Mechanical,morphological, and thermogravimetric analysis of alkali-treated Cordia-Dichotoma natural fiber composites

ABSTRACT

Usage of composites with natural fiber reinforcement is drastically increasing in recent times because of their low density, biodegradable nature, and low cost. However, natural fibers have certain core problems such as poor adhesion between the fiber and matrix and a relatively high degree of moisture absorption. Alkaline treatment of natural fibers is aimed at improving the adhesive strength so that effective stress transferability takes place in the composite. In the present work, Cordia-Dichotoma fibers were treated with sodium hydroxide (NaOH) and composites were prepared with different weight ratios of these fibers reinforced with epoxy. The prepared composites were tested for their tensile and flexural strengths (mechanical properties). Besides, for a comprehensive material characterization, IR spectroscopy (FT-IR), scanning electron microscope, and thermogravimetric analysis were carried out. This work investigates the influence of aforementioned NaOH treatment on thermal, mechanical, and morphological properties of the composite material.     

Effectiveness of Alkali and Sodium Bicarbonate Treatments on Sugar Palm Fiber: Mechanical,Thermal, and Chemical Investigations

ABSTRACT

Sugar palm fiber (SPF) as one of the attractive natural fibers to reinforce matrix is gaining attention. This is largely due to its similar properties when compared with other established natural fibers. The aim of this study is to investigate the effectiveness of sodium bicarbonate as a treatment chemical for SPF in comparison with established alkaline treatment. Both treated and untreated fibers were characterized and it was found that the treated fiber shows an increase in crystallinity, thermal stability, and surface’s roughness when compared with the untreated. Among the two different treatments, SPF treated with alkali has an initial decomposition temperature of 255.47°C, while sodium bicarbonate treated and untreated fibers have 250.19°C and 246.76°C, respectively. In both cases, the thermal stability of the fiber was improved. Also, as revealed by the X-ray diffraction (XRD) analysis, the crystallinity index of SPF treated with alkali and sodium bicarbonate increased by 18.43% and 13.60%, respectively, when compared with untreated fiber. In conclusion, the investigation proved that treatment with the sodium bicarbonate has a significant effect on the physicochemical properties of SPF and the chemical could be an alternative chemical for treating other cellulose fibers.     

Optimization of the alternative treatment methods for Ceiba pentandra (L.) Gaertn (kapok) fiber using response surface methodology

Abstract

Ceiba pentandra (L.) Gaertn (kapok) fiber, a natural and renewable material, has received increasing attention in recent years for its intrinsic properties. In this study, pretreatment of kapok fiber was performed in a green way by using atmospheric plasma, together with pectinase and lipase enzymes and no hazardous chemicals was used. A response surface methodology (Box-Behnken experimental design) has been used to design and optimize an environmentally friendly and sustainable scouring process for kapok fibers. Predicted values provided from regression model and the actual experimental values exhibited close relationship. The effects of the treatments on the hydrophility, whiteness index and color yield of the kapok fibers have been discussed. The structure of the fibers was investigated by scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analyses. Results showed that atmospheric plasma?+?pectinase and atmospheric plasma?+?lipase treatments are ecofriendly alternatives for kapok fiber treatments.     

Characterization of natural cellulosic fiber from Epipremnum aureum stem

The natural fiber Epipremnum aureum was extracted from its plant. E. aureum fibers (EAFs) were investigated by chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and single fiber tensile test. Chemical analysis, FTIR, and X-ray analysis evidenced that these fibers has 66.34% cellulose content with crystallinity index of 49.33%. The thermogravimetric analysis reveals that EAFs can thermally withstand temperatures until 328.9°C. The morphology of the EAFs was observed by scanning electron microscope. It was established that the fiber can be utilized as reinforcement in polymer composites.     

Influence of chemical treatment on tensile strength,water absorption,surface morphology,and thermal analysis of areca sheath fibers

Proper surface modification is highly essential to improve compatibility of natural fibers with polymer matrix to develop eco-friendly materials. In the present work, an attempt has been made to study the effect of various chemical treatments such as alkaline, acrylic acid, permanganate, sodium chlorite, and benzoylation on areca sheath fiber. After surface modifications, its density, water absorption property, mechanical property, thermal gravimetry analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and surface morphology have been thoroughly investigated. It has been observed that benzoyl chloride-treated fiber gives better performance in comparison to other treatments.     

Tensile,flexural, impact,and hardness properties of alkaline-treated Sunnhemp fiber reinforced polyester composites

ABSTRACT

The natural fibers and their specific properties attracted researchers in the recent years for the development of new polymer composites. In this way, the Crotalaria juncea L. (Sunnhemp) fiber was identified as a potential material for reinforcement and the preparation of polyester-based polymer matrix composites was carried out. The present investigation was focused on fabrication of untreated and alkaline-treated C. juncea L. (Sunnhemp)–polyester composite laminates and the evaluation of tensile, flexural, impact, and hardness properties as per ASTM. The different kinds of fiber orientations such as random, continuous, biaxial, and triaxial were considered and the properties were evaluated.     

Electro-conductive Palmyra Fibers By In Situ Polymerization of Pyrrole

Palmyra (Borassus flabellifer L.) is one of the natural fruit fibers that are available in plenty. This fiber has many advantages, such as biodegradability, renewability, low density, and low cost, which offer greater opportunities to develop new applications. Imparting electrical conductivity to this fiber may open up avenues for various novel applications. In the present study, Palmyra fibers are made electro-conductive by in situ chemical polymerization of pyrrole with FeCl₃ oxidant and PTSA dopant. Prepared electro-conductive fibers show average electrical resistivity 2.96 kΩ cm^?1. A positive correlation is found between fiber-length and electrical resistance, whereas a negative correlation is found in between fiber-diameter and electrical resistance. FTIR study is conducted to understand the chemical interaction between lingo-cellulose and polypyrrole. Tensile properties and thermal degradation behavior of the prepared electro-conductive fibers are evaluated, and significant deterioration of both tensile properties and thermal stability is observed. Due to this reason, these electro-conductive fibers are unsuitable for mechanical processing and high-tech applications. But the response of these fibers in different pH solution is investigated, and their possible application as a pH sensor has been explored.     

Extraction and Characterization of Lignocellulosic Fibers from Girardinia Bullosa (Steudel) Wedd. (Ethiopian Kusha Plant)

ABSTRACT

Currently, eco-friendly products have been given great attention as the world is being polluted severely by non-biodegradable products and by-products. Different textile products have their own share in affecting the environment. This research is focused on exploring alternative bast fiber products to support the supply chain and to assess the possibility of using this fiber as a substitute to already available bast fibers. Kusha fiber was extracted and optimized from Ethiopian kusha plant stem – Girardinia bullosa (Steudel) wedd. – using caustic soda solution by varying the concentration, temperature, and time using design expert 6.0.10, quadratic model software. Tensile property, chemical composition, X-ray diffractometer (XRD), Fourier-transform-infrared spectroscopy (FTIR), fiber morphology, and thermogravimetric analysis (TGA) of the fiber were determined. Fiber characterization showed its tensile strength, and the cellulose content was equivalent to or even better than other bast fibers. Morphology of the fiber was similar to that of typical cotton with visible lumen and a slightly flat surface. Therefore, this new extracted fiber has a great potential to be used for different applications such as fiber-reinforced composites, textile furnishing, apparel, and nanocellulose extraction.     

Improvement in mechanical properties of sponge-gourd fibers through different chemical treatment as demonstrated by utilization of the Weibull distribution model

ABSTRACT

Sponge-gourd natural fibers obtained from Luffa cylindrica plant were chemically treated separately using 5?15 wt% NaOH, acetic anhydride and benzoyl chloride solutions. Surface morphological, mechanical and thermal characteristics of untreated and chemically treated fibers were studied. Untreated and modified surfaces of the fibers were characterized by field emission scanning electron microscopy. Tensile tests were carried out by equal length of single fibers to obtain their mechanical properties. The two-parameter Weibull distribution model was applied to find the variation in mechanical properties. Tensile strength, elastic modulus and thermal stability of the fibers were found to significantly increase after chemical treatment.     

Morphology,Structure, and Mechanical Properties of Natural Cellulose Fiber from Mendong Grass (Fimbristylis globulosa)

This study was to investigate the morphology, structure, and chemical properties of the Mendong fibers extracted from Mendong grass (Fimbristylis globulosa) in the form of raw and treated fiber by alkali-included chemical content and functional group and to evaluate the strength and properties of Mendong fibers compared with other natural fibers. These studies explore the chemical properties of the fiber including fiber composition and functional group by FTIR, mechanical properties of fiber, and the structural and morphological analysis of the fiber using SEM and XRD. The results showed that the chemical contents of Mendong fibers were 72.14% cellulose, 20.2% hemicellulose, 3.44% lignin, 4.2% extractive, and moisture of 4.2%–5.2%. Mechanical properties of the fiber were a strong character with tensile strength of 452 MPa, and modulus of 17 GPa. The structural properties of Mendong fiber such as crystallinity, crystalline index, microfibril angle, and crystalline size were 70.17% and 58.6%, 22.9°, and 14.3 nm, respectively. This fiber has competitive advantages compared with other natural fibers and can be developed further as a potential reinforcement of polymer matrix composites.     

Coir Fiber–Process and Opportunities

Abstract

Growing environmental awareness throughout the world has triggered a paradigm shift towards designing materials compatible with the environment. Coira lignocelluosic natural fiberhas emerging importance as an engineering material due to its high tensile strength and elongation properties. The advantages of natural lignocellulosic fibers include acceptable specific strength properties, low cost, low density and biodegradability. This work is intended to present an overview of the main results presented in literature on this topic, focusing the attention on the fiber properties in terms of physical and chemical structure. Some aspects related to the traditional uses of coir fibers are also presented. Coir, as an ecofriendly fiber, has tremendous potential in India as well as the rest of the World for mattresses, fabric and other novel applications. Research and development efforts have been underway to find new use areas for coir.     

Polyvinyl Chloride Reinforced with Areca Sheath Fiber Composites—An Experimental Study

ABSTRACT

This research work deals with fibrous composites obtained by using treated and untreated areca sheath (AS) fibers reinforced in polyvinyl chloride (PVC) by injection molding process. Surface treatments of fibers have been carried out to have a better compatibility with PVC matrix. The tensile and flexural strength have been found to increase at the early stage with the increase in treated areca fiber content till optimum (18 wt% of fiber) fiber loading thereafter declines. At optimum fiber loading, the tensile strength, flexural strength and young’s modulus values are 42.38 MPa, 18.22 MPa and 2.38 GPa, respectively, which give maximum values in comparison to other fiber loadings. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), biodegradability tests and scanning electron microscopy (SEM) have been used for analysis. The TGA inferred that the thermal stability of the composites increased as compared to neat PVC matrix. Further, the composites exhibit excellent biodegradability property and their biodegradability increases with the increase of areca fiber content. From the properties obtained at optimum fiber loading (18 wt% of fiber), the composite can be suitable for automotive dashboard and door panel applications.     

Chemical,morphological and structural characteristics of crossbred wool fibers

Abstract

Crossbreeding of a local sheep called Ghezel thick wool with Arkharmerino fine wool is one of the interest studies in the last decade to improve the local sheep’s products quality. In this study, the chemical and mechanical properties of Arkharmerino, Ghezel and their first and second-generation wool fibers were investigated. The diameter, length and tensile properties of wool fibers were studied. The Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction and energy dispersive X-ray spectrum were also performed to evaluate the morphological and physical characteristics of all samples. The results showed that crossbreeding Ghezel ewes with Arkharmerino rams led to improving the wool fiber characteristics from chemical and physical properties points of view in the final application. The higher fineness, higher length, lighter color and higher tenacity were resulting from Arkharmerino–Ghezel in the second generation in comparison with Ghezel wool fibers.     

Comparative Study of Starch Fibers Obtained by Electro-spinning of Indigenous,Commercial and Cationic Potato Starch

ABSTRACT

By using the electro-spinning process on natural polymers, it is possible to obtain biodegradable membranes with potential applications in filters and scaffolds for tissue engineering. In this study, a comparison was made between the respective chemical, physical and thermal properties of the fibers from two sources of starch: One derived from a local, indigenous variety of potato (Diacol Capiro), native to the Boyacá region of Colombia (from here on referred to as “local starch”); the other, commercially available starch. A cationization of fibers was also carried out on the two starches. Chemical, physical and thermal properties were analyzed by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (DRX), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results showed the fibers were cationized with a highly amorphous state, with a heat resistance of 300°C from physicochemical changes generated in the fibers.     

Physico-chemical and mechanical characterization of alkali-treated Agave americana L. fiber

This study investigates the effect of mercerization on the physico-chemical and mechanical properties of Agave americana L. fiber. The alkali concentration is a crucial parameter which affects the crystallinity and the tenacity of the fiber. Treatments with low alkali concentrations produce fibers that are stronger than the untreated fibers and at this level the crystallinity reaches high values. However, treatments with high concentrations (>2% wt/v) result in weaker fibers with low crystallinity index. The chemical composition of A. americana L. fibers is also altered by the mercerization process insofar as the cellulose content increased with the NaOH concentration while the hemicelluloses and lignin contents decreased.     

Evaluation of Phormium Cookianum Fibers as Reinforcements for Polypropylene-based Composites

ABSTRACT

Due to the abundance of vegetable fibers from the large variety of existing plant types, many of them have not yet been explored in terms of mechanical behavior as composite reinforcements. Most of the natural fibers composites are based in a few crop fibers leaving a large number of species without a comprehensive study. This work evaluates the tensile strength of fibers from Phormium cookianum. Scanning electron microscopy images were taken on the fiber surface after the mercerization process, as well as in the composite. Through these results, it can be identified that the damage caused to the surface of the fibers may directly influence the adhesion that occurs at the interface with the polymer. In general, the composites produced here have good mechanical properties with a low cost of production. On this basis, this product has the potential to replace panels, boards, injection and molded parts.     

Some Properties of Natural Fibers (Sisal,Pineapple, and Banana) in Comparison to Man-Made Technical Fibers (Aramide,Glass, Carbon)

In this paper, we analyze the results of the delignification treatments performed on three natural fibers (sisal, pineapple, and banana) and of the thermal treatments at 400, 600, and 800°C on three industrial fibers (aramid, carbon, and glass). The fibers were analyzed by TGA, SEM, and EDS, as well as tested for tensile strength before and after the delignification and thermal treatments. Contact angle measurements were also carried out on the natural fibers. With the delignification treatments, the removal of Si, K, and Mg on pineapple and banana fibers was achieved. Thermal treatments lowered significantly the tensile strength of industrial fibers, while delignification treatments decreased slightly the mechanical resistance of natural fibers, except in the case of the pineapple fiber.     

Natural Bamboo (Neosinocalamus affinis Keng) Fiber Identification Using FT-IR and 2D-IR Correlation Spectroscopy

The objective of this study as to identify natural bamboo (Neosinocalamus affinis Keng) fiber through Fourier transform infrared spectroscopy (FT-IR), second derivative IR spectra, and two-dimensional infrared correlation spectroscopy (2D-IR). Textile plant fibers, including natural bamboo, jute, and flax fibers, were collected, and isolated by hydrogen peroxide and glacial acetic acid becoming single fibers to avoid uncontrolled influence. All the chemically treated plant fibers showed generally similar IR spectral profiles. However, different numbers of peaks in the range of 1,300–1,200/cm and the variation in peak intensity at around 1,059/cm were observed for bamboo fiber differentiation. A few differences in their second derivative IR spectra between bamboo fiber and the other plant fibers also provided information for differentiation. Furthermore, the characteristic features of bamboo fiber were presented in 2D-IR correlation synchronous spectra in the range of 800–1,200/cm and 1,425–1,750/cm, which were obviously distinguished from other investigated fibers. In addition, the results showed that the distinction between bamboo fiber and bamboo pulp fiber could be easily carried out using FT-IR and 2D-IR spectroscopy because of their different chemical compositions and crystal lattice types of cellulose (I, II). Therefore, it is demonstrated that FT-IR combined with 2D-IR correlation spectroscopy can become a new approach for natural bamboo fiber identification.     

Synthesis and Applications of Functional Polymers from Natural Okra Fibers for Removal of Cu(II) Ions from Aqueous Solution

Functional groups (?COOCH₃ and ?NH₂) in natural okra fiber had been introduced by free radical graft polymerization of methyl methacrylate (MMA) and acrylamide (AAm) from their binary solution using ascorbic acid/H₂O₂ as a redox initiator at a temperature of 45°C for 90 min. Factors affecting the grafting of lignocellulosic fiber such as feed molarity and comonomer composition were investigated. The grafted copolymers were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM-EDX), and thermogravimetric analysis (TGA). Functional groups were tested for their potential application in the removal of copper ions from aqueous solutions. Batch experiments were performed to evaluate the adsorption capacity of the maximum grafted cellulosic fibers toward the Cu (II) ions. Pseudo-first-order and pseudo-second-order kinetic models were studied to analyze the Cu²⁺ adsorption process and results showed that the pseudo-second-order model was more suitable than the pseudo-first-order model. Further, Langmuir, Freundlich, and Tempkin models were also applied to describe the adsorption isotherm of Cu²⁺ by different fiber adsorbents. The results indicate that the Langmuir model fitted the adsorption equilibrium data better than other two models. The maximum monolayer capacity q_m calculated using the Langmuir isotherm for raw and MMA+AAm grafted fiber were 4.89 and 33.05 mg/g, respectively.     

蕉麻纤维表面化学沉积纳米镍薄膜的形态研究

针对天然植物纤维功能单一及应用领域狭窄问题,通过化学溶液丝光化处理,获得不同形态的蕉麻纤维,再通过纤维表面硅烷接枝处理及常温化学镀等步骤,在蕉麻纤维表面生长纳米镍薄膜。采用扫描电子显微镜对纤维及纳米镍薄膜的表面形貌进行观察分析,结果显示,通过化学镀的方法使蕉麻纤维表面获得了致密的纳米镍薄膜,未处理纤维的表面纳米薄膜比较平整,而丝光化处理的纤维表面的纳米镍薄膜呈现出明显的微凸结构,说明可以通过化学处理蕉麻纤维基体来实现纳米镍薄膜微观形态的调控。