Fiber Reinforced Poly Lactic Acid Research Articles

Investigation of the equivalent mechanical properties of the bone-inspired composite cellular structure: Analytical, numerical and experimental approaches

This study investigated the development of an analytical model using the energy method and Castigliano's second theory to evaluate the equivalent mechanical properties for a bone-inspired cellular structure of a glass fiber-reinforced Polylactic Acid (PLA) composite material. The bone-inspired cellular structure was fabricated using a Fused Deposition Modeling (FDM) 3D printing technique. The fabricated specimens were subjected to compression testing. The digital image correlation technique was employed for obtaining stain and displacement contours in experimental tests. Furthermore, a finite element numerical model was developed to evaluate the mechanical properties of the bone-inspired composite cellular structure. The comparison of the experimental and numerical results with the outcomes of analytical model revealed that the proposed analytical model can correctly determine the mechanical properties of the composite bio-inspired cellular structure. The results showed that by reinforcing the cellular structure with continuous fiber, significantly higher mechanical properties can be obtained. A comprehensive parametric study has also been performed to investigate the effect of geometric parameters on equivalent mechanical properties.

Residual stress and warpage of additively manufactured SCF/PLA composite parts

With the rapid development of novel technologies, additive manufacturing of carbon fiber-reinforced composites is drawing increasing attention in various industrial applications. In this study, we develop numerical models to predict and analyze the stress distribution, crystallinity and warpage mechanisms of two commonly used structural parts, i.e., a square tube (ST) and a circular tube (CT), made of short carbon fiber-reinforced polylactic acid (SCF/PLA) with additive manufacturing using fused filament fabrication (FFF). First, a multi-physics field model considering thermoelastic relations and crystallization kinetics was developed to simulate the FFF printing process using numerical “activated elements.” Then, the most important numerical parameters were experimentally evaluated to refine the numerical model for prediction and analysis. The results show that the composite ST specimens have a significant residual stress distribution and are prone to stress concentrations at the edges and corners. Specifically, the maximum warpage value, i.e., at the corner of ST specimens (100.47 µm), is higher than that of CT specimens (88.45 µm). Overall, the difference in crystallinity for additively manufactured composite tubes with different configurations is small (average crystallinities of ST and CT specimens are 5.22% and 6.1%, respectively). However, the crystallinity tends to generally decrease along the tube height direction, from the bottom upwards to the upper area beneath the printing nozzle.

Three-body abrasive wear behavior of rice straw fibers reinforced PLA composites

The current study focused on improving the abrasion resistance of rice straw fiber reinforced polylactic acid (PLA) composites. The effect of applied load and rice straw fiber loading on three-body abrasive wear behavior of PLA composites have been investigated. Rice straw fibers were treated with 2 wt% NaOH solution. Both the untreated and treated were produced by injection molding technique. Wear testing was performed on a dry sand/rubber wheel abrasion tester. According to the experimental results, fiber loading and applied load have a significant influence on composite wear loss. The results reveal that the abrasive wear loss of the composites decreases as fiber loading rises, whereas wear loss increases as applied normal load increases. SEM images were used to examine at the worn surfaces of the abraded samples to learn more about how the material was taken away. The treated fiber-reinforced PLA composites showed improvement in wear resistance than the untreated fiber reinforced PLA composites because the NaOH treatment of the fibers increased the fiber–matrix adhesion,

A Sustainable and Biodegradable Building Block: Review on Mechanical Properties of Bamboo Fibre Reinforced PLA Polymer Composites and Their Emerging Applications

The development of bamboo fibre (BF) reinforced poly lactic acid (PLA) BF-PLA composites has been growing fast among the natural fibre reinforced composites (NFRCs) over the past few years. BF-PLA composites have gained significant interest as sustainable alternative materials for the engineering and industrial sectors. BF-PLA composites are getting popular due to their remarkable features such as eco-friendliness, biodegradability, recyclability, low cost, low specific weight, and improved mechanical and thermal properties. In this paper, a schematic review of the BF-PLA composites was conducted in terms of mechanical properties (i.e., tensile properties, flexural properties, and impact strength), thermal characteristics with and without chemical treatment, and creep behaviour. Moreover, the sustainability aspects, including biodegradability and recyclability of BF-PLA composites, have been discussed based on various manufacturing methods. In addition, the utilization of BF-PLA composites in the additive manufacturing industry, sustainable packaging, structural, dielectric, and automotive applications are also described to make elevations toward future research and industrial implementations or commercialization. Furthermore, the effects of 3D printing parameters on the mechanical and physical properties of printed BF-PLA objects have been summarized. Significantly, this paper highlights the limitations and future perspectives of the BF-PLA composites.

Development and Mechanical Characterization of Short Curauá Fiber-Reinforced PLA Composites Made via Fused Deposition Modeling.

The increase in the use of additive manufacturing (AM) has led to the need for filaments with specific and functional properties in face of requirements of structural parts production. The use of eco-friendly reinforcements (i.e., natural fibers) as an alternative to those more traditional synthetic counterparts is still scarce and requires further investigation. The main objective of this work was to develop short curauá fiber-reinforced polylactic acid (PLA) composites made via fused deposition modeling. Three different fiber lengths (3, 6, and 8 mm), and three concentrations in terms of weight percentage (2, 3.5, and 5 wt.%) were used to fabricate reinforced PLA filaments. Tensile and flexural tests in accordance with their respective American Society for Testing and Materials (ASTM) standards were performed. A thermal analysis was also carried out in order to investigate the thermal stability of the new materials. It was found that the main driving factor for the variation in mechanical properties was the fiber weight fraction. The increase in fiber length did not provide any significant benefit on the mechanical properties of the curauá fiber-reinforced PLA composite printed parts. The composites produced with PLA filaments reinforced by 3 mm 2% curauá fiber presented the overall best mechanical and thermal properties of all studied groups. The curauá fiber-reinforced PLA composites made via fused deposition modeling may be a promising innovation to improve the performance of these materials, which might enable them to serve for new applications.

Enzymatic Degradation of Fiber-Reinforced PLA Composite Material

Application of thermoplastic fiber-reinforced lightweight composite materials provides a wide range of advantages that are of particular importance for the mobility sector. UD tapes composed of unidirectionally (UD) oriented inorganic fibers embedded in a thermoplastic matrix represent light-weight materials with high tensile strength. This publication addresses recycling aspects of novel UD tape made of a combination of basalt fibers and different PLA (polylactic acid) formulations. The kinetics of enzyme-based separation of polymer from the fiber were investigated. Different types of UD tapes with a thickness of 270–290 µm reinforced with basalt fiber weight ratios ranging between 51 and 63% were incubated at 37 °C in buffer solution (pH 7.4) containing proteinase K. The influence of enzyme concentration, tape weight per incubation tube, proteinase K activators, and tape types on the rate of enzymatic decomposition was investigated. Enzyme activity was measured by analyzing lactate concentration with lactate dehydrogenase and by measuring weight loss of the composite material. The rate of lactate release increased in the first 30 min of incubation and remained stable for at least 90 min. Weight loss of 4% within 4 h was achieved for a tape with 56% (w/w) fiber content. For a sample with a surface area of 3 cm2 in a buffer volume of 10 mL, the rate of lactate release as a function of enzyme concentration reached saturation at 300 µg enzyme/mL. With this enzyme concentration, the rate of lactate release increased in a linear manner for tape surface areas between 1 and 5 cm2. Four tapes with different PLA types were treated with the enzyme for 17 h. Weight loss ranged between 7 and 24%. Urea at a concentration of 0.5% (w/v) increased lactate release by a factor of 9. Pretreatment of tapes in alkaline medium before enzymatic degradation increased weight loss to 14% compared to 5% without pretreatment. It is concluded that enzymatic PLA hydrolysis from UD tapes is a promising technology for the release of basalt fibers after alkaline pretreatment or for the final cleaning of basalt fibers.

Influence of accelerated weathering on the properties of flax reinforced PLA biocomposites

The aim of the present study is to investigate the influence of accelerated weathering conditions (temperature and humidity) on the mechanical and physical properties of the flax fibre reinforced poly lactic acid (PLA) biocomposites. Two different types of biocomposites namely New Non-woven (NNW) and Conventional Non-woven (CNW) were developed for this study. After 500 h of exposure to humid environment with 95% relative humidity at 30 and 60 °C temperatures, the mechanical (tensile and flexural) and physical (surface roughness and hardness) behaviours were evaluated and compared with that of the dry specimens. Tensile and flexural properties were found to decrease significantly upon 500 h of exposure to accelerated weathering. The tensile strength of the biocomposite specimens exposed to 30 °C temperature and 95% RH demonstrated noteworthy improvement. Scanning electron microscopy (SEM) and X-ray micro CT images of fractured surfaces showed delamination, plasticization of matrix and fibre debonding due to exposure to various environmental conditions.

Mechanical characteristics and failure morphology of FFF-printed poly lactic acid composites reinforced with carbon fibre, graphene and MWCNTs

Fused Filament Fabrication (FFF) is the most prevalent additive manufacturing technique, which involves extruding a softened thermoplastic filament through the nozzle of a heated extruder. For improving the mechanical properties of the FFF-printed PLA parts one of the options is to add reinforcing material, such as carbonaceous materials or metal particles. The present study deals with analysing and comparing mechanical properties of carbon fibre reinforced poly lactic acid (CF-PLA), graphene reinforced PLA (Gr-PLA) and multi walled carbon nano tubes reinforced PLA (MWCNTs-PLA) composites by FFF. The selected process parameters used in this study are raster angle (0°, 45°, 90°), feed rate (20 mm/s, 40 mm/s, 60 mm/s) and layer height (0.1 mm, 0.15 mm, 0.2 mm) and based on different combinations, elongation at break, modulus and tensile strength are examined. MWCNTs-PLA exhibits overall maximum tensile strength, 37.438 MPa with 15.384% elongation at break for layer height 0.1 mm, raster angle 0° and feed rate 20 mm/s as compared to other selected specimens. Fractography analysis is also done to better understand the failure modes of specimens. To examine the dependency of the tensile strength on the process parameters, ANOVA, Taguchi’s L9 array Design of Experiment (DOE) is utilized indicating that layer height has the highest contribution of 56.713% for Gr-PLA, but raster angle has the highest contribution of 54.899% and 76.16% for CF-PLA and MWCNTs-PLA, respectively. This work will help in better understanding of how different parameters effects the material properties for PLA composites.

Effect of Nucleating Agents Addition on Thermal and Mechanical Properties of Natural Fiber-Reinforced Polylactic Acid Composites.

In this study, natural fiber-reinforced polylactic acid (NFRP) composite materials were prepared by adding nucleating agents (NAs) and natural fiber (NF) to compensate for the low thermal stability and brittleness of polylactic acid (PLA). The thermal stability of the fabricated composite material was investigated by differential scanning calorimetry and thermogravimetric analysis. In addition, the tensile modulus of elasticity according to the crystallinity of the composite was measured. The crystallinity of the PLA composite increased to ~700% upon the addition of the NA; thus, the thermal stability also increased. However, the changes in crystallinity and tensile modulus were insignificant when the concentration of the NA added was 4 wt.% or higher. The study demonstrates that the addition of NA and NF is effective in improving the thermal stability and mechanical properties of NFRP.

Strength Characteristics of Electrospun Coconut Fibre Reinforced Polylactic Acid: Experimental and Representative Volume Element (RVE) Prediction.

Environmental conservation and waste control have informed and encouraged the use of biodegradable polymeric materials over synthetic non-biodegradable materials. It has been recognized that nano-sized biodegradable materials possess relatively good properties as compared to conventional micron-sized materials. However, the strength characteristics of these materials are inferior to fossil-based non-biodegradable materials. In this study, biodegradable polylactide (PLA), reinforced with treated coconut husk particulates (CCP) for improved mechanical properties, was fabricated using an electrospinning process and representative volume element (RVE) technique, and some of the obtained mechanical properties were compared. It was observed that the electrospun CCP-PLA nanofibre composites show improved mechanical properties, and some of these mechanical properties using both techniques compared favourably well. The electrospun fibres demonstrate superior properties, mostly at 4 wt.% reinforcement. Thus, achieving good mechanical properties utilising agro waste as reinforcement in PLA to manufacture nanocomposite materials by electrospinning method is feasible and provides insight into the development of biodegradable nanocomposite materials.

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.

Mechanical Properties of 3D-Printed Orthopedic One-Third Tubular Plates and Cortical Screws

Aim: 3D printing is a growing technology with promising applications in orthopedic surgery. However, the utilization of 3D-printed surgical implants has not been fully explored. Materials & methods: One-third tubular plates and cortical screws were printed via fused deposition modeling using four materials: acrylonitrile butadiene styrene, carbon fiber-reinforced polylactic acid, polycarbonate and polyether ether ketone. Plates were analyzed with three-point bending and torque testing, and screws underwent torque, shear and pull-out testing. Results: Two-factor Analysis of Variance (ANOVA) demonstrated several significant differences between mechanical profiles for different materials and between designs. Conclusion: The results demonstrate that desktop 3D printers can print biocompatible materials to replicate surgical implant designs at a low cost. However, current materials and structures do not approximate the properties of stainless-steel implants.

Thermal and alkali modification of kaolin for potential utilization as filler material in fiber-reinforced polylactic acid composites

Thermal and alkali modification of kaolin for potential utilization as filler material in fiber-reinforced polylactic acid composites

Examination of water uptake performance and mechanical properties of PLA/flax fiber biocomposites with the coupling agent

The paper reports, the effect of water sorption on the microstructural and flexural properties of the flax fiber/ polylactic acid (PLA) biocomposites compared to the composites with maleic anhydride (MAH) as coupling agents and alkali treatment. In the current study, five different biocomposites which are 15 % wt. flax/PLA, 25 % wt. flax/PLA as control group and15 % wt. flax/PLA, 25 % wt. flax /PLA, and 35% wt. flax / PLA with 5 % wt. MAH was produced. Ten different soaking times were studied to understand the water absorption behavior of the biocomposites. To investigate mechanical properties of the biocomposites impact test was applied on the dry and 750 h, 1850 h water sorption composites. A three-point bending test was performed on the dry and 1850 h water sorption biocomposites to determine flexural properties. Short flax fiber-reinforced PLA matrix biocomposites were compounded using extrusion and manufactured by injection molding. Flax fiber surface was treated using sodium hydroxy solution to advance the interface interaction between fiber-matrix and surface performance of the fiber and matrix. According to the results, alkali treatment improved the water gain resistance of the composites since its enhancement of the interfacial bonding. Alkali-treated composites with maleic anhydride showed the better impact and flexural strength than composites without alkali-treated after 1850 h water sorption.

Micromechanics of Tensile Strength of Thermo-mechanical Pulp Reinforced Poly(lactic) Acid Biodegradable Composites

ABSTRACT Development of materials that are biobased and environmental sound is one of the goals within the current bioeconomy. This goal comes from an increasing conscientious society that pushes manufacturers and regulators toward a sustainable development. However, to be a feasible alternative, biobased materials should also match or outperform the mechanical performance of fossil-based materials. In this study, wood pulp fiber-reinforced polylactic acid (PLA) biocomposites were prepared, tested, and compared with glass fiber reinforced polypropylene. Pre-extrusion with a kinetic mixer and subsequent injection processing ensured correct dispersion of the reinforcement. The biocomposites showed mechanical properties in line with commercial materials, comparable to composites reinforced with 20% w/w of glass fiber. Micromechanics of PLA-based biocomposites showed the existence of strong interphase between the matrix and the pulp fibers. The interfacial shear strength was around 29 MPa and with a intrinsic tensile strength of the fibers 729 MPa. These materials offer a reliable alternative to oil-based matrices reinforced with mineral fibers.

Natural Fiber-Reinforced Polylactic Acid, Polylactic Acid Blends and Their Composites for Advanced Applications.

Polylactic acid (PLA) is a thermoplastic polymer produced from lactic acid that has been chiefly utilized in biodegradable material and as a composite matrix material. PLA is a prominent biomaterial that is widely used to replace traditional petrochemical-based polymers in various applications owing environmental concerns. Green composites have gained greater attention as ecological consciousness has grown since they have the potential to be more appealing than conventional petroleum-based composites, which are toxic and nonbiodegradable. PLA-based composites with natural fiber have been extensively utilized in a variety of applications, from packaging to medicine, due to their biodegradable, recyclable, high mechanical strength, low toxicity, good barrier properties, friendly processing, and excellent characteristics. A summary of natural fibers, green composites, and PLA, along with their respective properties, classification, functionality, and different processing methods, are discussed to discover the natural fiber-reinforced PLA composite material development for a wide range of applications. This work also emphasizes the research and properties of PLA-based green composites, PLA blend composites, and PLA hybrid composites over the past few years. PLA’s potential as a strong material in engineering applications areas is addressed. This review also covers issues, challenges, opportunities, and perspectives in developing and characterizing PLA-based green composites.

Wear and Morphological Analysis on Basalt/Sisal Hybrid Fiber Reinforced Poly lactic acid Composites

The investigation was undertaken to evaluate the wear behavior of basalt fiber and sisal fiber reinforced polylactic acid PLA composites. Basalt saline-treated chopped fiber and treated sisal chopped fiber were alloyed with polylactic acid and the samples were obtained using an injection mold in a twin-screw extruder. Three weight fraction samples were prepared, namely PBSi-1 (90% by weight polylactic acid, 5% by weight basalt and 5% by weight sisal), PBSi-2 (85% by weight polylactic acid, 7.5% by weight basalt and 7.5% by weight sisal) and PBSi-3 (80% by weight polylactic acid, 10% by weight basalt and 10% by weight sisal). The wear behavior of the prepared specimen were determined using a Pin-on-disc. The wear loss was measured at four different loads (10 N, 20 N, 30 N and 40 N) and four different sliding speeds (100 rpm, 150 rpm, 200 rpm and 250). The wear mechanism map was generated based on the wear regime nature using the Fuzzy Cluster C-means algorithm. The PBSi-3 composite showed a more mild wear regime than the severe and ultra-severe wear, due to the increase in the basalt and sisal fiber content within the composite that results in an increase of hardness and wear resistance. The predominant mechanism observed in the SEM image of PBSi-3 composite is ironing, which indicates the lesser wear occurrence in the composite.

Composite Multiaxial Mechanics: Laminate Design Optimization of Taper-Less Wind Turbine Blades with Ramie Fiber-Reinforced Polylactic Acid

As the research on composite materials based on natural resources proliferates further, ramie fiber and polylactic acid (PLA), which are fully biodegradable composite materials, are expected to be used for mechanical application due to their exce

Wood fiber-reinforced polylactic acid sheets enabled by papermaking

Polylactic acid is a biodegradable thermoplastic polyester derived from renewable polysaccharides. In this work, softwood fibers were used to reinforce the paper sheet made from polylactic acid fibers, thus addressing the challenges regarding low density, rough surface, and weak strength. The impact of wood fibers and calendering on the physical properties (density, roughness, tensile strength, and folding endurance) of the composite paper were identified. Furthermore, the morphology of papers with different fiber contents and those that had been calendered was characterized with a scanning electron microscope. The use of wood fibers resulted in the improvement of the physical properties of the polylactic acid paper, and the enhanced refining of wood fibers had a favorable role in improving paper density, smoothness, and mechanical strength. The tensile index increased 37.9% when the beating degree of wood fibers increased from 25 to 60 °SR. After calendering, the density, smoothness, tensile strength, folding endurance, and air barrier property of the paper were improved 60.2%, 45.8%, 15.5%, 148.1%, and 79.4%, respectively. The calendering-based papermaking process involving the combined use of wood fibers and polylactic acid fibers would be a promising strategy for designing composite materials for tailorable end-uses.

Optimization of tensile strength of PLA/clay/rice husk composites using Box-Behnken design

It is extremely important to save costs and time while enhancing accuracy in experimentation. However, no study has utilized response surface methodology (RSM) to obtain the effects of independent parameters on properties of PLA/clay/rice husk composites. This study focused on optimization of tensile strength of fiber-reinforced polylactic acid (PLA) composites. RSM using Box-Behnken design (BBD) was used to determine optimum blending parameters of the developed composites. Fiber-reinforced PLA composites were prepared using compression molding. Rice husk fiber and clay filler were used to enhance tensile properties of PLA. Five factors, namely, clay filler loading (1 − 5 wt.%), rice husk fiber loading (10 − 30 wt.%), alkali concentration (0 − 4 wt.%), rice husk variety (K85, K98), and alkali type (NaOH, Mg(OH)2) were varied with 68 individual experiments. Tensile tests were carried out according to ASTM D638 standards. ANOVA results revealed that the quadratic models best fit the tensile strength response, with filler loading and fiber loading factors as the most significant model terms. Interaction effects were more predominant than linear and quadratic effects. The developed models used to determine maximum tensile strengths of PLA/clay/rice husk composites were in close agreement with experimental findings (R2 values of 0.9635, 0.9624, 0.9789, and 0.9731 for NaOH-modified K85 rice husks, Mg(OH)2-modified K85 rice husks, NaOH-modified K98 rice husks, and Mg(OH)2-modified K98 rice husks respectively). Individual optimal conditions were used to predict maximum tensile strengths in each set of developed composites. The predicted tensile strengths were 32.09 MPa, 33.69 MPa, 32.47 MPa, and 32.75 MPa for PLA/clay composites loaded with NaOH-modified K85 rice husks, Mg(OH)2-modified K85 rice husks, NaOH-modified K98 rice husks, and Mg(OH)2-modified K98 rice husks, respectively, which were very close to the obtained experimental values of 31.73 MPa, 33.06 MPa, 32.02 MPa, and 31.86 MPa respectively.