Fiber-reinforced Poly Research Articles

Rice husk/glass fiber-reinforced poly(lactic acid) hybrid composites: rheological and dynamic mechanical study

Rice husk/glass fiber-reinforced poly(lactic acid) hybrid composites: rheological and dynamic mechanical study

Cell viability assessment and physicomechanical characterization of Juglans regia leaf fiber-reinforced poly(hydroxybutyrate) films for biomedical uses

Cell viability assessment and physicomechanical characterization of Juglans regia leaf fiber-reinforced poly(hydroxybutyrate) films for biomedical uses

Reclaimed lignosulfonate-modified bamboo fibers prepared via layer-by-layer self-assembly to reinforce poly(3-hydroxybutyrate) biocomposite

Fiber-reinforced poly(3-hydroxybutyrate) (PHB) biocomposites have been increasingly applied in various fields, such as building structures, interior decorations, and product packaging, due to their high strength to weight ratios, low thermal conductivities, low carbon footprints, and biodegradabilities. However, poor compatibility between the hydrophilic natural fibers and the thermoplastic biocomposites limits their mechanical strengths. This work proposes a method based on layer-by-layer self-assembly (LbL) to improve the interfacial compatibility between the PHB and bamboo fibers (BFs). Sodium lignosulfonate (SL) derived from pulp and paper industry waste was used as the raw material. Then, long carbon chains were introduced into the SL via the Mannich reaction. A hydrophobic self-assembled multilayer structure (SMS) was constructed on the surfaces of the BFs. The preparation process was environmentally friendly, controllable and simple. The mechanical properties were improved by the modifications, including the tensile strength (44%), flexural strength (13%), and impact strength (41%). The thermal properties of the fiber-reinforced biocomposites were also enhanced. This study presents a novel strategy for high-value utilization of industrial byproducts and the enhancement of biocomposite interfacial compatibility.

Compression Molding of Hybrid Continuous and Discontinuous Fiber Reinforced Thermoplastics for Enhancing Strength Characteristics

Compression molding with long discontinuous fiber-reinforced thermoplastics enables replacing traditionally machined metallic components with geometrical complexity and with reductions in weight and potential enhancements in structural characteristics like durability, fatigue, and serviceability. Fiber length is critical in fiber-reinforced composites. While long continuous fibers limit the geometrical complexity that can be fabricated but provide exceptional mechanical properties, discontinuous fibers provide manufacturing flexibility but with a penalty in strength. This work demonstrates enhancement in strength and reduction in strength variability achieved by compression molding of long discontinuous fiber platelets and continuous fiber preforms. This approach was demonstrated for an overhead bin pin bracket geometry. Continuous fiber preforms were manufactured with 60% by volume of carbon fiber-reinforced Poly Ether Ketone Ketone (PEKK) using the 9T Labs continuous fiber Additive Fusion Technology (AFT). Similarly, fiber platelets with 60% by volume of carbon fiber reinforced PEKK were utilized. Continuous fiber preforms were designed considering both the concurrent flow of continuous and discontinuous fibers with the desired mesostructure of continuous and discontinuous fibers. The results presented in this work showed an increase of 99.6% in the load at the onset of damage by reinforcing the pin bracket with about 17% by weight of continuous fiber preforms. Similarly, the coefficient of variance of the load at the onset of failure decreased by 46%. Finally, reinforcing the pin bracket with continuous fiber preforms not only enhanced the strength characteristics but also decreased the variability in strength characteristics.

Cellulose-based bioabsorbable and antibiotic coated surgical staple with bioinspired design for efficient wound closure

The quest to design a flawless wound closure system began long ago and is still underway. Introducing surgical staples is one of the most significant breakthroughs in this effort. In this work, we developed a biodegradable surgical staple to meet the optimal wound closure system criteria and other clinical requirements, such as radiography compatibility and secondary infection prevention. To meet these requirements, a naturally derived cellulose acetate (CA) fiber-reinforced poly-(l-lactic acid) (PLLA) composite was synthesized, and its physicochemical properties were determined using several characterizations such as Fourier-transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and Universal testing machine (UTM), etc. Taking cues from the Mantis's foreleg, a novel staple design was implemented and verified using Finite Element Analysis (FEA). The CA + PLLA staples were fabricated using melt-casted/3D-printing processes. The staples exhibited excellent biodegradation in both wound and physiological microenvironments with sufficient puncturing strength and later closed the wound's edges mechanically. In addition, the CA + PLLA staples also exhibit metal-like ductility properties to withstand horizontal skin tensions during the healing process. Further, the staples are coated with an antibiotic to combat infections effectively to provide better healing.

Inorganic Fillers and Their Effects on the Properties of Flax/PLA Composites after UV Degradation.

The present investigation seeks to assess the impact of fillers on the mechanical characteristics of entirely biodegradable composites, introducing an advanced solution to fulfil long-term durability demands within point-of-purchase (POP) industries. The inclusion of calcium carbonate (CaCO3) fillers on the various properties of the flax fibre-reinforced composites, after accelerated irradiation in an ultraviolet (UV) radiation exposure has been investigated in the present study. Different types of flax fibre-reinforced poly lactic acid (PLA) biocomposites (with and without filler) were fabricated. The mechanical (tensile and flexural), and physical properties of the specimens were assessed after 500 h of exposure to accelerated UV irradiation of 0.48 W/m2 at 50 °C and were compared with those of the unexposed specimens. The results indicate that the presence of the inorganic filler significantly improved the performance of the biocomposites compared to the unfilled biocomposites after UV exposure. After adding 20% of fillers, the tensile strength was increased by 2% after UV degradation, whereas the biocomposite without filler lost 18% of its strength after UV exposure. This can be attributed to the change in the photo-degradation of the PLA due to the presence of the CaCO3 filler, which acts as a safeguard against UV light penetration by creating a protective barrier. The scanning electron microscopy (SEM) images of the degraded specimen surface show substantial difference in the surface topography of the composites with and without fillers.

Design and fabrication of high-performance 3D printed continuous flax fibre/PLA composites

The mechanical properties of 3D-printed continuous plant fibre-reinforced poly(lactic) acid (PLA) composites are insufficient due to the low fibre volume fraction (∼30 %). Further increase of fibre volume fraction of composites by reducing the line width may result in a composite with low fibre impregnation degree or the clogging of printer nozzle because of the twisted nature and uneven diameter of plant yarns, which also degrades the mechanical properties. This study proposed a method to obtain 3D printed continuous flax fibre reinforced composites (CFFRCs) with a high fibre volume fraction and excellent mechanical performance by statistical analysis of the dimensions of flax fibre yarns as well as surface modification. The CFFRCs were printed by a fibre prepreg-based 3D printing method, and an in-situ impregnation method was also used to prepare CFFRCs for comparison. The results showed that the CFFRCs by the fibre prepreg method had a fibre volume fraction of 44.1 % and a void content of ∼1.9 % due to the high impregnation degree. Correspondingly, the tensile modulus and strength of the CFFRCs were the highest among the existing reported values of the composites made by 3D printing and even greater than those of the CFFRCs with a fibre volume fraction of ∼51.4 % prepared by the in-situ impregnation method.

New Strategy for Improvement of Interfacial Interactions between Poly(arylene sulfide sulfone) and Carbon Fiber by Grafting Polymeric Chains via Thiol-Ene Click Chemistry.

A simple and efficient strategy for enhancing the interfacial interaction in carbon fiber-reinforced poly(arylene sulfide sulfone) (CF/PASS) composites by grafting polymeric chains via thiol-ene click chemistry is reported here. Simultaneously, three thiol compounds and carbon nanotubes were grafted on CFs to explore the reaction between the CF and thiol groups. X-ray photoelectron spectroscopy, Raman spectroscopy, and normalized temperature-dependent IR spectroscopy results confirm the successful grafting of three thiol compounds, carbon nanotubes, and polymer chains. Similarly, obvious changes on the CF surface can be seen before and after modification via scanning electron microscopy, such as grafted nanotubes and polymeric resin, and the increase in the modulus gradient and interfacial thickness of CF/PASS can be clearly seen via atomic force microscopy. All the results of micro and macro tests on mechanical properties indicate that connecting low molecular weight thiol-terminated PASS (HS-LPASS) onto CFs enhances the interfacial property and mechanical performance of CF/PASS to a greater extent. The interfacial shear strength, interlaminar shear strength, and tensile strength of CF@HS-LPASS-reinforced PASS (CF@HS-LPASS/PASS) increase significantly by 38.5, 43.6, and 24.4%, respectively. All the results demonstrate that thiol-ene click reactions can be used for CF modification; furthermore, in the presence of external stress, the grafted polymeric interphase can act as a "bridge layer" to improve the stress transfer efficiency.

Development of Bio-based Polybenzoxazine Composite Post : Effect of Glass Fiber Content on Mechanical Properties and Fracture Behaviors

This work aims to develop a novel composite post based on bio-based polybenzoxazine reinforced with glass fiber. The bio-based polybenzoxazine (poly(V-fa)) derived from vanillin, furfurylamine and paraformaldehyde, was prepared as polymer matrix in this study. Mechanical property and thermal property influenced by glass fiber contents were evaluated. The numerical simulation was also used to study the response to external applied load of tooth restored with glass fiber-reinforced poly(V-fa) composite posts by finite element analysis. From the results, not only the flexural properties, i.e. flexural strength and flexural modulus, were substantially improved up to 460 MPa and 25.6 GPa, respectively, but thermal properties, i.e. glass transition temperature (Tg) and degradation temperature at 5wt% loss (Td5), of the composites were also enhanced with the reinforcement of glass fiber contents. Furthermore, the restoration of the developed glass fiber-reinforced poly(V-fa) composite post in term of the maximum von Mises stress and deformation areas was predicted via ANSYS program. The experimental and numerical results revealed that the bio-based polybenzoxazine composite reinforced with glass fiber have highly potential to be used as composite posts.

Biocomposite panels with unidirectional core stiffeners − 3-point bending properties and considerations on 3D printing and extrusion as a manufacturing method

Sandwich panels with unidirectional core stiffeners are known for their relatively high bending stiffness at low weight, stability under compressive and shear loads and energy absorption capability. In this study, 3D printing was used to screen biocomposite sandwich panels easily and preliminarily with different unidirectional core stiffener designs. Thermomechanical pulp (TMP) fibre-reinforced poly(lactic acid) (PLA) was used in this study.A corrugated, trapezoid and arched cell structure were tested experimentally and numerically using a bimodular material model, accounting for different behaviour in tension and compression. The trapezoid structure showed the best flexural properties of the three 3D-printed sandwich beams. It was chosen to be explored further, manufacturing it by extrusion. Extrusion is a production process likely to be used in industry on a larger scale.Basic material properties of the biocomposites were obtained from injection moulded dogbone specimens. The flexural properties of the extruded panels were measured experimentally and simulated using finite element analysis. Simulations were done with a hyperelastic material model. Predictions and experiments were in adequate agreement, allowing such kind of simulation to be used for extruded biocomposite sandwich panels.

High tensile performance of PLA fiber-reinforced PCL composite via a synergistic process of strain and crystallization

Poly (lacticacid) (PLA) fiber-reinforced poly (ε-caprolactone) (PCL) composite is used in a broad variety of biocompatible and biodegradable materials, while phase separation remains an obstacle to mechanical performance. In this work, the PLA fiber-reinforced PCL composite membranes were prepared by multi-spinneret blended electrospinning, followed various synergistic processes of strain and melt-recrystallization. In the composite, the micro-scaled electrospun PLA fibers, which accomplished glass transition and partial crystallization during the annealing processing, profoundly reinforce the PCL matrix. The orientation and crystallinity of PLA fibers as well as the interfacial bond are improved by the manipulations of strain and supercooling during the crystallization of PCL domains in the composite. As a result, the tensile performance of the composite is greatly improved, which exhibits a modulus of 6.146 GPa and strength of 32.85 MPa, respectively, achieving a high level of strength among the PCL/PLA composites. This work offers a new approach to the preparation of PLA fiber-reinforced PCL composites with outstanding tensile performances.

A comparative life cycle assessment of graphene nanoplatelets- and glass fibre-reinforced poly(propylene) composites for automotive applications

The circulation of motor vehicles with an exhaust system is one of the leading causes of pollution. Due to the risk factor for human health and contribution to climate change, countries have been growing efforts to achieve a sustainable level of air quality and limit carbon dioxide (CO2) emissions in recent years. Hence, there has been significant interest in developing technological innovations such as alternative fuels and lighter thermoplastic composites for auto applications. Thermoplastic nanocomposites show substantial properties improvements, incorporating much lower nanofiller percentages than fibre-reinforced thermoplastic composites, allowing for a reduction in the weight of automotive parts (AP). For these motivations, this study presents a comparative life cycle assessment (LCA) of poly(propylene) (PP)–based graphene nanoplatelets (GnPs) nanocomposite and PP/glass fibre (GF) composite for automotive applications. The AP selected as the functional unit was the front end part of 1.5 tons weight car. The LCA included preparing raw materials, AP manufacturing, AP use, and AP end-of-life (EoL). Three different EoL scenarios were considered in this analysis. Several midpoint environmental impact indicators were evaluated. Overall, the results suggest that the different EoL scenarios do not affect the global environmental impact of both AP systems. The environmental impacts of the AP depend on the type of material. The AP of the PP-based GnPs nanocomposite exhibited a weight 28 % lower than the AP of the PP/GF composite. This lightweight resulted in energy and emissions savings, especially during the AP use stage, which was the stage with the most significant contribution in most environmental impact categories. Using nanocomposite reduced the AP environmental impact from 17 % to 75 %, depending on the impact category. The study suggested that substituting traditional composite with a new lighter nanocomposite can decrease the global environmental impacts caused by AP.

Hop natural fiber-reinforced poly(butylene succinate-co-butylene adipate) (PBSA) biodegradable plastics: effect of fiber length on the performance of biocomposites

Three sizes of hop fibers were tested at 30 wt% in PBSA biocomposites for material performance. Fibre length and size distribution were found to be key factors on mechanical and thermal properties of natural fiber-reinforced composites.

Scalable Manufacturing Process and Multifunctional Performance of Cotton Fibre-Reinforced Poly(Lactic Acid) (PLA) Bio-Composites Coated by Graphene Oxide.

Natural fibre biopolymer composites with both fibres and matrix being derived from biomaterials are increasingly used in demanding applications, such as sensing, packaging, building, and transport, and require good electrical, thermal, and flame retardant properties. Herein, an investigation of the effectiveness of functionalising nonwoven cotton/poly(lactic acid) (PLA) fibre mats with graphene oxide nanosheets has been reported by using a facile dip-coating method followed by thermal reduction for enhancing the electric, thermal, and abrasion-resistance properties. The manufacturing processes for preparing biocomposites and introducing functionality are readily scalable. Experimental results reveal that with the addition of less than 0.5 wt% graphene nanoplatelets, the biocomposites showed significant improvements in abrasion resistance, electrical conductivity, thermal conductivity, and diffusivity. Furthermore, the composite shows excellent piezo-resistivity to act as strain sensors with a gauge factor of 2.59 at strains up to 1%.

Analysis and development of a brazing method to weld carbon fiber-reinforced poly ether ketone ketone with amorphous PEKK

In this study, a brazing method for carbon fiber-reinforced poly ether ketone ketone (CF-PEKK) is developed that allows welding below the melting temperature of the single components. During the manufacturing of CF-PEKK laminates, a pseudo-amorphous PEKK film is consolidated to its surface which acts as interlayer polymer during subsequent joining (brazing). Five different brazing temperatures, determined from thermal analysis of the material, are characterized for their weld quality mechanically, analytically, and through ultrasonic testing. Microanalytically Scanning Electron Microscope (SEM) investigations focus on the morphology of the weld zone in order to evaluate the diffusion processes at the interfaces. Compared to Differential Scanning Calorimetry measurements, the SEM investigations offer a basic understanding of the welded process and its influence on the welding properties. A welding temperature of 60 °C below the processing temperature of CF-PEKK laminates (380 °C) is shown to yield a welding factor of 0.93. Furthermore, based on the SEM investigation, it is possible to derive more promising improvement measures for the brazing method.

Mechanical performance of Continuous/Short carbon Fiber-Reinforced Poly(phenylene sulfide) composites

A method for improving the fracture resistance and mechanical strength behavior of polymer composites by incorporating short carbon fibers into continuous fiber/poly(phenylene sulfide) laminate was explored in this manuscript. This method involves the incorporation of short carbon fibers into continuous carbon fiber thermoplastic laminates, by using the hot compression molding technique. Characterization of a continuous and discontinuous carbon fiber composite material with poly(phenylene sulfide) matrix (S-CCF/PPS laminate) was performed by using tensile, V-Notched Iosipescu, combined load compression and impulse excitation tests. According to the found results for this composite material, it was observed that the tensile strength and the elastic modulus values were 41% and 48% lower than a composite reinforced only by continuous fiber, respectively. The shear strength of the mixed material was found to be 32% lower than a continuous carbon fiber composite. These results were expected since it was used a combination of 50% of continuous and 50% of short carbon fiber, in volume. However, the compression strength of the mixed composite was found to be only 11.9% lower than a laminate reinforced with solely continuous carbon fiber, showing a synergic gain in this case. In addition, the impulse excitation results show that the material mechanical properties are within the expected range, but a high dispersion of the values was observed due probably to the random nature of the discontinuous fiber. Furthermore, it was observed that the failure modes for the composite evaluated in this work are similar to those found for composites processed only with continuous reinforcements and that the models used during the simulations presented similar results to what was found experimentally.

Investigating Features and Output Correlation Coefficient of Natural Fiber-Reinforced Poly(lactic acid) Biocomposites

Polylactic acid (PLA) material has the potential to be applied in various industrial fields, but this material has shortcomings in terms of mechanical properties, especially mechanical strength, due to brittleness nature of PLA. The manufacture of PLA composite material with the addition of natural fibers as a reinforcing phase is one of the methods to increase the impact strength and maintain the biodegradable properties of the material. However, in theory, there are many factors that affect the mechanical properties of composite materials, thus making the mechanical properties of composites more complex than monolithic materials. The mechanical properties of these composite materials can be predicted using deep learning by paying attention to the relationship between factors, and between factors and their mechanical properties. This relationship has an important role in creating a predictive model with good accuracy. Therefore, correlation analysis is an important thing to do. Correlation analysis was applied using Python programming language to determine the relationship between the impact strength of natural fiber-reinforced PLA biocomposites with its feature information: chemical composition, density, dimensions, surface chemical treatment of natural fibers, matrix-reinforcement volume fraction, and the type of processing used to manufacture the material.

Recovery of phenol and acetic acid from glass fibre reinforced thermoplastic resin using catalytic pyrolysis process on ZSM-5 zeolite catalyst and its kinetic behaviour

Glass fibre-reinforced thermoplastic (GFRP) is the composite material of choice for engineers to improve their design, save expenses, and achieve sustainability goals, what leads to generation of a big quantity of GFRP waste (during production or as an end-life-product) that needs to be disposed of safely. In order to valorise GFRP waste, this research aims to recover phenol and acetic acid as high-added value chemical and energy products from the millions of tons of GFRP waste produced annually during the catalytic pyrolysis process. The experiments were performed on glass fibre-reinforced poly(methyl methacrylate)-PMMA (GF/PM) as a common and commercial thermoplastic resin in five stages. In the first stage, the thermal decomposition of the milled feedstock over different percentages of ZSM-5 zeolite catalyst to feedstock in the ranges 0.5–5 wt.% (w/w) was performed using TGA. The generated volatile products from TGA were analysed using TG-FTIR and GC/MS in the second and third stages, respectively. The fourth stage was used to study the kinetic behaviour of catalytic pyrolysis of the feedstock with different catalysts and at different heating conditions using isoconversional models. In the last stage, the experimental thermal decomposition curves were simulated numerically. The results showed that ZSM/GF/PM can decompose significantly in the ranges 320–460 °C. Meanwhile, 2 wt.% of catalyst-to-GF/PM ratio was sufficient to recover more than 48% of phenol, 23% of acetic acid, 19% carbon dioxide compounds at 30 °C/min with high intensity of aromatic benzene. Also, this batch gave a higher kinetic complexity in terms of activation energy in the ranges 100–200 kJ/mol (linear models) and 230–440 kJ/mol (nonlinear models). These results confirm that involvement of 2 wt.% ZSM-5 zeolite catalyst in the pyrolysis of GF/PM has a big impact on the formulated volatile components and their potential upscaling.

Laser Ablation Mechanism and Performance of Carbon Fiber-Reinforced Poly Aryl Ether Ketone (PAEK) Composites

The ablation mechanism and performance of carbon fiber (CF)-reinforced poly aryl ether ketone (PAEK) thermoplastic composites were studied in this paper. The results show that the ablation damaged area is controlled by the irradiation energy, while the mass loss rate is controlled by the irradiation power density. In the ablation center, the PAEK resin and CFs underwent decomposition and sublimation in an anaerobic environment. In the transition zone, the resin experienced decomposition and remelting in an aerobic environment, and massive char leaves were present in the cross section. In the heat-affected zone, only remelting of the resin was observed. The fusion and decomposition of the resin caused delamination and pores in the composites. Moreover, oxygen appeared crucial to the ablation morphology of CFs. In an aerobic environment, a regular cross section formed, while in an anaerobic environment, a cortex–core structure formed. The cortex–core structure of CF inside the ablation pit was caused by the inhomogeneity of fibers along the radial direction and the residual carbon layer generated by resin decomposition in an anoxic environment. The description of the ablation mechanism presented in this study broadens our understanding of damage evolution in thermoplastic composites subjected to high-energy CW laser irradiation.

Modeling the effect of gauge length on the mechanical properties of Chitin Whiskers reinforced composites

Mechanical properties (tensile strength and modulus) of Chitin Whiskers fibre-reinforced poly(acrylic acid) with different fibre loading and different gauge lengths are compared with theories of reinforcement. The addition of random oriented Chitin Whiskers to poly(acrylic acid) matrix increased in tensile strength and elastic modulus of the composite. There was a steady increase in tensile stress and Elastic modulus within the volume fraction range investigated. The properties of the composite at different gauge lengths were studied. Within the same volume fraction, the tensile stress decreases as the gauge length increases. It is the reverse for the Elastic Modulus. Irrespective of filler loading and the theoretical modelling equations the tensile stress can be predicted at 40 mm gauge length. For the Elastic Modulus, the prediction of the property varies within the gauge lengths investigated. At higher filler loading, a smaller gauge length is required to predict the Elastic modulus. The comparative study between the tensile stresses obtained by experiment and selected theoretical models showed that the Parallel and Series models of the Rule of Mixture produced more accurate prediction, followed by Halpin-Tsai and modified Halpin-Tsai models. Guth's model was the least as the percentage deviation from the experimental data was very high when predicting the Elastic modulus. The density of the nanocomposite films were 1.08g/cm3, 1.023, and 1.024g/cm3 respectively, for 3%, 6%, and 9% weight filler and were in agreement with the theoretical data.