Surface Modification Of Fibers Research Articles

Blended lime plasters with biomass ash and natural fibres reinforcement

Abstract The possibility to valorise biomass combustion ash in air lime based plaster was evaluated by means of mechanical properties. The possible effect of vegetable fibres (hemp, flax) was examined as well. The biomass ash improved significantly the mechanical properties of plaster. On the other hand, the vegetable fibres are limiting the compressive strength due to lower wettability between fibres and lime. However the fibres had positive effect on bending strength, as it is expected. The surface modification of fibres seems to be necessary in order to improve their performance in the lime system.

Surface modification of basalt fibers and its effect on the mechanical properties of basalt fiber/epoxy composite laminates

Surface modification of basalt fibers and its effect on the mechanical properties of basalt fiber/epoxy composite laminates

Hydrophobic or hydrophilic microhelices: Crafting surfaces with electrospun magnetic polystyrene fiber and an innovative top‐down technique

AbstractMicrohelices are important structures capable of overcoming low Reynolds number limitations and can be used in various applications. The fabrication of such microhelices is a challenge as existing fabrication techniques are restrictive in material choices and require sophisticated equipment. In this work, we demonstrate a simple top‐down approach to fabricate microhelical structures using surface modification of helical electrospun fibers to produce both hydrophilic, silica‐coated (Si‐HMPF), and hydrophobic, caramel sol‐based (Ca‐HMPF) magnetic microhelices post‐modification. The glassy coating obtained on the surface in both cases facilitated obtaining magnetic microhelices via mechanical fracture of the fibers by grinding at room temperature. SEM images of the samples confirm the successful fabrication of microhelical structures which resemble the popular microswimmer morphology. The FTIR and VSM characterization were performed to study the functional groups present and the magnetic nature of the fabricated microhelices. The thermal stability of the samples was investigated using DSC and TGA studies. Both hydrophilic and hydrophobic magnetic microhelices were successfully fabricated through a simple sol‐based coating technique and confirmed by a wettability study.Highlights Helical microstructures are an important classification of micro/nanomaterial synthesis. A simple method for the fabrication of magnetic polymeric microhelices is proposed and discussed in detail. The current challenges in fabricating such structures are discussed. The advantages of using a simple surface modification technique is summarized.

Tendon Decellularized Matrix Modified Fibrous Scaffolds with Porous and Crimped Microstructure for Tendon Regeneration.

Current engineered synthetic scaffolds fail to functionally repair and regenerate ruptured native tendon tissues, partly because they cannot satisfy both the unique biological and biomechanical properties of these tissues. Ideal scaffolds for tendon repair and regeneration need to provide porous topographic structures and biological cues necessary for the efficient infiltration and tenogenic differentiation of embedded stem cells. To obtain crimped and porous scaffolds, highly aligned poly(l-lactide) fibers were prepared by electrospinning followed by postprocessing. Through a mild and controlled hydrogen gas foaming technique, we successfully transformed the crimped fibrous mats into three-dimensional porous scaffolds without sacrificing the crimped microstructure. Porcine derived decellularized tendon matrix was then grafted onto this porous scaffold through fiber surface modification and carbodiimide chemistry. These biofunctionalized, crimped, and porous scaffolds supported the proliferation, migration, and tenogenic induction of tendon derived stem/progenitor cells, while enabling adhesion to native tendons. Together, our data suggest that these biofunctionalized scaffolds can be exploited as promising engineered scaffolds for the treatment of acute tendon rupture.

Surface modification of synthetic polymer fibers

Surface modification of synthetic polymer fibers

A Review on Surface Modification of Plant Fibers for Enhancing Properties of Biocomposites

AbstractOver the past decade, significant progress has been made in creating environmentally friendly products using natural resources. Plant fibers, also known as lignocellulosic fibers, are hydrophilic due to the interaction and attraction between water molecules and the hydroxyl groups present in their components. The inherent hydrophilicity of plant fibers often prevents them from interacting effectively with hydrophobic polymer matrices. In order to improve the adhesion between plant fibers and the matrix, it is necessary to modify the surface of the fibers. Commonly used chemical processes include mercerization, silane treatment, acetylation, permanganate treatment, acrylation, benzoylation, peroxide treatment, stearic acid treatment, isocyanate treatment and sodium chlorite intervention. The desirability of chemically modifying the surface of plant fibers has declined due to several limitations. Plant fibers can be modified in an environmentally friendly way by various methods, such as plasma therapy and treatments using fungi, enzymes and bacteria. This part provides an analysis of the impact of different environmentally friendly surface modification techniques on the properties of plant fibers and reinforced polymers.

Influence of CO2 laser surface treatment of basalt fibers on the mechanical properties of epoxy/basalt composites

AbstractIn fiber reinforced composite materials, the interfacial strength between the fibers and the matrix plays a key role in controlling the stress transfer and damage mechanisms of the composite. In this study, CO2 laser surface treatment of the fibers was investigated as a potential sustainable substitute for conventional chemical treatments, that can be costly and have negative environmental effects. The influence of the laser treatment on basalt fiber fabric was comprehensively investigated. The fibers were subjected to different laser power levels and characterized from a morphological and mechanical point of view. From optical and scanning electron microscopy, it was observed that the treated fibers manifested increased surface roughness along with spots of fused and bonded fibers. Individual treated fibers exhibited improved tensile properties with increased values of scale parameter (by about 21%) in the case of a laser power equal to 1.04 W/mm2, and no substantial changes in Young's modulus. The treated fibers were subsequently used in the preparation of epoxy‐based microcomposites, and microdebonding tests revealed an increase in the interfacial shear strength (IFSS) up to 8%. Therefore, this work proved that a laser surface treatment of basalt fibers is a valid alternative to conventional fiber surface modification to enhance the mechanical compatibility between fibers and matrix, and therefore to improve the mechanical performances of basalt fiber composites.Highlights Failure in composites due to weak interfacial adhesion with epoxy. CO2 laser treatment of basalt fibers to enhance interfacial adhesion. Treated fibers exhibit improved tensile properties. Treated fibers manifested improved interfacial shear strength (IFSS, +8%).

Mechanical improvement of carbon fiber/epoxy composites by sizing functionalized carbon nanotubes on fibers

AbstractA sizing agent mainly consisting of polyethersulfone and acidified multi‐walled carbon nanotubes (MWCNT) was developed for surface modification of carbon fibers (CF) to enhance the interfacial bond and to form carbon fiber‐carbon nanotube (CF‐MWCNT) multiscale reinforcements. To prepare the modified carbon fiber/epoxy resin composites (CFRP), a vacuum molding technique was used in this study. The effects of the MWCNT‐containing sizing agent on the morphology and chemical structure of the CF surface were observed by scanning electron microscopy and Fourier transform infrared spectroscopy. The influence of MWCNT length and content on the mechanical properties of CFRP were also studied. The experimental results showed that the strength of the CFRP decreased with the increase of MWCNT length, and the MWCNT with a content of 0.05 wt% had a good reinforced effect on the CFRP. After the sizing treatment, the interlaminar shear strength (ILSS) of the CFRP is increased. These enhancements are attributed to the improved mechanical bonding and chemical bonding between CF and resin matrix. The MWCNT provides nanosized rough surface to CF and these acidified MWCNTs attached to the surface of CF with polar oxygen‐containing functional groups improve the compatibility with reinforcement and resin matrix.Highlights Carbon fiber was modified by a sizing agent mainly consisting of polyethersulfone and acidified carbon nanotube (CNT). CNTs enhance the interfacial chemical bonding and mechanical bonding. The CNT length affects the mechanical properties of the carbon fiber/epoxy resin composites (CFRP). The modified carbon fiber has enhanced the mechanical properties of the CFRP.

Influence of density and chemical additives on paper mechanical properties

In this work we have investigated the effect of surface modification of fibres on the overall mechanical properties of high-density papers. Paper sheets were prepared by a combination of heat-pressing and polyelectrolyte Layer-by-Layer (LbL) modification of different softwood fibres. LbLs of Polyallylamine Hydrochloride (PAH) and Hyaluronic Acid (HA) were adsorbed onto unbleached kraft fibres and bleached Chemo-ThermoMechanical Pulp (CTMP) to improve the strength of the fibre–fibre joints in papers made from these fibres. Additionally, different sheet-making procedures were used to prepare a range of network densities with different degrees of fibre–fibre interaction in the system. The results demonstrate that interfacial adhesion within fibre–fibre joints plays a pivotal role in the network's performance, even at higher paper densities. Hygroexpansion measurements and fracture zone imaging with Scanning Electron Microscopy (SEM) further support the claim that stronger interactions between the fibres allow for a better utilisation of the inherent fibre properties. Surface treatments and network densification significantly improved the paper sheets' mechanical properties. Specifically, LbL-treatments alone increased specific stiffness up to 60% and specific strength by over 100%. This improvement is linked to the build-up of residual stresses during drying. Due to a high interaction between the fibres during water removal the fibres become constrained, leading to increased stretching of fibre segments. Strengthened fibre joints intensify this constraint, further increasing the stretch and, consequently, the paper's strength.

Binder-Free CNT-Modified Excellent Electrodes for All-Vanadium Redox Flow Batteries.

Electrodes are one of the key components that influence the performance of all-vanadium redox flow batteries (VRFBs). A porous graphite felt with modified fiber surfaces that can provide a high specific activation surface is preferred as the electrode of a VRFB. In this study, a simple binder-free approach is developed for preparing stable carbon nanotube modified graphite felt electrodes (CNT-GFs). Heat-treated graphite felt electrodes (H-GFs) are dip-coated using CNT homogeneous solution. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results conclude that CNT-GFs have less resistance, better reaction currents, and reversibility as compared to H-GF. Cell performances showed that CNT-GFs significantly improve the performance of a VRFB, especially for the CNT-GF served in the positive side of the VRFB. CNT presence increases the electrochemical properties of the graphite electrode; as a result, reaction kinetics for both VO2+/VO2+ and V3+/V2+ are improved. Positive CNT-GF (P-CNT-GF) configured VRFB exhibits voltage efficiency, coulombic efficiency, and energy efficiency of 85%, 97%, and 82%, respectively, at the operating current density of 100 mA cm-2. At high current density of 200 mA cm-2, the VRFB with P-CNT-GF shows 73%, 98%, and 72% of the voltage, coulombic, and energy efficiencies, respectively. The energy efficiency of the CNT-GF is 6% higher when compared with that of B-H-GF. The VRFB with CNT-GF can provide stable performance for 300 cycles at 200 mA cm-2.

Spider silk-inspired heterogeneous interphase featuring hybrid interaction for simultaneously improving the interfacial strength and fracture toughness between carbon fiber and epoxy by regulating hydrogen bond density

Designing advanced fiber-reinforced polymer composites through biological inspiration proved to be a crucial strategy for overcoming limitations in simultaneously enhancing the strength and toughness of composites. To achieve simultaneous improvement in the interfacial strength and toughness between carbon fiber (CF) and epoxy, a spider silk-inspired interphase featuring hybrid interaction was constructed by introducing hyperbranched polyamide-amine (HPAA) and graphene oxide (GO) onto the surface of CF. The results suggested that manipulating the feed ratio to adjust the branching degree of HPAA allowed for the attainment of various hydrogen bond densities. The fiber surface with high hydrogen bond density provided more hydrogen bond interaction sites to promote the deposition of GO. Benefitting from the ameliorative interfacial adhesion force, surface energy and interface thickness, impressive improvements of 94.5 % and 110.0 % in respective interfacial strength and fracture toughness over those of untreated CF/EP composites were achieved for functionalized CF/EP composites. The enhancement mechanism of interfacial performance was attributed to the formation of a “nano-fishnet” structure, which improved the stress transformation efficiency and consumption of external energy absorbed by hydrogen bonds. The method of regulating the branching degree of hyperbranched polymers and hydrogen bond density has opened an advanced way for surface modification of high-performance fibers.

Failure mechanism analysis and tensile constitutive model of basalt fiber concrete-rock interface based on fiber surface modification

This study investigates the tensile failure mechanism at the concrete-rock interface and proposes a concrete-rock interface tensile mechanical constitutive model considering the degree of rock surface indentation and surface morphology. The Brazilian disc splitting test results demonstrate that the depth and width of rock surface indentations collectively characterize the indentation angle θ, thereby influencing the tensile strength of the interface. Specifically, when 0° ≤ θ < 45°, the concrete-rock interface exhibits a tension-shear stress state, where cracks propagate along the interface leading to the debonding of the rock and concrete. When 45° ≤ θ ≤ 90°, the concrete-rock interface adopts a compression-shear state, with cracks gradually transitioning from the interface to the concrete interior. The latter scenario enables the higher tensile performance of the concrete-rock interface compared to interface fracture. Excessive indentation depth compromises the tensile strength of the interface by inducing bending moments. A mechanical model for the tensile behaviour of the concrete-rock interface is proposed, which effectively predicts the tensile strength of the interface and its evolutionary process.

Improving dispersion of basalt fiber with polyethylene glycol and effect of coupling agent

ABSTRACT Basalt fibers were widely used as reinforcing matrix materials because of their thermal and chemical stability and environmental friendliness. The properties of composite materials were affected by the interaction between the basalt fibers and matrix materials. Surface modification of basalt fibers and the dispersion property have become key points of research in recent years. This study focuses on the impact of a dispersant on surface modification. Basalt fibers were dispersed by polyethylene glycol (PEG) before modification with 3-aminopropyltriethoxysilane (KH550), which significantly increased the surface roughness, thus increasing the surface area and facilitating mechanical bonding. The morphology, structure, and composition were characterized via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy analysis (XPS), respectively. The distribution characteristics of fiber were evaluated by the response surface method. When the mass fraction of PEG was 0.5 wt.%, the modification time was 2.5 hours, and the modification temperature was 60°C, the fiber dispersion degree in KH550 solution reached 83%. The grafting degree test indicates that the weight of the grafting increased to 6.67 times that of the undispersed basalt fibers. This enhancement allowed for greater grafting of the KH550, thereby optimizing the effect of modified fibers.

Bamboo fiber reinforced poly (acrylonitrile-styrene-acrylic)/chlorinated polyethylene via compabilization

In the quest to enhance the performance of natural fiber-reinforced polymer composites, achieving optimal dispersion of fiber materials within a polymeric matrix has been identified as a key strategy. Traditional approaches, such as the surface modification of natural fibers, often necessitate the use of additional synthetic chemical processes, presenting a significant challenge. In this work, taking poly (acrylonitrile–styrene–acrylic) (ASA) and bamboo fiber (BF) as a model system, we attempt to use the elastomer-chlorinated polyethylene (CPE) as a compatibilizer to tailor the mechanical properties of ASA/CPE/BF ternary composites. It was found that increasing CPE content contributed to more remarkable reinforcing efficiency, where composite with 15 phr CPE exhibited a nearly four-fold increase in reinforcing efficiency of tensile strength (20 %) compared with that of composite system without CPE (4.1 %). Such improvement was ascribed to the compatibilizing effect exerted by CPE, which prevented the aggregation of BF within polymeric matrix. Surface properties suggested the stronger interface between CPE and BF compared to that between ASA and BF and thereby contributed to the compabilizing effect. Since no chemical process was involved, it is suggested that the introduction of elastomer to be a universal, green and sustainable approach to achieve the reinforcement.

Influence of Interfacial Interaction and Composition on Fracture Toughness and Impact Properties of Carbon Fiber-Reinforced Polyethersulfone.

In this study, the interlaminar fracture toughness and impact strength of polyethersulfone reinforced with continuous carbon fibers were studied. Interlaminar fracture toughness tests were performed using the double cantilever beam method. It was shown that surface modification using the thermal oxidation method of the carbon fibers can strongly increase the interlaminar fracture toughness of the obtained composites. Thus, the maximum value reached 1.72 kJ/m2, which was 40% higher than the fracture toughness of the composites reinforced with initial carbon fibers. Moreover, fractographic analysis using a scanning electron microscope allowed us to highlight the main reasons for the dependence of fracture toughness on fiber content and surface modification conditions of the carbon fibers. It was shown that the main factor that allowed for an increase in fracture toughness was the enhanced interfacial interaction between the fibers and polymer matrix. Additionally, it was found that expectedly, there was a good correlation between interlaminar fracture toughness and interlaminar shear strength results. However, a negative influence of surface modification on the impact properties of composites was found. Such behavior occurred because of higher structural stability and lower exposure to delamination in multiple layers of the composites reinforced with the modified carbon fibers. It was found that impact energy reached ~150 kJ/m2 for the polyethersulfone-based composites reinforced with initial fibers, while the composites reinforced with modified carbon fibers showed impact energy values of only ~80 kJ/m2. Nevertheless, surface modification of carbon fibers using the thermal oxidation method can be an effective method for improving the performance properties of polyethersulfone-based composite materials.

Plant fiber-reinforced green composite: A review on surface modification, properties, fabrications and applications

Plastic pollution has become a persistent challenge globally. The extensive production of disposable plastics overwhelms the world's ability to cope with. These non-biodegradable plastics accumulating in landfills, rivers, and seas cause severe damage to wildlife and the environment. The utilization of biopolymer is a possible alternative to petroleum-based plastics. Polybutylene succinate (PBS), polyhydroxyalkanoates (PHA), polylactic acid (PLA), poly(ε-caprolactone) (PCL), cellulose, chitin, and thermoplastic starch are mostly used biopolymers with promising properties. There are challenges too. Properties including brittleness, low thermal stability, low strength, and poor chemical barrier properties are the challenges to replacing plastics material. Reinforcing natural fibers as an alternative to non-biodegradable synthetic fiber with biopolymer matrices improves the properties of the material significantly. Flax, kenaf, jute, ramie, and hemp are a few agro-based fibers that are generally reinforced with biopolymer matrices. These composites are known as green composites. In order to create an interfacial bond between hydrophilic fiber and hydrophobic biopolymer surface modification of natural fiber is needed. There are many physical and chemical methods of surface medication which enhance roughness, wettability as well as hydrophilicity, lowers moisture absorption, improve the interfacial bond, and also enhance the tensile properties of natural fiber. The review is on the classification of biopolymers, natural fibers and their properties as well as the surface modification techniques for plant fibers. Moreover, the fabrication, mechanical and chemical properties including biodegradation of different green composites and the application of green composites, are also discussed here.

Deposition of thin films on basalt fibers surface by atmospheric pressure plasma with different siloxane precursors

In this study, surface modification of basalt fibers (BFs) utilizing atmospheric pressure plasma deposition was carried out. Using this one-step deposition approach, three siloxane precursors with different structures including methyltrimethoxysilane (MTMS), hexamethyldisiloxane (HMDSO), and tetramethoxysilane (TMOS) were deposited on BFs surface, respectively. The physicochemical properties of the thin films from three different siloxane compounds are elucidated. In comparison with MTMS-coated sample, HMDSO-coated and TMOS-coated BFs surfaces feature an improved thermal insulation performance. The results demonstrate that atmospheric pressure plasma deposition is an efficient approach to modify flexible materials surface with improved thermal insulation. Moreover, it provides a reference to decide which precursor type is preferred for certain applications.

Flexural Properties and Failure Mechanisms of Short-Carbon-Fiber-Reinforced Polylactic Acid Composite Modified with MXene and GO.

Recently, short-fiber-reinforced thermoplastic composites (SFRTPCs) have been playing a more and more crucial role in the application of automotive interior materials due to their advantages of low density and environmental resistance properties. However, their relevant mechanical properties need to be optimized. Previous investigations revealed that the surface modification of fibers is useful to improve their mechanical properties. In this work, carbon fiber (CF)-reinforced polylactic acid (PLA) composites modified with MXene and graphene oxide (GO) were prepared by twin-screw extrusion and injection molding methods. Short CF was firstly modified with polyetherimide (PEI), then different weight ratios of MXene-GO (1:1) were subsequently modified on PEI-CF. Finally, the flexural properties and failure mechanisms were analyzed. The results showed that MXene-GO was successfully coated on CF surface, and the flexural strength and modulus of CF-PEI-MXene-GO-reinforced PLA (CF-PEI-MG/PLA) composite were improved compared to that of CF/PLA composite. In addition, the fracture sections of the composites were flat and white, and the fibers bonded well with PLA for CF-PEI-0.1MG/PLA composite compared to CF/PLA composite. The present study could provide a reference for further improving the mechanical performance of PLA-related composites.

Fabrication of highly conductive polyester fabrics using single-wall carbon nanotubes inks for EMI shielding

Abstract We have fabricated single-wall carbon nanotube (SWCNT)-coated electrically conductive polyester fabric using a low-temperature (LT) dip-and-dry method. Polyester fibers are suitable for industrial applications because of their higher heat resistance. We focused on the surface modification of polyester fibers using N,N-dimethyl-formamide solvent and then improved the adhesion of the SWCNT to polyester fibers. The low sheet resistance of 4.3 ± 0.3 Ω sq−1 was achieved while maintaining the intrinsic flexibility and durability of polyester fabrics by using the LT dip-and-dry method. Moreover, we demonstrated the electromagnetic interference (EMI) shielding using the fabricated electrically conductive polyester fabric. The EMI shielding effectiveness (SE) was measured in the frequency ranges of 8–12 GHz using waveguides and a vector network analyzer. The measured SE of the fabricated electrically conductive polyester fabric was about −34 dB and fulfilled the requirement for practical EMI shielding.

Surface modification of Luffa and Maize fibers by using alkali medium

Agricultural biomass is a well-known renewable resource that has a high rate of recycling. Two of them are luffa sponge and corn husk/maize fibers. Luffa sponge may be effectively used to reinforce lightweight composite constructions because of its polypore structure. For this race, maize fiber is also appropriate. Surface modifications for both of the fibers are needed for increasing mechanical strength with higher interfacial bonding with the matrix materials of composite manufacturing. This investigation involved treating both materials with 5 g/L, 10 g/L, and 15 g/L of NaOH in order to describe the alterations occurring on their physio-chemical characteristics. The therapy lasted 60 min and was administered at 90 °C. Following that, acetic acid was used to neutralize the samples. The ASTM D1445 technique was used to measure the bundle fibers' breaking force and elongation, and the ASTM D570 procedures were used in order to determine the water absorption variation % in the treated samples. The FTIR test and SEM examination revealed the contaminants that were eliminated from the surface of Luffa and Maize fibers. The test findings demonstrated improved modification behaviors for the 15 g m/L treated fibers, which had an elongation percentage of 3.02% and an equivalent breaking force of 5.12 kg for the Luffa fiber and 5.72 kg for the maize fiber. Natural contaminants were eliminated as a result of variations in functional group intensity shown in the FTIR pictures. However, SEM pictures showed that the surface smoothed out for samples treated with 15 g per liter of NaOH, which may be the cause of the fiber's brittle interlocking with the matrix components. Moreover, water absorbency rose by over 300% compared to the untreated fibers. In summary, samples treated with 10 g/L NaOH might serve as superior reinforced materials of composite for both types of fibers.