Modification Of Fibers Research Articles

Effect of matrix modification and fiber surface treatment on the properties of basalt fiber reinforced polypropylene composites

With a focus on sustainable natural fiber reinforced polypropylene composites in varied industries like automotive and aerospace, this study investigates the impact of matrix modification and surface treatment of basalt fibers on the thermomechanical properties of basalt fiber reinforced heterophasic polypropylene composites. Polypropylene matrix modification was achieved by adding maleic anhydride grafted polypropylene (PP-g-MA), resulting in composites that exhibited a 133 % improvement in the tensile strength and 256 % improvement in the tensile modulus at 30 % fiber weight compared to neat polypropylene. The short basalt fibers underwent a silane treatment; However, the thermal treatment used to strip the default manufacturer's sizing resulted in a fluffy fibres texture, which led to agglomeration and feeding issues during processing. Although the silane treatment helped establish a better fiber-matrix interphase, no significant improvement in tensile strength was observed. However, the tensile modulus saw a 343 % improvement at 30 % fiber weight as compared to neat polypropylene. Resizing short basalt fibers following fiber recovery at the end-of-life stage of the composite would be challenging due to the fluffy nature of the fibers. Therefore, any fiber treatment should be done at the initial fiber manufacturing stage, and surface treatment at later stages requires detailed study.

UCS and microscopic experimental study of coconut coir fiber-waterborne epoxy resin composite modified calcium sand

To address the issues of high porosity and low strength in calcium sand of artificial islands, this study focuses on improving the calcium sand’s mechanical properties. The effects of WER curing methods and coconut fiber modification on the UCS and microscopic mechanisms of calcium sand are investigated. The results indicate that both fiber incorporation and the increase in WER ratio can enhance the unconfined compressive strength of calcareous sand, with the addition of a certain amount of coconut coir fiber showing a more significant strength increase. The optimal recommended dosage of WER is 15%, which results in an UCS of 1218 kPa, an increase of nearly 4.27 times compared to 9% WER dosage. Coconut coir fiber has good tensile strength that can improve the compressive strength of calcareous sand after curing. The UCS of calcareous sand cured with a fiber content of 0.3% to 0.5% is increased by 1247 kPa to 1792 kPa compared to cured soil with no fiber. The strong binding nature of WER addresses the issue of large porosity in calcareous sand. Together with the penetrating coconut coir fibers, it forms a three-dimensional reticular framework structure, thereby enhancing the compressive performance of the calcareous sand-cured soil mass.

Effect of wettability on the void formation during liquid infusion into fibers

AbstractLiquid composite molding (LCM) is a promising option for low‐cost manufacturing of high‐performance composites compared to traditional prepreg‐autoclave methods. Void formation may be the most significant roadblock to such adaptation of LCM. In this article, the hypothesis that higher wettability, that is, lower contact angles of liquid on solids, would lead to lower void content for LCM is tested. First, a theory that calculates the energy required to form a bubble with varying contact angles is formulated by considering interfacial energy differences of a system with and without it. To experimentally prove this hypothesis, six different carbon fiber reinforcement samples were prepared each with a different fiber surface treatment. The wettability from the surface treatments was evaluated with contact angle measurements based on capillary rise between two fiber yarns. Void formation in situ during infusion was evaluated by a series of 1D infusion experiments using the same six surface modifications. Of the six samples, the reinforcements coated with fluorinated alkane and aminosilane showed the highest wettability and lowest void content, confirming that a lower contact angle can reduce the formation of voids during the infusion process.Highlights Higher wettability was correlated with less bubble (void) formation. Theoretical model and LCM experimental confirmation. Various surface modifications of carbon fibers tested. Potential application: enhancement of properties from LCM manufactured parts.

Optimisation of nitrogen plasma exposure time for surface modification of cotton fibre

Surface modification via plasma treatment is useful in improving textile-based wound dressing functionality. This study was conducted to optimise the nitrogen plasma exposure time and its effect on the cotton surface (CS) properties at a constant nitrogen flow rate of 20 sccm for 5 to 30 min. The optimisation was done by analysing the alteration in morphology, functional group composition, crystallinity phase, electrokinetic potential, and colour of CS as subjected to nitrogen plasma. CS experienced an etching effect due to the presence of microcracks on its surface, with its electrokinetic potential becoming less negative, ranging from -5.51 to –8.05 mV. Then, the nitrogen functional group was detected on CS ranging from 2.9% to 4.5%, with its whiteness index reduced to 8.67% compared to the pristine cotton. As a result, 20 min was selected as the optimum exposure time for surface treatment. An exposure time of 30 min showed an early sign of degradation, which reduced its crystallinity index by 11.1%. Apparently, the CS is activated as exposed to the nitrogen plasma and experiences slight changes in its molecular structure without affecting its bulk properties.

Exploring glass fibers modification conditions and designing lightweight and efficient absorbers based on glass fiber @polypyrrole

Designability of glass fiber (GF) for microwave absorption is frequently neglected in buoyancy matrixes, which overcomes difficulties for their poor polarization loss to realize lightweight and efficient microwave absorption performance. In this study, GF coated with polypyrrole shell (GF@PPy) for multi-layered interface was successfully prepared through surface etching GF and then in-situ growth of PPy. According to the etching process of GF, GF@PPy-t40 (NaOH concentration with 16.67 mol/L, etching time with 40 min) demonstrates the efficient microwave absorption performance. Minimum reflection loss (RLmin) of GF@PPy-t40 (-10.40 dB, 3.0 mm) is 1.5 times that of GF@PPy-w10 (NaOH concentration with 2.78 mol/L) and 1.2 times that of GF@PPy-t60 (etching time with 60 min), which is ascribed to the enhancement of polarized sites caused by surface defects through appropriate etching concentration and time for NaOH. Based on the above etching conditions, we controlled the loading of in-situ polymerized PPy on GF through adjusting the concentration of pyrrole, realizing the impedance matching of 20 wt% GF@PPy in paraffin ring. GF@PPy-c60 (pyrrole concentration as 1.5 g) possesses the best microwave absorption performance, its RLmin is up to −30.40 dB (14.96 GHz, 1.5 mm) and effective absorption bandwidth (EAB) reaches to 4.8 GHz, which is ascribed to its excellent impedance matching. Especially, the density of GF@PPy-c60 can reach to 1.65 g cm−3, which is far below that of commercial GF (2.4–2.7 g cm−3). This modification lighters GF and effectively enhances microwave absorption performance, providing a basis for the radar stealth of GF in the marine environment.

Amphiphilic block and random copolymers: aggregation and hydrophobic modification on metal-free tanned collagen fibers

Hydrophobicity enhancement of metal-free leather, which is crucial for improving its comprehensive performance, can be achieved by using amphiphilic copolymer retanning agents. However, the relationship between the sequential structure and the hydrophobic modification effect of amphiphilic copolymers remains unclear. Herein, an amphiphilic block copolymer was synthesized using stearyl methacrylate and 2-(dimethylamino)ethyl methacrylate via atom transfer radical polymerization, and the corresponding random copolymer with similar monomer compositions and molecular weights was prepared for comparison. The aggregation behavior of block and random copolymers was investigated. DLS and TEM results indicate that the block copolymer exhibits a larger aggregate size than the corresponding random copolymer. Molecular dynamics simulations suggest that the block copolymer aggregate exhibit a thicker hydrophilic shell and more concentrated distribution of cationic DMA block than the random copolymer aggregate. Subsequently, the block and random copolymers were used for the hydrophobic modification of metal-free tanned collagen fibers (CFs). The block copolymer shows superior binding capacity to CFs than the random one because of its larger size and more concentrated charge distribution. Hence, the block copolymer can form a dense and uniform hydrophobic film on the surface of collagen fibrils and endow CFs with higher hydrophobicity than the random one. This work provides theoretical guidance for modulating the hydrophobicity of CFs by tailoring the sequential structure of amphiphilic copolymers, which is expected to inspire the manufacturing of high-performance metal-free leather.Graphical

Quaternization-based graft modification of straw fibers for conditioning the sludge dewatering performance.

Extracellular polymeric substances (EPS) are a critical influencing factor in sludge dewatering. Disrupting such EPS contributes to the release of bound water in sludge, enhancing the sludge dewatering performance. In This study, quaternized straw fibers that are destructive to the EPS structure and components in active sludge were prepared useing heterogeneous free radical graft polymerization. Straw fibers, dimethyl diallyl ammonium chloride (DMDAAC), ammonium persulfate (APS), and acrylamide (AM) were taken as the substrate, grafting monomer, catalyst, and cross-linking agent, respectively.The optimal processing conditions determined for the DMDAAC-based quaternization and graft modification of straw fibers were as follows: reaction temperature of 60 °C, reaction time of 5 h, 0.100 g of catalyst APS dosage per gram of straw, and 3.000 ml of DMDAAC dosage per gram of straw. The optimal processing conditions yielded 1.335 g of modified straw fibers per gram of straw, 33.67% grafting rate, and 31.70% substitution of the quaternary ammonium groups. The capillary suction time (CST) was conditioned from 243.3 ± 22.6 s in the original sludge to 134.5 ± 34.45 s. The specific resistance to filtration (SRF) was reduced from 8.82 ± 0.51 × 1012 m/kg in the original sludge to 4.59 ± 0.23 × 1012 m/kg.

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

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.

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.

Cross-Scale Industrial Manufacturing of Multifunctional Glass Fiber/Epoxy Composite Tubes via a Purposely Modified Filament Winding Production Line.

In the present research work is demonstrated a cross-scale manufacturing approach for the production of multifunctional glass fiber reinforced polymer (GFRP) composite tubes with a purposely redesigned filament winding process. Up until now, limited studies have been reported towards the multiscale reinforcement direction of continuous fibers for the manufacturing of hierarchical composites at the industrial level. This study involved the development of two different multi-walled carbon nanotube (MWCNT) aqueous-based inks, which were employed for the modification of commercial glass fiber (GF) reinforcing tows via a bath coating unit in a pilot production line. The obtained multifunctional GFRP tubes presented a variety of characteristics in relation to their final mechanical, hydrothermal aging, electrical, thermal and thermoelectric properties. Results revealed that the two individual systems exhibited pronounced differences both in crushing behavior and durability performance. Interestingly, for lateral compression the MWCNT coatings comprising a polymeric dispersant minorly affected the mechanical response of the produced tubes. The crashworthiness indicators of the multifunctional tubes displayed a slight 5% variation to the respective reference values, combined with a more ductile behavior. Moreover, regarding the bulk electrical and thermal conductivity values, as well as the Seebeck coefficient factor, the corresponding tubes displayed a variance of 233% and 19% and an opposite semi-conducting sign denoting a p- and n-type character, respectively.

Silane-modified high-yield lignocellulosic fibers as reinforcement of polylactic acid: Enhancement of interfacial adhesion for high-performance biocomposites

This study investigates the enhancement of PLA-based biocomposites using high-yield mechanical stone groundwood (SGW) pulp, with a focus on reinforcing fiber-matrix interactions through silane-coupling fiber modification. Different fractions of SGW (20 and 30 wt%) and (3-glycidyloxypropyl)trimethoxysilane (GPS) as a coupling agent (3, 5, 7, and 10 wt%) were incorporated into the PLA matrix. Thermo-mechanical properties including melt flow index, melt rheology, tensile strength, and Young’s modulus were evaluated, along with thermal degradation behavior via TGA and DSC. Non-modified and partially modified SGW fractions (20 and 30 wt%) improved PLA-SGW interface, resulting in increased tensile strength (14 % and 27 % respectively). Biocomposites with 30 wt% SGW modified with 5 and 7 wt% GPS exhibited the highest tensile strength improvement, along with the rest of the properties, attributed to GPS influence on melt flow index and processability. The obtained biocomposites showcased properties comparable to commodity polypropylene composites.

Functional modification of softwood fiber and its application in natural fiber-based sound-absorbing composite

Natural fiber-based sound-absorbing materials have received more and more attention due to the increasingly severe noise pollution. However, the current natural fibers’ sound-absorbing materials often have poor flame-retardant performance and degradability, which limits their further application. In this study, flame-retardant cellulose fiber (FRCF) was prepared by modifying softwood fiber, and a kind of fiber-based sound-absorbing material, natural fiber-based sound-absorbing composite (NFSC), was prepared by replacing glass fiber with FRCF. The results show that the synthesis of FRCF is successful, and the functional groups containing phosphorus and nitrogen introduced into the cellulose side chain can significantly improve the thermal stability of softwood fiber. FRCF is able to bestow initial flame-retardant capability on the NFSC, allowing NFSC to get the V-1 level in vertical burning test with fewer flame retardants, and the limiting oxygen index (LOI) of NFSC can reach 28.5 %. The NFSC with FRCF instead of glass fiber also has better sound absorption performance; its maximum sound absorption coefficient reaches 0.90, and its noise reduction coefficient (NRC) reaches 0.45. This work is expected to provide inspiration for the design and preparation of environmentally friendly natural fiber-based sound-absorbing materials.

In-situ synthesis of bimetallic Co/Zn-ZIF on the graphite-felt for electrocatalytic degradation of pharmaceutical pollutants

In the electro-Fenton process, one of the important challenges is to adjust the pH of the environment in the acidic region so that the system's performance is not affected by side reactions. In this case, it will be necessary to neutralize the solution after the process. One of the solutions is to use a heterogeneous catalyst to widen the pH range. However, recovering the used catalyst itself can be another challenge. Modifying the electrode using electroactive materials can answer both of these challenges. This work modified the bare graphite-felt (GF) electrode using zeolitic imidazolate frameworks (ZIF)-derived carbon material doped with Co and Zn through a rapid, room-temperature, and water-based synthesis method. Various analyses, including XRD, SEM, XPS, and LSV, confirmed the proper modification of bare GF carbon fibers. The modified Co/Zn-N-C@GF electrode showed good performance in removing rifampicin (RFP) during the electro-Fenton process, so about 90 % of the pollutant was removed within 30 min without adding a homo-/heterogeneous catalyst. Optimum conditions for this process were 1.0 V for applied voltage, 40 mg/L for initial concentration of RFP, and 5.6 for pH. Also, LC-MS analysis was performed to confirm the degradation of RFP and investigate its degradation pathway.

Surface modification of synthetic polymer fibers

Surface modification of synthetic polymer fibers

Sugarcane Bagasse: Challenges and Opportunities for Waste Recycling

Sugarcane has primarily been used for sugar and ethanol production. It creates large quantities of residual lignocellulosic biomass such as sugarcane bagasse, leaves, tops, and vinasse. Biomass is a sustainable prospect for biorefineries aiming to optimize production processes. We detail recent research developments in recycling sugarcane, including energy generation and pyrolysis to obtain biofuels, for example. To produce biochar, the energy cost of operating at high temperatures and large-scale production remain as obstacles. The energy generation prospects can be enhanced by pellet production; however, it requires an improvement in quality control for long-term storage or long-distance transportation. In civil construction, the materials still need to prove their long-term efficiency and reliability. Related to adsorbent materials, the use of sugarcane bagasse has the advantage of being low-cost and environmentally friendly. Nevertheless, the extraction, functionalization, and modification of cellulose fibers, to improve their adsorption properties or even mode of operation, still challenges. The synthesis of nanostructures is still lacking high yields and the ability to scale up. Finally, controlling dispersion and orientation and avoiding fiber agglomeration could improve the mechanical response of composites using sugarcane bagasse. The different possibilities for using sugarcane and its residues reinforce the importance of this material for the industry and the global economy. Thus, the present work addresses current challenges and perspectives of different industrial processes involving sugarcane aiming to support future research on waste-derived subjects.

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.

Strength reinforcement of coal fly ash based non-sintered lightweight aggregates by autoclave curing and H2O2-modified basalt fiber addition

Coal fly ash, an industrial solid waste, occupies land and pollutes the environment in long-term stockpiling. Utilization of coal fly ash to produce non-sintered lightweight aggregates is a simple and cheap process with low energy consumption. However, it is still a challenge to produce coal fly ash based non-sintered lightweight aggregates with high mechanical and physical properties. In this work, high strength coal fly ash based non-sintered lightweight aggregates with low initial Ca/Si ratio were produced by autoclave curing and 1 h H2O2-modified basalt fiber addition. The cylinder compressive strength, 1 h water absorption, the bulk density and apparent density of the produced aggregates are 15.52 MPa, 4.85 %, 1089.83 kg/m3 and 1762.43 kg/m3 respectively. By analyzing the phase composition, microstructure and pore structure of the produced aggregates by XRD, SEM, FT-IR and MIP, it suggested that honeycomb-like C-A-S-H gel was formed and filled the pores in the aggregate matrix. Shown in the 3D profiles, a highly rough surface was formed on the basalt fiber after 1 h H2O2-modification. The rough surface provided as anchoring points for the interaction between the aggregate matrix and the fiber. Autoclave curing and basalt fiber modification synergistically improved the mechanical and physical properties of coal fly ash based non-sintered lightweight aggregates through “chemical filling-physical occupancy”.

Amazon açaí fibre–Portland cement compatibility: a challenge to produce cement-bonded fibreboards?

The açaí waste from the Amazon contains short fibres that show potential for reinforcing cement-bonded fibreboards (CBFBs), although their compatibility with the cement matrix is still unknown. The aim of this work was to characterise raw and pretreated açaí fibres and analyse their compatibility with Portland cement by different techniques, alongside developing a CBFB. The fibres were subjected to thermal (180, 200 and 220°C), cold and hot water, alkaline (NaOH) and bleaching (NaOH–H2O2) pretreatments. The chemical and water pretreatments raised the fibre crystalline indexes (28–57%). The chemical pretreatments individualised the fibre bundles and removed hemicelluloses. Alkali-pretreated and raw fibres had the highest (96%) and lowest (65%) cement compatibility indexes. Portlandite and ettringite appeared after 24 h for most pastes, but were delayed for raw and 220°C-pretreated fibres. In contrast, only the raw fibre specimens reached the required compression strength of 34 MPa after 28 days; hence, they were chosen to produce a CBFB. The boards showed proper thickness swelling (1.4%), but low bending strength (modulus of elasticity = 647.8 MPa; modulus of rupture = 1.9 MPa). Overall, the fibre modifications improved the compatibility with cement, but not the composite's mechanical strength. Açaí-fibre CBFB is a promising building material, but future studies must overcome its poor mechanical performance.

Carboxylic acid modulated in situ growth of Zr-based MOFs on carboxylated cotton fabrics for removal of Cr(VI) from aqueous solutions

In this paper, carboxylated cotton fabric (CF-Ph-COOH) were obtained as active substrate by diazonium radical polymerization modification of cotton fibers. Then the MOF fabric composites were prepared by in situ growth of metal zirconium ions (Zr) and organic ligands on the surface of carboxylated cotton fabrics under carboxylic acid modifier. MOF fabric composites with controllable morphologies structures were achieved by regulating organic ligands, reaction time the type and dosage of regulator (formic acid and acetic acid). The prepared acetic acid regulated MOF fabric composites were designated as CF-HAc1-UiO-66, CF-HAc2-UiO-66, CF-HAc1-UiO-66-NH2, and CF-HAc2-UiO-66-NH2, respectively, and the formic acid regulated as CF-FA-UiO-66 and CF-FA-UiO-66-NH2. The fabricated carboxylic acid modulated MOF fabric composites were well characterized using SEM, TGA, XRD, FTIR, and XPS spectra. The adsorption experiment results show that carboxylic acid modulated Zr based MOF fabric composites can serve as adsorbent for effective removal of Cr(VI) from water, in which the CF-FA-UiO-66-NH2 was prepared under the ratio of ZrCl4 and BDC-NH2 is 1.006 and with 5.47 M formic acid regulator exhibits that the optimal adsorption efficiency and the removal efficiency is 79.5 %. In addition, the adsorption of Cr(VI) in water by CFA-UiO-66-NH2 showed a quasi-secondary kinetic model following the Langmuir adsorption model, showing a a typical of chemisorption. What’s more, the Cr(VI) removal efficiency and saturated adsorption capacity of CF-FA-UiO-66-NH2 was up to 80 % and 318.85 mg/g, respectively. The prepared CF-FA-UiO-66-NH2 MOF fabric composite was recyclable for removal of Cr(VI), and could be used as the potential adsorbent membrane for waste water treatment.