, 5:5, and 7:3), with a total fiber content of 10% by volume and a matrix of 90% by volume. Alkali treatment using NaOH solution was applied to the fiber to remove impurities from the surface. CNTs were functionalized using nitric acid followed by hydrogen peroxide to improve compatibility. Surface treatment was conducted on fibers and CNTs to increase the bonds between these components in the composite material. The hybridization of OPEFBs/ramie fibers improved the tensile strength in the 3:7TR, 5:5TR, and 7:3TR composites by 127, 37, and 12%, respectively, compared to the 10T composite. The flexural strength of the 5:5TR hybrid composite increased by 120%, and that of the 3:7TR and 7:3TR composites increased by 83% against the 10R composite. The 3:7TR hybrid composite showed the best mechanical properties.

Ramie Fiber Woven Composite: The Effect of Feedrate Variation on the Tensile Strength of the Open Hole in the Drilling

Composite with woven ramie as reinforcement is a combination of woven from hemp plant fibers with resin adhesive (matrix) which each has different characteristics, which with the combination will produce a new material with better properties. The purpose of this study is to determine the magnitude of the influence of federate variations on the tensile strength of open holes in drilling, with the test method carried out with reference to ASTM D 5766/D 5766M-02 (Standard Test Method for Open Hole Tensile Strength of Polymer Matrix Composite Laminates). The tensile test speed used is 5 mm/minute. The data taken is the maximum tensile strength when the specimen breaks. The results of this study indicate that the change in feed rate affects the tensile strength of the ramie composite. The greater the feed rate used is in grading the ramie fiber composite, the smaller the composite tensile stress value becomes. In this study, the highest tensile strength is obtained from composites with a feed rate of 0.05 mm/rev and the lowest at a feed rate of 0.15 mm/rev. The change in spindle speed also affects the magnitude of the tensile strength in the ramie composite. As with the feed rate speed, the greater the spindle speed used to grind the composite, the lower the tensile strength of the composite. In this study, the maximum tensile strength value tends to be obtained by a composite with a spindle speed of 88 rpm and the lowest at a spindle speed of 1500 rpm. This study uses the type of chisel "brad and spur" with three kinds of diameter variations. The larger the diameter of the drill chisel used, the smaller the tensile strength of the composite obtained.

Design and Parameter Optimization of Transverse-Feed Ramie Decorticator

In view of the elevated labor intensity and low efficiency of ramie fiber decortication, we designed a simple automatic ramie decortication machine in line with the characteristics of the ramie fiber decortication process, design requirements and market demand through an innovative design and theoretical analysis of key components such as the clamping and conveying device and the fiber detecting device, and identified the key factors and parameters affecting the quality of ramie decortication. We develop a mathematical model of the fiber percentage of fresh stalks and the ramie fiber impurity rate by considering decortication clearance, the drum speed, and the conveyance speed as factors, and determine the effect of operating parameters on ramie decortication and the optimal combination of parameters. Finally, a multi-objective optimization test was performed using the Box–Behnken test. In this paper, based on the results of the multi-objective parameter optimization analysis, the optimal parameters for ramie peeling were determined, namely, a decortication clearance of 3.7 mm, and a conveyance speed of 340 rpm. According to the optimized parameters, the ramie peeling process was experimentally validated. Using the optimized parameters, a validation test of the ramie direction in this study was performed. As indicated by the results, the percentage of fiber in the fresh stalk reached 5.05%, and the impurity rate in the ramie fiber was 1.24%. The relative errors of all metrics and model predictions were less than 5%, thus validating the accuracy of the prediction model. The machine achieved a production efficiency of 78.5 kg·h−1, which is in line with the design specifications. The raw fiber had a gum content of 23.45 percent, and the stripped fiber met the national standard for secondary ramekin fiber. This study lays a theoretical basis while providing technical support for fully automatic ramie decorticators.

Performance Optimization of Lignocellulosic Fiber-Reinforced Brake Friction Composite Materials Using an Integrated CRITIC-CODAS-Based Decision-Making Approach

A hybrid multicriteria decision-making (MCDM) framework, namely “criteria importance through inter-criteria correlation-combinative distance-based assessment” (CRITIC-CODAS) is introduced to rank automotive brake friction composite materials based on their physical and tribological properties. The ranking analysis was performed on ten brake friction composite material alternatives that contained varying proportions (5% and 10% by weight) of hemp, ramie, pineapple, banana, and Kevlar fibers. The properties of alternatives such as density, porosity, compressibility, friction coefficient, fade-recovery performance, friction fluctuation, cost, and carbon footprint were used as selection criteria. An increase in natural fiber content resulted in a decrease in density, along with an increase in porosity and compressibility. The composite with 5 wt.% Kevlar fiber showed the highest coefficient of friction, while the 5 wt.% ramie fiber-based composites exhibited the lowest levels of fade and friction fluctuations. The wear performance was highest in the composite containing 10 wt.% Kevlar fiber, while the composite with 10 wt.% ramie fiber exhibited the highest recovery. The results indicate that including different fibers in varying amounts can affect the evaluated performance criteria. A hybrid CRITIC-CODAS decision-making technique was used to select the optimal brake friction composite. The findings of this approach revealed that adding 10 wt.% banana fiber to the brake friction composite can give the optimal combination of evaluated properties. A sensitivity analysis was performed on several weight exchange scenarios to see the stability of the ranking results. Using Spearman’s correlation with the ranking outcomes from other MCDM techniques, the suggested decision-making framework was further verified, demonstrating its effectiveness and stability.