Neat Fibers Research Articles

Improving physical, mechanical and interfacial properties of glass fiber composites using modified resin system with amine‐functionalized and silanized graphene nanoparticles

AbstractAmine functionalization and silanization of graphene nanoparticles (GNPs) facilitate better interlocking interaction with the polymer matrix, leading to the development of high‐performance laminated composites for structural applications. Hence, in this article, the effect of amine functionalization and silanization of GNPs on the physical, mechanical, interfacial, and nano‐indentation mechanisms of functionalized GNPs (F‐GNPs) infused glass fiber reinforced bio‐epoxy polymer composites (GFRPCs) is investigated. To this end, different weight fractions of GNPs (0.5%, 1.0%, & 1.5%) with various oxidation times (24, 48, 72 h) have been considered for assessment. The interfacial interaction of normal and functionalized GNPs has been assessed through field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). The homogeneous dispersion, crystallization, and exfoliation of GNPs have been analyzed with Fourier transform infrared (FTIR), Raman spectrometer, x‐ray diffraction (XRD), and x‐ray photoelectron spectroscopy (XPS). The results of FESEM and AFM revealed successful exfoliation of GNPs occurring at 48 h of oxidation. The characterization, such as FTIR, XRD, and XPS analyses, revealed that the functionalized GNPs provided better dispersion and interfacial interaction with the epoxy matrix. Further, the inclusion of functionalized GNPs improved the tensile strength, flexural strength, and interlaminar shear stress by 127.44%, 132.01%, and 23.79%, respectively, compared to neat glass fiber composites. In addition, a significant enhancement in the interfacial transverse properties of hybrid GFRPCs was achieved.Highlights The effect of functionalization and silanization of GNPs on GFRPCs is investigated. Physical, interfacial and mechanical properties are studied. Oxidation has been done at oxidation times of 24, 48, and 72 h. Interfacial interaction of normal and functionalized GNPs is compared. Enhanced properties obtained with the functionalization of GNPs and silanization.

An experimental investigation into crashworthiness of filament wound intra-yarn hybrid glass/jute epoxy composites tubes under quasi-static axial and lateral compression

An experimental investigation into crashworthiness of filament wound intra-yarn hybrid glass/jute epoxy composites tubes under quasi-static axial and lateral compression

Development of PHBV electrospun fibers containing a borate bioactive glass doped with Co, Cu, and Zn for wound dressings.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers embedded with borate glasses of 45B5 composition doped with Co2+, Cu2+, and Zn2 +(46.1 B₂O₃26.9-X CaO24.4 Na₂O2.6 P₂O₅, X CoO/CuO/ZnO mol % (X = 0-5)) were produced by electrospinning for wound healing applications. Prior to their addition, the glasses exhibited two broad halos typical of a vitreous borate network, which were mainly composed of ring-type metaborate structural units. The particle distribution in the PHBV nanofibers embedded with 45B5 borate bioactive glasses is present in isolated and agglomerated states, being partially coated by a polymeric layer-except for the cobalt-doped glass, which resulted in a successful encapsulation with 100% embedding efficiency. The incorporation of the glasses reduced the PHBV crystallinity degree and its decomposition temperature, as well as its mechanical properties, including Young's modulus, tensile strength, and elongation at break. The neat PHBV fibers and those containing the cobalt-doped glasses demonstrated great cytocompatibility with human keratinocytes (HaCat), as suggested by the high cell viability after 7 days of exposure. Further studies are needed to fully understand the wound healing potential of these fibers, but our results significantly contribute to the area.

Structure and properties of chlorogenic acid-loaded polylactide fiber prepared by melt spinning

Structure and properties of chlorogenic acid-loaded polylactide fiber prepared by melt spinning

Superior heat‐resistant polylactide/poly(butylene succinate) blend fibers via in‐situ reactive compatibilization

AbstractBlending poly(butylene succinate) (PBS) with polylactide (PLLA) has proven effective in improving heat resistance of PLLA fibers. Unfortunately, it remains challenging to maintain good spinnability for PLLA/PBS blends with high content of PBS with which further improved heat resistance could be anticipated. In this study, reactive melt‐extrusion was devised to in‐situ generate PLLA‐PBS copolymers by introducing zinc acetate as a transesterification catalyst into PLLA/PBS blends. The compatibility between the PLLA and PBS phases was greatly improved by the formation of PLLA‐PBS copolymers, resulting in excellent melt‐spinnability even for the PLLA/PBS blends with high PBS content up to 20 wt%. In addition, an increase in crystallinity of PLLA was achieved in PLLA/PBS blend fibers, thanks to the enhanced compatibility. More importantly, the presence of PBS nuclei retarded the molecular orientation of the amorphous PLLA phase, consistent with the effective results from the relaxation heat‐setting treatment. These led to an exceptionally improved heat resistance of the PLLA/PBS blend fibers. As an encouraging result, the boiling water shrinkage was significantly reduced from ca. 20% for neat PLLA fibers to 3.7% for the PLLA/PBS blend fibers with 20 wt% PBS content. These findings may open up a facile and effective route to develop PLLA/PBS blend fibers showing sound spinnability, greatly improved heat resistance and softness.

Tribological performance of 3D printed neat and carbon fiber reinforced PEEK composites

This work investigates the tribological behavior of neat and carbon fiber-reinforced polyether-ether-ketone (PEEK) materials processed using the fused filament fabrication (FFF) technique. The reciprocating sliding behavior of printed polymers against stainless steel (SS) under dry and water-lubricated conditions was studied. The running-in behavior and evolution of friction were dependent on the material combination and sliding conditions. PEEK reinforced with 10 wt% carbon fibers was optimal considering tribological performance. Neat PEEK exhibited a combination of abrasive and adhesive wear mechanisms, while composites primarily showed fiber-matrix debonding and delamination during sliding. The outcome of this work has significance in improving the processing design of PEEK-based materials in extrusion-based 3D printing for tribological applications.

Novel electrospun nanofibers based on gelatin/oxidized xanthan gum containing propolis reinforced by Schiff base cross-linking for food packaging.

Novel electrospun nanofibers based on gelatin/oxidized xanthan gum containing propolis reinforced by Schiff base cross-linking for food packaging.

Single-Solvent Fractionation and Electro-Spinning Neat Softwood Kraft Lignin.

This paper reports on the production of electro-spun nanofibers from softwood Kraft lignin without the need for polymer blending and/or chemical modification. Commercially available softwood Kraft lignin was fractionated using acetone. The acetone-soluble lignin (AcSL) had an ash content of 0.06 wt %, a weight average molecular weight of 4250 g·mol-1 along with the polydispersity index of 1.73. The corresponding values for as-received lignin (ARL) were 1.20 wt %, 6000 g·mol-1, and 2.22, respectively. The AcS was dissolved in a binary solvent consisting of acetone, and dimethyl sulfoxide (2:1, v/v) was selected for dissolving the AcSL. Conventional and custom-designed grounded electrode configurations were used to produce electro-spun neat lignin fibers that were randomly oriented or highly aligned, respectively. The diameter of the electro-spun fibers ranged from 1.12 to 1.46 μm. After vacuum drying at 140 °C for 6 h to remove the solvents and oxidation at 250 °C, the fibers were carbonized at 1000, 1200, and 1500 °C for 1 h. The carbonized fibers were unfused and void-free with an average diameter of 500 nm. Raman spectroscopy, scanning electron microscopy, and image analysis were used to characterize the carbonized fibers.

Inorganic fullerene-like tungsten disulfide/waterborne polyurethane reinforced Spectra® composites with improved mechanical properties and tensile energy absorption

Inorganic fullerene-like tungsten disulfide/waterborne polyurethane reinforced Spectra® composites with improved mechanical properties and tensile energy absorption

Fabrication and Characterization of High Performance PVDF-based flexible piezoelectric nanogenerators using PMN-xPT (x:30, 32.5, and 35) particles

Fabrication and Characterization of High Performance PVDF-based flexible piezoelectric nanogenerators using PMN-xPT (x:30, 32.5, and 35) particles

Polylactide/poly[(R)‐3‐hydroxybutyrate] (PHB) blend fibers with superior heat‐resistance: Effect ofPHBon crystallization

AbstractBlending low content of poly[(R)‐3‐hydroxybutyrate‐co‐4‐hydroxybutyrate] (P34HB ≤8 wt %) with poly(L‐lactide) (PLLA) has proven effective in enhancing heat resistance of PLLA fibers. Unfortunately, the enhancement is relatively limited with boiling water shrinkage of PLLA/P34HB blend fibers reduced to 9.9% at most. In this study, a series of PLLA/poly[(R)‐3‐hydroxybutyrate] (PHB) blend fibers with low PHB content (≤8 wt %) was prepared with sound spinnability. Surprisingly, the PLLA/PHB blend fibers showed much lower boiling water shrinkage than the PLLA/P34HB blend fibers with the same blend ratio. In particular, the boiling water shrinkage was dropped from ca. 80% for neat PLLA fibers to 9.9% for the PLA/P34HB blend fibers and further to 3.8% for the PLA/PHB blend fibers with 8 wt % P34HB or PHB added. Such an exceptionally improved heat resistance of the PLLA/PHB blend fibers could be closely related to an increase in crystallinity (Xc,PLLA) of the PLLA phase. Specifically, the mobility of the PLLA segments was promoted in the presence of PHB, along with notably improved orientation of the PLLA phase in the PLLA/PHB blend fibers. More importantly, investigation on crystallization behaviors revealed that the PHB phase served as an effective nucleating agent to accelerate the overall crystallization of PLLA. By contrast, the P34HB phase only acted as spherulite growth‐accelerating and/or nucleation‐assisting agents. These findings help provide a facile and effective strategy to improve heat resistance of PLLA fibers more significantly.

Correlation between Morphology, Mechanical Properties and Microdeformation Behavior of Electrospun Scaffolds Based on a Biobased Polymer Blend and Biogenic Nano-Hydroxyapatite

Correlation between Morphology, Mechanical Properties and Microdeformation Behavior of Electrospun Scaffolds Based on a Biobased Polymer Blend and Biogenic Nano-Hydroxyapatite

Piezoresistive Fibers with Large Working Factors for Strain Sensing Applications.

Piezoresistive fibers with large working factors remain of great interest for strain sensing applications involving large strains, yet difficult to achieve. Here, we produced strain-sensitive fibers with large working factors by dip-coating nanocomposite piezoresistive inks on surface-modified polyether block amide (PEBA) fibers. Surface modification of neat PEBA fibers was carried out with polydopamine (PDA) while nanocomposite conductive inks consisted of styrene-ethylene-butylene-styrene (SEBS) elastomer and carbon black (CB). As such, the deposition of piezoresistive coatings was enabled through nonconventional hydrogen-bonding interactions. The resultant fibers demonstrated well-defined piezoresistive linear relationships, which increased with CB filler loading in SEBS. In addition, gauge factors decreased with increasing CB mass fractions from ∼15 to ∼7. Furthermore, we used the fatigue theory to predict the endurance limit (Ce) of our fibers toward resistance signal stability. Such a piezoresistive performance allowed us to explore the application of our fibers as strain sensors for monitoring the movement of finger joints.

Revisiting the Contribution of Additives to the Long-Term Mechanical Stability and Hydrolytic Resistance of Highly Crystalline Polylactide Fibers

Additives are widely used to improve the processability, toughness, and hydrolytic resistance of poly(lactic acid) (PLA)-based materials. This study compares neat PLA fibers and fibers made from PLA blends with either poly(butylene succinate) (PBS) as a plasticizer or poly(d-lactic acid) (PDLA) as a nucleating agent. The fibers have been characterized with regard to their physical and structural properties after fabrication as well as after artificial aging at elevated temperature and humidity conditions. All samples have been fabricated using industrial melt-spinning equipment, resulting in a high crystallinity of about XC = 80% and a good initial toughness. Long-term relaxation behavior has been assessed with a self-developed lifetime prediction model, which is successfully verified for semicrystalline blended fibers. Despite slight improvement of the fiber elasticity and ductility, both types of blended fibers demonstrated a reduced hydrolytic resistance. These results suggest a design strategy for neat durable PLA fibers through processing-induced high crystallinity and orientation, which provide improved hydrolytic stability while preserving tough mechanical performance.

Processing and tribological behaviour of carbon fiber reinforced polylactic acid composites

Thermoplastic composites are acquiring more importance in various tribological applications due to their self-lubricity, low melting, and ease of fabrication. In this research article, processing via fused deposition modelling and dry sliding wear behaviour of neat and short carbon fiber reinforced polylactic acid composites have been investigated. A series of wear tests using a pin-on-disc wear apparatus was carried out by varying tribo-parameters namely applied load (10, 20, and 30 N), sliding velocity (0.5, 1.0, and 1.5 m/s), and sliding distance (1000, 2000, and 3000 m) following the response surface methodology. Analysis of variance was performed for optimizing the operating parameters with respect to minimum specific wear rate. The experimental outcomes showed decrease in specific wear rate of polylactic acid composites by 70 % in comparison to neat polylactic acid, due to reinforcement of short carbon fibers. Worn surface morphology of neat polylactic acid and carbon fiber reinforced polylactic acid show fine groves in the sliding direction, thinning of fibers and net work of microcracks and few pull-out of fibres from the matrix material.

Evaluation of tensile fatigue behavior of carbon fiber reinforced polymer modified by single‐wall carbon nanotubes

AbstractThe fatigue behavior of epoxy‐based carbon fiber reinforced composite with additional modification by single‐wall carbon nanotubes (SWCNT) has been investigated. Neat carbon fiber reinforced polymer and four types of specimens with different SWCNT weight content were tested: 0.1%, 0.2%, 0.3%, and 0.5 wt%. To evaluate damage accumulation and fatigue behavior of open‐hole specimens, digital image correlation was implemented. The strain fields were obtained at predefined lifetimes and the stiffness evolution during cyclic tension‐tension loading was analyzed. Composites were studied using scanning electron microscopy to reveal peculiarities of structure, damage, and fracture. Achieved improvement of fatigue properties was discussed in terms of enhanced interlaminar strength and matrix stiffness. The addition of 0.2% of CNT increases the ultimate tensile strength by 7.3%, failure strain by 7.5%, while the elastic modulus is nearly unaffected. The fatigue durability is increased by 3.4 times.

Effects of extreme low temperatures on the impact behavior of boron nitride nanofillers added carbon fiber/epoxy composite tubes

This study aims to investigate the low-velocity impact response of boron nitride nanoparticles (BNNPs) added carbon fiber reinforced pipes (CFRPs) at various temperature values. Carbon fiber/epoxy composite specimens with (±55°)3 winding angles were manufactured with the filament winding method. Low-velocity impact tests were performed with a 15 J energy level at five different temperatures between −196°C and 23°C ranges to understand the cryogenic environment effect on BNNP added carbon fiber reinforced tubes and neat carbon fiber reinforced tubes. The force-displacement and contact force-time graphs were attained in consequence of low-velocity impact tests. The damage areas, their size and characteristics were scrutinized both visually and with the aid of a Microscope. The test results showed that when ambiance temperatures decreased, the damage areas considerably increased both filled with BNNP and without BNNP filament wound carbon fiber reinforced tubes.

Study on the dispersibility of modified basalt fiber and its influence on the mechanical properties of concrete

Study on the dispersibility of modified basalt fiber and its influence on the mechanical properties of concrete

Biaxial electrospun nanofibers based on chitosan-poly (vinyl alcohol) and poly (Ɛ-caprolactone) modified with CeAlO3 nanoparticles as potential wound dressing materials

Biaxial electrospun nanofibers based on chitosan-poly (vinyl alcohol) and poly (Ɛ-caprolactone) modified with CeAlO3 nanoparticles as potential wound dressing materials

Low density polyethylene composites based on flax fibers modified by a combination of coupling agent

AbstractThis investigation proposes a natural fiber surface modification approach based on the use of a system of coupling agents (CAs) to improve the mechanical properties of polymer composites made of flax fibers and low‐density polyethylene. This system combines the coating of the NaOH treated (mercerized) flax fibers by a CA (Epolene C18 [M‐C18]) in a solution under moderated heat (70°C–80°C), followed by the addition of 1% or 3% wt. of another CA (Epolene E43 [M‐E43]) during the injection molding. The comparison between the solution modified and the neat and mercerized flax fibers using scanning electron micrograph (SEM), thermogravimetric analysis (TGA), and density underscored some differences ascribed to the presence of M‐C18 onto the modified fibers. The mechanical properties showed that the combination of solution modification and direct introduction during the injection‐molding step of 1% of M‐E43 was efficient as the corresponding composites exhibited an improvement of 9.1%, 15.9%, and 11.1% of his tensile, flexural, and impact strengths respectively compared to the neat fiber composite. Due to their good impact and flexural strengths, these composites can be suitable for automotive parts such as keyboard.