Non-treated Fiber Research Articles

Effects of plasma treatment on biodegradation of natural and synthetic fibers

This study investigates the application of plasma treatment as a means to enhance biodegradation and modify the structural characteristics of fibrous composites. The methodological component of the study includes the selection of the research object; production of composites; low-temperature plasma treatment, and treatment of biodegradability and mechanical strength of samples. The strengthening of fibers with cellulose leads to a significant improvement in mechanical strength. Such an indicator as mechanical strength increases from 18 to 21 MPa. Treatment of natural fibers with low-temperature plasma led to an increase in mechanical strength from 18 to 25 MPa. Treating reinforced fibers with low-temperature plasma currently results in an even greater enhancement in mechanical strength, increasing from 18 to 29 MPa.The electron microscopy of samples reveals some differences in cell wall microfibrils between plasma-treated and non-treated samples. The non-treated fibres are found to have chips and voids. Meantime, the plasma-treated fibres show structural changes in certain regions which resemble wood charring. Through a comprehensive analysis, this research underscores the substantial impact of plasma treatment on the degradation kinetics and morphological features of cellulose-based composites. The results reveal distinct alterations in the composition and behavior of plasma-treated fibres, signifying a shift towards enhanced biodegradability. The natural fibres examined in this study contained 28–30% lignin, whereas the composites exhibited a lower lignin content of 21–23%. These findings corroborate the inference that plasma treatment induces significant changes in fibre structure, accelerating the biodegradation process by 7 days.

Influence of surface treatments and addition of a reactive agent on the properties of PLA/flax and PLA/bamboo composites

Polylactic acid (PLA) composites reinforced with 10 wt% of flax (FF) or bamboo (BF) fibers were prepared via an internal mixer and/or twin-screw extrusion. Alkali pretreated fibers were soaked in silane to improve adhesion between fibers and matrix. 0.8 wt% of Joncryl™, a grafted copolymer acting as PLA chain extender, was also used alone or in combination with silane treatment of fibers to improve interfacial adhesion. The influence of silane treatment and/or Joncryl on the composite materials on mechanical, thermal and thermomechanical properties of materials processed through injection molding was investigated. Improved adhesion of the fibers to the matrix was shown using a scanning electron microscope. Fourier Transform Infrared Spectroscopy indicated that chemical bonds were formed between the silane coupling agent and fibers. X-ray Photo-electron Spectroscopy confirmed that fibers and silane derivatives were effectively coupled. XPS also highlighted that silane coupling agent reacted in higher amounts on bamboo than flax fibers, probably due to a higher amount of lignin in the case of bamboo fibers. Thermogravimetric analyses indicated that silane-treated flax and bamboo increased the thermal stability of the corresponding composites (PLA-SFF and PLA-SFB) compared to non-treated fiber composites. The incorporation of Joncryl alone entailed a degradation of the thermal stability of the corresponding composites (PLAJ-FF and PLAJ-FB) but enhanced the PLA/fibers interfacial adhesion. The combination of Joncryl and silane treatment resulted in strong improvements of thermal stability and interfacial adhesion for the PLAJ-SFF and PLAJ-SBF composites. Increase in tensile moduli and decrease in tensile strengths with the incorporation of the pristine fibers were noted. For silane-treated fibers, the tensile modulus and the strength of the corresponding composites were improved when adding Joncryl alone or in combination with silane. From also rheological and molar weight measurements, it could be concluded that Joncryl acts both as PLA chain extender and coupling agent.

The Use of Nontreated Fiber Obtained from Washingtonia filifera for Dye Removal from Aqueous Phases by Adsorption

The Use of Nontreated Fiber Obtained from Washingtonia filifera for Dye Removal from Aqueous Phases by Adsorption

Effect of sugar beet fiber and different hydrocolloids on rheological properties and quality of gluten-free muffins.

Extraction of pectin from sugar beet pulp is a side production line to recover value-added by-products in a sugar refining company. We aimed to evaluate the influence of depectinized and non-treated fiber on the quality of food. Pectin was removed from sugar beet pulp, and sugar beet fiber with and without pectin extraction (F and FP respectively) were replaced with rice flour in gluten-free muffins. To achieve a consistent texture, different hydrocolloids (carrageenan, xanthan gum, guar gum, locust bean gum (LBG), and tara gum) were added to the batter formula. The maximum batter viscosity was observed for the xanthan-containing formulation, followed by guar, tara, LBG, and carrageenan formulations. The highest hardness was recorded for baked muffins formulated with guar, followed by xanthan, carrageenan, tara, and LBG formula. Moisture retention was considerably increased in the presence of FP and LBG compared with muffins prepared by F and/or other hydrocolloids. However, muffins containing F showed the least hardness and highest cohesiveness, gumminess, springiness, and chewiness. The samples containing F represented lighter color, lower energy, and less porous in appearance compared with the FP formula. From a sensorial aspect, there was no significant difference between the F and FP formulas, but the control and sample with higher fiber content were not acceptable. This study showed that depectinized sugar beet fiber a by-product of sugar factories, has the possible use in formulation of gluten-free muffins with no adverse effects on its quality. © 2022 Society of Chemical Industry.

Piassava Fiber: A Novel Reinforcement for Cement-Based Matrix Composites

The addition of 2 and 5 wt% of piassava fiber, a natural lignocellulosic fiber extracted from a Brazilian palm tree botanically named Attallea funifera, into cement-based matrix composites was investigated. Both alkali-treated piassava fibers by NaOH and non-treated fibers were embedded in Portland cement, lime, and sand to fabricate mortars intended for civil construction. The non-aged fresh mortars were tested for paste consistency, water retention, and relative volume of incorporated air. Preliminary results showed that the addition of NaOH-treated piassava slightly increased the water retention while decreasing the incorporated air content. Together with these preliminary results, the comparatively low density of the piassava fiber allows the fabrication of novel cement-based composite with the potential to be used as mortar in building construction.

Innovative Green Way to Design Biobased Electrospun Fibers from Wheat Gluten and These Fibers' Potential as Absorbents of Biofluids.

In this study, a new method was developed to successfully design sustainable microfibers from wheat gluten proteins using a nonreducing solvent and electrospinning. We explored the morphology by X-ray tomography, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM), protein chemistry and cross-linking by size exclusion-high-performance liquid chromatography (SE-HPLC), and secondary structure by Fourier transform infrared spectroscopy (FT-IR) of fibers containing 15 and 20% of gluten. The impact of heat (130 °C) post-treatment on the polymerization properties of fibers and their absorption performance in different biofluids were also evaluated. The fibers with 20% gluten showed a uniform architecture supported by a relatively stronger fibrous network as compared to irregular and brittle fibers from 15% gluten. Heat treatment of fibers increased the protein cross-linking in all electrospun fibers as compared to the non-heat-treated fibers, as evidenced by SE-HPLC. An increase in the amount of α-helices and random coils was observed in the proteins of all of the heat-treated fibers compared to the nontreated fibers by FT-IR. This suggested that the heat treatment contributed positively to the gluten protein's chemical rearrangements, e.g., aggregation, new hydrogen and isopeptide bonding, and conversion of some of the sulfhydryl groups into disulfide cross-links, contributing positively to the functional performance. The heat-treated electrospun fibers with 20% gluten showed a very attractive blood absorption capacity (323%) and reasonable stability in phosphate-buffered saline (PBS) buffer compared to 15% gluten fibers and non-heat-treated fibers. Cotton-like fiber architecture, high blood absorption capacity, and reasonable stability in PBS buffer are properties desired for absorbents of biofluids and should be further explored in healthcare and medical applications.

The Effect of Jackfruit Skin Powder and Fiber Bleaching Treatment in PLA Composites with Incorporation of Thymol.

Food packaging has seen a growth in the use of materials derived from renewable resources such as poly(lactic acid) (PLA). However, the initial costs to produce bioplastics are typically high. Tropical fruit waste as naturally sourced fibres, such as jackfruit skin, can be used as a cost-reducing filler for PLA. The main objective in this study is to fabricate a low-cost natural fibre-reinforced polymer that potentially applies in packaging with the aid of bleaching treatment. The treatment shows a rougher surface fibre in Scanning electron microscopy (SEM) micrographs and it is expected to have better mechanical locking with the matrix, and this is found similar with a Fourier-transform infrared spectroscopy (FTIR) analysis. Unfortunately, fibre insertion does find low tensile performances, yet bleached-fibre composites improved its performance significantly. A similar situation was found in the thermal characterization where a low-thermal stability natural fibre composite has lower thermal behaviour and this increased with bleaching treatment. Besides, bleached-fibre composites have a longer service period. Besides, a 15 wt% thymol insertion inhibits the growth of Gram-positive bacteria in the composites and the non-treated fibre composite has better thymol effects. The 30 wt% of the bleached-fibre insertion composite has a high potential to reduce the cost of bioplastic products with minimum alterations of overall performances.

Analysis of unidirectional aligned Banana and Glass fiber reinforced polyester composite for tensile and flexural strength

The hybrid composite can be set up by utilizing at least two fiber fortifications in the composite. Here the hybrid composite was set up by utilizing banana/glass fiber. In addition, fiber volume loading was 40%. The tensile test and flexural test were preceded according to ASTM D3039 and ASTM D790 separately. The results show that 5% treated fiber shows higher properties than non-treated fiber composite. NaOH treated banana fiber with glass fiber composite shows higher quality as compared with non-treated in unidirectional continuous fiber reinforced composite.

Influence of Internal Stresses in Few-Mode Fiber on the Thermal Characteristics of Regenerated Gratings

The pre-treatment of few-mode fibers (FMFs) has been successfully done with CO2 laser. The wavelength difference, Δλ between the two resonant wavelengths in the few-mode fiber Bragg grating (FMFBG) varies with temperature increment during the annealing process. The results show that the treated fibers with lower stresses have lower thermal sensitivity in Δλ than that of non-treated fiber. However, the treated fibers produce FMFBGs with better thermal durability and regeneration ratio. It is conceived that the presence of those stresses in the pristine fiber is responsible for the high thermal sensitivity in Δλ. The thermal relaxation of stresses and structural rearrangement during the thermal annealing process are responsible for the degradation of the strength and resilience of the regenerated grating.

The Influences of Fibre Parameters on the Tensile and Flexural Response of Lightweight Thermoplastic Kenaf Fibre Reinforced Metal Composites

ABSTRACT The increasing demand for high performance and lightweight materials has stimulated the development of alternative materials, namely fiber metal laminates (FMLs). FML is a sandwich structure which is formed by bonding the metallic layers with composite as core constituent using an adhesive agent. In this study, the mechanical behavior of FMLs with the core constituents of environmental friendly kenaf bast fiber reinforced polypropylene composites bonded with aluminum skin layers was investigated. The effects of fiber compositions (50, 60, and 70 wt.%), fiber lengths (30, 60, 90 mm), and alkali treatment on the mechanical responses of FML were investigated. The overall results revealed that the increase of fiber composition and fiber length reduces the mechanical strength of FML owing to the agglomeration of natural fibers when the fiber length exceeds the critical limit. However, the chemical treated kenaf bast fiber reinforced FML showed a significant enhancement of the mechanical properties in comparison to the non-treated fiber reinforced FML owing to the improved fiber-matrix adhesion level.

Experimental description of strength and tribological characteristic of EFB oil palm fibres/epoxy composites with technologically undemanding preparation

Abstract Natural materials as fillers of polymers are of increasing potential in modern industrial branches. Their price as well as very good mechanical properties speaks for their use. The industrial application of natural fillers is also predetermined by economic aspects and a relationship to the environment - a prioritization of renewable resources when it is necessary to find adequate utilization for secondary materials coming into being e.g. in case of processing commodities of an oil palm - a palm oil. The paper describes basic strength characteristics of a short-fibre chaotic system with fibres gained from the waste - empty fruit bunches (EFB) - come into being during the process of the oil pressing. The experimental approach of this paper describes undemanding preparation of composite systems without using special technologies with a respect to needs of developing countries and simple applications above all. The experimental program compares the composite systems with non-treated fibres with the system with chemically treated surface of the fibres by 6% solution of NaOH. An electron microscopy was used for an evaluation of an interfacial interaction. The experiment describes short-fibre composites, studies the influence of the length (3, 6 and 9 mm) and the influence of the fibre concentration (2.5–10.0 vol %) on observed characteristics - tensile strength, module of elasticity, hardness and two-body abrasion. The chemical treatment of the fibre surface by the solution of NaOH influenced the surface structure of the fibres and it optimized the interaction of the fibres with used matrix. The inclusion of short EFB fibres increased the modulus of elasticity up of 47% and it decreased the tensile strength of 26%. EFB fibres did not significantly decrease an ability of the material to resist to the two-body abrasion. Described composite system and a production process can be marked as a sustainable manufacturing.

Enhancement of Mechanical Properties of Bio-Resin Epoxy/Flax Fiber Composites using Acetic Anhydride

Chemically treated acetic anhydride (AA) flax fiber mats were investigated. Bio-based epoxy resin and conventional epoxy resin unidirectional fiber composites were manufactured using a vacuum bagging technique. Flax fibers in the bio-resin composites were chemically treated with 1, 2, 3 and 4% (AA), while the fibers used with the conventional resin were not treated. The composites with the conventional resin were compared with the bio-resin in an untreated condition. A 2% AA treatment improved the bio-resin composite tensile strength, stiffness and bond shear strength by 55%, 58% and 7%, respectively. These three properties were evaluated and the results statistically analyzed using ANOVA. The AA reduced moisture absorption intake and improved adhesion of the fiber/matrix interface. The composites treated with 1–2% AA were most successful with a 65% moisture resistance. The scanning electron microscope was used to observe the fiber surface and fractured surfaces of the untreated and treated flax fibers. A chemical pre-treatment has improved the composite mechanical and moisture resistance over the non-treated fiber composites.

Antioxidant and Physicochemical Properties of Hydrogen Peroxide-Treated Sugar Beet Dietary Fibre.

The aim of the present work was to examine if hydrogen peroxide treatment of sugar beet fibre that aimed at improving its physicochemical properties would impair its antioxidant potential. Three different sugar beet fibres were obtained from sugar beet - non-treated fibre (NTF) from sugar beet cossettes extracted with sulphurous acid, treated fibre (TF) from NTF treated with hydrogen peroxide in alkaline solution and commercially available Fibrex(®) . The antioxidant activity of extractable and non-extractable fibre fractions in ethanol/water mixture (80:20, v/v) of three fibre samples was estimated. Non-extractable fractions obtained after alkaline treatment of investigated fibres were much higher in phenolic compounds and possessed higher antioxidant potential than extractable fractions. Ferulic acid was proven to be the dominant phenolic acid. Regarding both extractable and non-extractable fractions, Fibrex(®) had the highest antioxidant activity in chemical tests, while NTF was superior in comparison with TF. Based on the results of Caco-2 cells-based test, all non-extractable fractions possessed potential for reactive oxygen species inhibition. Regarding the extractable fractions, only the TF manifested this effect.Copyright © 2016 John Wiley & Sons, Ltd.

Fabrication and Testing of Pure and NaOH Treated Sisal Fibre Reinforced Bio-Composite

Natural fibres are now widely used for reinforcements of materials as they are a reliable resource and the cost is also less. One of the significant reasons of using natural fibres as reinforcements instead of polymers or other plastics is that they are degradable and don’t cause any harm to the environment. This article is particularly centered on polymer matrix composites made of Sisal fibre which was accessible locally and finding the composite’s mechanical property (tensile strength). A number of test samples of sisal fibre composite are fabricated by ASTM standards and made to undergo tensile tests in order to obtain the desired properties. In the later part of the work a comparison between the mechanical properties of a non-treated pure Sisal fibre composite and a NaOH treated Sisal fibre composite is carried out to check for any enhancements in the properties.

Improvement of degummed ramie fiber properties upon treatment with cellulase secreting immobilized A. larrymoorei A1.

Degummed ramie fiber is widely used in the textile industry. Cellulase enzyme can be effectively used for bio-polishing of the ramie fiber. We immobilized Agrobacterium larrymoorei A1, a potent extra-cellular cellulase producing bacteria, in Ca-alginate. The production of enzyme significantly increased with increasing alginate concentration and reached a maximum activity of 0.28 IU/ml at 20 g/l, which was 32% higher as compared to free cells. These immobilized cells were used on ramie fibers. Scanning electron micrograph (SEM) and differential interference contrast (DIC) studies showed increased smoothness and orientation of surface structure of the fibers after 19.5 h. The single fiber tenacity was almost same as compared to non-treated fiber and the initial modulus increased by 24.01%. The remarkable reusability of these immobilized cells provides a cost effective method for treatment of natural fibers containing cellulose.

Effect of surface treatment on the post-peak residual strength and toughness of polypropylene/polyethylene-blended fiber-reinforced concrete

This study involved an experimental investigation into the improvement of mechanical properties of fiber-reinforced concrete (FRC) utilizing chemically treated polypropylene/polyethylene fibers. Four types of chemical surface treatments were examined: two types of chromic acid (Types B and C), potassium permanganate (PP), and hydrogen peroxide solutions. Untreated and treated fibers were added at 0.32% by volume of concrete and also at 0.50% for the best treatment technique. Compressive and flexural strength were measured to quantify improvement. It was found that there were no significant differences in compressive strength. Type B chromic acid solution was found to be the most effective technique in improving the flexural strength of FRC resulting in average increases of 8.9% and 17.6% for peak and residual strengths, respectively, compared to nontreated fibers. While not as effective as plasma treatments, further research may be warranted for chemical treatments. Surface wettability of the treated fibers was measured by contact angle with water. The contact angle was found to have no correlation to the toughness. The higher volume of fibers, both treated and nontreated gave higher residual strength and toughness; however, surface treatment did not significantly enhance mechanical properties.

Charpy impact resistance of alkali treated curaua reinforced polyester composites

Natural fibers obtained from cellulose-based plants are being used as reinforcement of polymer composite owing to both environmental and technical advantages. One important technical characteristic of most lignocellulosic fibers is the bend flexibility, which allows them to resist impact forces. As a consequence, there is an increasing application of these lignocellulosic fibers in automobile parts that, during a crash event, should absorb the impact energy without splitting into sharp pieces. The present work investigates the toughness behavior of polyester composites reinforced with up to 30% in volume of alkali treated continuous and aligned curaua fibers by means of Charpy impact tests. It was found that the incorporation of treated curaua fibers increased the composite absorbed impact energy but not as much as in composites reinforced with non-treated fibers. Macroscopic observation, and scanning electron microscopy analysis of fracture surface, revealed that the main mechanism for the increase in the Charpy notch toughness is the interfacial rupture between the curaua fiber and the polyester matrix.

Absorption of carbon dioxide by mixed piperazine–alkanolamine absorbent in a plasma-modified polypropylene hollow fiber contactor

This paper examines the enhancement of hydrophobic plasma treatment on the performance of polypropylene (PP) hollow fibers in a gas absorption membrane (GAM) process using aqueous solutions of piperazine (PZ) and alkanolamine. Experiments were conducted at various gas flow rates, liquid flow rates, and absorbent concentrations. The CO 2 absorption flux increased with increasing gas flow rates and absorbent concentrations. The diffusion resistance of the liquid phase was only important when using 2-amino-2-methyl-1-propanol (AMP) or methyldiethanolamine (MDEA) as the sole absorbent. The diffusion resistance in the gas boundary layer is always dominant in the hollow-fiber CO 2 absorption processes. The water contact angle and roughness of the PP membrane increased by plasma treatment in CF 4. We show that the wetting ratio of the PP membranes decreased from 0.0674% to 0.027% after plasma treatment, when using mixed AMP–PZ solution as the absorbent. An 8% increase in the CO 2 absorption flux was observed for plasma-treated PP hollow fibers in comparison to non-treated fibers when using 1.0 mol/dm 3 AMP as the absorbent. Membrane durability was greatly improved by the treatment of plasma with CF 4 (20 W/5 min). The membrane mass transfer coefficient k m for plasma-treated PP membranes was comparable to that of polytetrafluoroethylene (PTFE) membranes.

The Application of Peach Palm Fibers as an Alternative to Fiber Reinforced Polyester Composites

The present work shows the behavior of non-treated and chemical pre-treated peach palm fibers, as reinforcement polymer composites. Chemical treatments with H2O2, NaOH, and C3H3N and their effects on adhesion performance of the fiber with unsaturated polyester resin are carried out. SEM is used to determine a time exposition of the fibers to chemical reagent and thermal characterization of these fibers after set time is performed. A hand lay-up method is applied to develop the composites and they are tested for tensile strength and Izod impact strength. The TGA of the fibers pre-treated with H2O2 20 V for 144 h show better thermal stability when compared with non-treated fiber. Other treatments do not improve their thermal properties.

Retention of mechanical properties and cytocompatibility of a phosphate‐based glass fiber/polylactic acid composite

Polymers prepared from polylactic acid (PLA) have found a multitude of uses as medical devices. The main advantage of having a material that degrades is so that an implant would not necessitate a second surgical event for removal. In addition, the biodegradation may offer other advantages. In this study, fibers produced from a quaternary phosphate-based glass (PBG) in the system 50P(2)O(5)-40CaO-5Na(2)O-5Fe(2)O(3) (nontreated and heat-treated) were used to reinforce the biodegradable polymer, PLA. Fiber properties were investigated, along with the mechanical and degradation properties and cytocompatibility of the composites produced. Retention of mechanical properties overtime was also evaluated. The mean fiber strength for the phosphate glass fibers was 456 MPa with a modulus value of 51.5 GPa. Weibull analysis revealed a shape and scale parameter value of 3.37 and 508, respectively. The flexural strength of the composites matched that for cortical bone; however, the modulus values were lower than those required for cortical bone. After 6 weeks of degradation in deionized water, 50% of the strength values obtained was maintained. The composite degradation properties revealed a 14% mass loss for the nontreated and a 10% mass loss for the heat-treated fiber composites. It was also seen that by heat-treating the fibers, chemical and physical degradation occurred much slower. The pH profiles also revealed that nontreated fibers degraded quicker, thus correlating well with the degradation profiles. The in vitro cell culture experiments revealed both PLA (alone) and the heat-treated fiber composites maintained higher cell viability as compared to the nontreated fiber composites. This was attributed to the slower degradation release profiles of the heat-treated composites as compared to the nontreated fiber composites. SEM analyses revealed a porous structure after degradation, and it is clear that there are possibilities here to tailor the distribution of porosity within polymer matrices.