Experimental investigation on the mechanical properties of Cyperus pangorei fibers and jute fiber-based natural fiber composites

The present era uses natural fibers as a partial replacement for synthetic fibers, thereby utilizing eco-friendly materials in a number of automotive applications (namely, bumpers, wind shields, doors, ceilings, etc.). Although there are many research findings related to natural fiber composites, in this work, a new sandwich layer of Cyperus pangorei fibers and jute fiber epoxy hybrid composites is developed using the hand lay-up technique and compared with the pure Cyperus pangorei fiber and pure jute fiber epoxy composites. The mechanical properties like tensile, flexural, compressive, impact, and hardness are performed as per ASTM standards for the developed composites. The test results show that Cyperus pangorei hybrid composite 3 had a tensile strength of 50.2 MPa, flexural strength of 301.48 N mm^?2, ultimate compression load of 15.03 KN, impact energy of 6.34 J, and Shore D hardness of 82.7, which are superior by 1.1–1.5 times to all the other developed composites. The microstructural characterizations are performed using scanning electron microscope which played a vital role in analyzing the failure morphology of the composites.     

Impact of alkali treatment on physico-chemical,thermal, structural and tensile properties of Carica papaya bark fibers

This study aims to examine the effect of sodium hydroxide (NaOH) treatment on the physico-chemical properties, structure, thermal, tensile and surface topography of Carica papaya fibers (CPFs). The surface of raw CPFs was modified by soaking with 5% NaOH solution for 15, 30, 45, 60, 75 and 90?min. The results of thermo-gravimetric analysis revealed that the optimum treatment time for alkali treatment was 60?min. It was found that the alkali treatment improved the properties of the CPFs. The results of TGA, FT-IR, XRD and AFM suggest that the treated CPF is a suitable alternative as reinforcement in polymer composites.     

Impact of surface adaptation and Acacia nilotica biofiller on static and dynamic properties of sisal fiber composite

Nowadays, the awareness of the public along with strict legitimate forces over the use of polymers, the manufacturing and automotive industries started using the renewable materials. Since, natural fiber reinforced composites play vital role in developing lightweight structural materials, this study focuses on utilizing sisal fiber as reinforcement in polyester matrix along with natural filler. The influence of fiber length and fiber volume fraction on the mechanical properties of sisal fiber was studied initially. Test results revealed that the composite with 20?mm fiber length and 20-volume fraction composite has better mechanical properties. Furthermore, the effect of fiber surface modification has been analyzed using various chemical solutions such as NaOH, KMnO₄, stearic acid, and maleic acid. Of these, NaOH treatment enhances the mechanical properties of composite compared to all other cases. Finally, the influence of Acacia nilotica, a natural filler addition into the alkali-treated sisal fiber composite has been evaluated by mechanical and dynamic mechanical properties. It is found that the addition of natural filler and surface treatment has enhanced the properties of composites due to their synergetic effect. This effect improves the adhesion and uniform stress transfer among the reinforcements. The fiber surface morphology was evaluated using micrographs obtained from scanning electron microscope.     

Characterization of new natural cellulosic fiber from kusha grass

The present research work aimed to characterize new natural cellulosic kusha fibers extracted from the kusha grass plants. The physical and chemical properties of kusha fibers such as cellulose content (70.58%), lignin (14.35%), wax content (1.52%), ash content (2.46%), moisture content (8.01%), and density (1.1025 g cc^?1) were identified. An X-ray diffraction of kusha fibers confirms the presence of cellulose with a crystalline index of 55.4%. Fourier transform infrared spectroscopy analysis was carried out to establish the certainty of using them as reinforcement fiber. Thermogravimetric analysis ensures thermal stability up to 357°C which is within the polymerization process temperature.     

Physico-chemical properties of new cellulosic fibers from the bark of Acacia planifrons

Identification of new natural fibers is growing due to their superior properties and the impetus for researchers to develop high-performance composites. This investigation was aimed at understanding the physico-chemical properties of Acacia planifrons fibers (APFs). The crystalline structure of APFs was analyzed by X-ray diffraction, and the crystallinity index (65.38%) was calculated. The chemical functional group of APFs was confirmed by Fourier transform-infrared spectroscopy, the thermal stability measured by thermogravimetric analysis, and surface characterization established by atomic force microscopy. Taken together, all the properties of APFs can play a vital role in establishing APFs as new reinforcement in polymer composites.     

Characterization of New Natural Cellulosic Fiber from Acacia leucophloea Bark

There is a need to explore the possibility of natural fibers as a novel reinforcement to fabricate lightweight composite structures. This investigation was aimed at understanding the characteristics of fiber extracted from the bark of the Acacia leucophloea (AL) plant and its physico-chemical properties. Cellulose content (68.09 wt.%), density (1385 kg/m³), crystallinity index (51%), tensile strength (317–1608 MPa), and Young’s modulus (8.41 ? 69.61 GPa) properties were identified in the AL fibers, and thermal studies using TG and DTG analysis revealed that they degraded at a temperature of 220°C with kinetic activation energy of 73.1 kJ/mol.     

Optimization of short Indian Areca fruit husk fiber (Areca catechu L.)–reinforced polymer composites for maximizing mechanical properties

Natural fibers are being used as reinforcing materials for polymer composites due to their eco-friendly properties. Areca fruit husk fiber (AFHF) is one such fiber; it is currently discarded waste from the tobacco industry, but has huge potential. It is light in weight with a perforated surface that enables good bonding with a polymer matrix. In this study, comprehensive characterization of physical, chemical, thermal, mechanical, and microstructural properties was carried out on the fiber and the composite made with that fiber to optimize the fiber content. The optimum fiber content is found to be 40 wt.%, whereas beyond that, fiber pull-out and debonding reduces the load-bearing capacity of the composite. The specific properties of AFHF polymer composite are even higher than that of the popular E-glass fiber composite, which positions AFHF composite as an alternative structural material.     

Extraction,modification, and characterization of natural ligno-cellulosic fiber strands from napier grass

Napier grass is a high-productivity perennial grass that is a very important forage for animals in the tropics. In this research work, fiber strands from Napier grass were extracted and the effect of acetic acid treatment on their chemical composition, morphological and structural changes, and tensile and thermal properties was studied. The acid treatment was carried out using glacial acetic acid solution at three different concentrations (5, 10, and 15%) for 2 h. Chemical analysis indicated lowering of amorphous hemicellulose content on acid treatment. FT-IR spectroscopic studies revealed variation of functional groups on acid treatment. Scanning electron micrographs indicated roughening of the surface of the fiber strands due to the removal of the hemicellulose layer on acid treatment. X-ray diffraction analysis indicated an increase in crystallinity of the fiber strands on acid treatment. The thermal stability and tensile properties of the fiber strands increased on acid treatment. This fiber has competitive advantages when evaluated with other natural fibers and can be developed further as a potential reinforcement in polymer matrix composites.     

A Hexagonal Covalent Porphyrin Framework as an Efficient Support for Gold Nanoparticles toward Catalytic Reduction of 4‐Nitrophenol

A hexagonal porphyrin‐based porous organic polymer, namely, CPF‐1, was constructed by 3+2 ketoenamine condensation of the C₂‐symmetric porphyrin diamine 5,15‐bis(4‐aminophenyl)‐10,20‐diphenylporphyrin and 1,3,5‐triformylphloroglucinol. This material exhibits permanent porosity and excellent thermal and chemical stability. CPF‐1 can be employed as a superior supporting substrate to immobilize Au nanoparticles (NPs) as a result of the strong interactions between Au NPs and the CPF support. An Au@CPF‐1 hybrid was synthesized by an interfacial solution infiltration method with NaBH₄ as reducing agent. Au NPs (5 nm) grew on CPF‐1 and were distributed without aggregation. Moreover, Au@CPF‐1 exhibits superior catalytic activity compared to many other reported Au‐based catalysts for the reduction of 4‐nitrophenol in the presence of NaBH₄. In addition, Au@CPF‐1 has excellent stability and recyclability, and it can be reused for three successive reaction cycles without loss of activity. The dense distribution of phenyl rings on the channel walls of the CPF support can reasonably be regarded as the active sites that adsorb the 4‐nitrophenol molecule through hydrogen‐bonding and C?H ??? π interactions, as was confirmed by the X‐ray structure of model compound DAPP‐Benz.     

Physico-chemical,Tensile, and Thermal Characterization of Napier Grass (Native African) Fiber Strands

This article presents the extraction and effect of alkali treatment on the physical, chemical, tensile, and thermal characteristics of fiber strands obtained from Napier grass, a renewable biomass. In order to improve these properties, the Napier grass fiber strands were treated with sodium hydroxide. The alkali treatment was carried out using NaOH solution at three different concentrations (5, 10, and 15%) for 2 h. Characterization of untreated and alkali-treated Napier grass fiber strands was carried out by studying the chemical composition, surface morphology, functional group variation, crystallinity, and tensile and thermal behavior. It was found that untreated fiber strands have lower cellulose content, crystallinity, tensile properties, and thermal stability than alkali-treated fiber strands. Napier grass fiber strands treated with 10% NaOH showed optimum tensile strength, modulus, and percentage elongation with an improvement of 51.9, 47.3, and 12.1% respectively. Based on the properties determined for alkali-treated Napier grass fiber strands, we expect that these fibers will be suitable for use as a reinforcement in natural fiber composites.     

Characterization of new natural cellulosic fiber from the Ipomoea staphylina plant

Natural fibers extracted from plants play a major role as reinforcement in polymer composite materials due to their superior properties. This work aims to comprehensively characterize the physical and chemical properties of Ipomoea staphylina fibers (ISFs), which are extracted from the stem of the Ipomoea staphylina plant. The ISFs show cellulose content (72.76 wt%), hemicelluloses content (13.6 wt%), density (1401 kg cm^?3), and tensile strength of 173–658 MPa with a strain rate of 2.03–6.63%. The thermal stability of ISFs illustrate that the fibers are stable up to a temperature of 311°C with kinetic activation energy of 99.82 kJ mol^?1.     

Three-phase cyanate ester composites with fumed silica and negative-CTE reinforcements

Three-phase cyanate ester adhesives have been developed using a bisphenol E cyanate ester resin, fumed silica, and negative-CTE (coefficient of thermal expansion) reinforcements: short carbon fiber or zirconium tungstate (ZrW₂O ₈ ). Fumed silica was used to impart thixotropic behavior on the resin and decrease settling in the adhesives. The cured composites were evaluated using various thermal analysis techniques for their thermal-mechanical properties. Composites with short carbon fiber showed enhanced modulus and decreased thermal expansion (70% reduction for 20 vol%) and showed little phase separation. While settling of the dense ceramic particles could not be completely eliminated for the zirconium tungstate composites through rheological modification of the adhesive with added fumed silica, a reduction in CTE of 84% was achieved in the composite (58 vol%) compared to the neat resin. In addition, the effect of thermal history on the cure and temperature induced ZrW₂O₈ phase transitions, and their corresponding influence on thermal strains vs. temperature, are examined by thermomechanical analysis.     

A new study on effect of various chemical treatments on Agave Americana fiber for composite reinforcement: Physico-chemical,thermal, mechanical and morphological properties

This research is focused to fundamentally understand the benefits of using Agave Americana C. plant as potential reinforcement in polymeric composites. The fibers were extracted from the external part of the bark of the plant, which grows worldwide in pastures, grasslands, open woodlands, coastal and riparian zones. In order to use the natural fiber as reinforcement it is paramount important to probe their chemical composition, microstructural behavior and mechanical properties. Hence, firstly the extracted fibers were chemically treated with NaOH, stearic acid, benzoyl peroxide and potassium permanganate. The chemical composition in terms of cellulose, hemicellulose, lignin and other waxy substances were determined using a standard TAPPI method. FT-IR technique was used to understand the character of molecular bonds, crystallinity and their correlations with various bonds in fiber structure. The thermal stability was investigated through thermogravimetric and differential scanning calorimetric analysis, and the mechanical characterization was performed by applying standard tensile test. The surface morphology of fibers was examined through scanning electron microscopy (SEM) and finally reliability scrutiny of all the analysis was carried out. The results of chemical modification techniques applied on the surfaces of natural fibers allows to produce superior fibers used to form the novel composite materials for light-weight application.     

Filled grades of chemically modified poly(ethylene terephthalate)

Structural phases and blends properties of glass fiber filled reactive PET/R‐PE blends (85/15 and 75/25 wt/wt) were studied in a chemical modification involving reactive extrusion with a ricinyl‐2‐oxazoline maleate. The present method offers compatible heterogenous blends with the structure stabilized at microphase level and with advantageous macroscopic properties, viz., impact and tensile resistance, processability. The most important effects of glass fiber reinforcement are increases in strength (tensile and flexural) and stiffness (flexural modulus).     

Effect of Chemical Treatments on Physicochemical Properties of Prosopis juliflora Fibers

Incompatibility between hydrophilic natural fibers and hydrophobic matrix is known to affect the adhesion of the fiber and matrix. Therefore, it becomes necessary to modify the surface of natural fibers for improved adhesion between the fiber and matrix. Prosopis juliflora fibers (PJFs) are known to possess desirable properties for use as reinforcement in polymer matrices. Using chemical analysis, the optimal condition for alkali treatment of the PJFs was found to be 5% (w/v) of NaOH concentration with 60 min soaking time. Chemical modifications favorably changed the physiochemical properties of PJFs and undoubtedly diminished the amorphous and wax contents.     

Extraction and characterization of natural cellulosic fiber from Passiflora foetida stem

This article presents a comprehensive characterization study of natural cellulosic fiber extracted from Passiflora foetida vine stem. The chemical composition of the obtained P. foetida fibers (PFFs) comprised high cellulose (77.9 wt%) and low lignin (10.47 wt%) content and had distinctly higher crystallinity (67.36%) of cellulose, which was determined by an X-ray diffractometer. The PFFs exhibited good tensile strength of 248?942 MPa associated with elongation (1.38?4.67%) during tensile testing. Thermogravimetric analysis revealed that the PFFs are thermally stable up to 320°C with kinetic activation energy of 85.46 kJ mol^?1; hence they ensure their suitability as a reinforcing phase in composites for potential applications.     

Extraction and characterization of lignocellulosic fibers from Luffa cylindrica fruit

The need for recyclable, renewable materials has resulted in an increased use of natural fibers for reinforcing polymers to suit a wide variety of applications. This study is mainly focused on the extraction and characterization of the lignocellulosic fibers derived from the ripened, dried Luffa cylindrica L. fruit. Characterization studies such as Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis are conducted and reported. Composite samples prepared using unsaturated polyester resin show an increasing impact strength on fiber loading. Fractured surface of the composites are examined using scanning electron microscope. Results show the feasibility of fibers for reinforcement in polymers.     

The effect of grass fiber filler on curing characteristics and mechanical properties of natural rubber

Natural rubber is reinforced with a novel type of grass fiber (Cyperus Tegetum Rox b). The effects of fiber loading of different mesh sizes on curing characteristics and mechanical properties of grass fiber filled natural rubber composite are studied. Since 400 mesh grass fiber loaded natural rubber composite shows superior mechanical properties, therefore the effect of silane coupling agent was studied for this particular composite. Here composites were prepared by using water leached grass fiber. Optimum cure time increases with the increase in fiber loading but the change in scorch time is less. The same trend of increase in optimum cure time is observed in the presence of Si69. But the value is higher compared to that of rubber composite without Si69. With increase in the fiber loading, modulus and hardness of the composite increases but tensile strength decreases. The mechanical properties of the composite, namely moduli at 200 and 300% elongation and hardness increase in the presence of Si69 but tensile strength is less compared to that of the composite without Si69. Elongation at break is not much affected due to the presence of Si69. Copyright © 2004 John Wiley & Sons, Ltd.     

Characterization of new natural cellulosic fiber from the Perotis indica plant

This investigation summarizes the characteristics of biofiber extracted from the Perotis indica plant. Cellulose content (68.4 wt%), density (785 kg m^?3), crystallinity index (48.3%), tensile strength (317–1,608 MPa), and Young’s modulus (8.41–69.61 GPa) properties were identified in the P. indica fibers (PIFs), and thermal stability was studied using thermal gravimetric analysis and derivative thermogravimetric analysis, which revealed its cellulose degradation at a temperature of 339.1°C. Further, the properties of PIFs ensured that it can play an imperative role as new reinforcement as green composites in the manufacturing industries.     

Nanofiller‐reinforced polymer nanocomposites

In this work, the technology of nano‐ and micro‐scale particle reinforcement concerning various polymeric fiber‐reinforced systems including polyamides (PAs), polyesters, polyurethanes (PUs), polypropylenes (pps), and high‐performance/temperature engineering polymers such as polyimide (PI), poly(ether ether ketone) (PEEK), polyarylacetylene (PAA), and poly p‐phenylene benzobisoxazole (PBO) is reviewed. When the diameters of polymer fiber materials are shrunk from micrometers to submicrons or nanometers, there appear several unique characteristics such as very large surface area to volume ratio (this ratio for a nanofiber can be as large as 10³ times of that of a microfiber), flexibility in surface functionalities and superior mechanical performance (such as stiffness and tensile strength) compared to any other known form of the material. While nanoparticle reinforcement of fiber‐reinforced composites has been shown to be a possibility, much work remains to be performed in order to understand how nanoreinforcement results in dramatic changes in material properties. The understanding of these phenomena will facilitate their extension to the reinforcement of more complicated anisotropic structures and advanced polymeric composite systems. Copyright © 2008 John Wiley & Sons, Ltd.