Polylactic Acid Biocomposites Research Articles

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.

Effects of combined alkali treatment and clay nanoparticle infusion on thermo-mechanical response of kenaf/PLA biocomposites

Fibre-reinforced biocomposites have inherently low thermo-mechanical properties and hence require some treatments or modifications during the fabrication process in order to enhance these properties. In this work, a combination of alkalization and nanoparticle infusion was used in enhancing thermo-mechanical properties of kenaf fibre-reinforced polylactic acid biocomposites. The biocomposites were made using sodium hydroxide (NaOH) treated kenaf nonwoven mats and polylactic acid infused with clay nanoparticles. Fabrication of the biocomposites was done using the prepreg method and curing at high temperature. Investigation of the thermo-mechanical properties were performed using a thermogravimetric analyser (TGA) and dynamic mechanical analyser (DMA). Results showed that a combination of alkalization and nanoparticle infusion improves the thermal stability of the biocomposites, loss modulus and damping. However, alkalization and nanoparticle infusion decreased the glass transition temperature of the biocomposites. The study shows that combined treatment of biocomposites with sodium hydroxide and clay nanoparticles significantly improves their performance properties. Therefore, this expands the application capabilities of natural fibre reinforced biocomposites. Best results were obtained by a combination of NaOH treatment and infusion with 5 wt% clay nanoparticles.

Effect of thermal annealing and filler ball-milling on the properties of highly filled polylactic acid/pecan nutshell biocomposites

Biodegradable polymer composites reinforced with agri-food lignocellulosic biowaste represent cost-effective and sustainable materials potentially able to replace traditional composites for structural, household, and packaging applications. Herein, the preparation of polylactic acid (PLA)/pecan (Carya illinoinensis) nutshell (PNS) biocomposites at high filler loading (50 wt%) is reported, alongside the effect of two environmentally friendly physical treatments, namely ball-milling of the filler and thermal annealing on biocomposites.PNS enhanced the thermal stability, the viscoelastic response, and the crystallinity of the polymer. Furthermore, filler ball-milling also increased the melt fluidity of the biocomposites, potentially improving melt processing. Finally, the presence of PNS remarkably enhanced the effect of thermal annealing in the compounds. In particular, heat deflection temperature of the biocomposites dramatically increased, up to 60 °C with respect to the non-annealed samples. Overall, these results emphasize the potential of combining natural fillers and environmentally benign physical treatments to tailor the properties of PLA biocomposites, especially for those applications which require a stiff and lightweight material with low deformability.

Surface treatment of lignocellulose biofiller for fabrication of sustainable polylactic acid biocomposite with high crystallinity and improved burning antidripping performance

In this work, we incorporated surface-treated coffee husks (CHs) into a polylactic acid matrix to fabricate environmentally friendly composites, with high crystallinity and satisfactory antidripping performance for flame retardancy. CHs are lignocelluloses that contain cellulose, hemicellulose, and lignin that are present as interlinked complex macromolecular structure. CH spectroscopic characterization confirmed that the phytic acid/amine silane agent was successfully attached and bonded with the cellulose portion of CHs. Morphological analysis of the composites revealed that the surface-treated CHs helped to improve the interfacial interaction between the filler and the matrix. Furthermore, the differential scanning calorimetry analysis showed that the crystallinity of the composites increased with CH loading. Flammability and combustion tests confirmed that the combined effect of P/Si/N on surface treatment improved the flame retardance behavior of the composites. The tensile strength and modulus of the composites exhibited a 28.7% and 34.4% increase compared with the corresponding composite with raw CHs.

Lignin Extraction and Characterization from Oil Palm Empty Fruit Bunches (Opefb) Using Soda and Dioxane Treatments for Polylactic Acid (Pla) Bio-Composites

Lignin Extraction and Characterization from Oil Palm Empty Fruit Bunches (Opefb) Using Soda and Dioxane Treatments for Polylactic Acid (Pla) Bio-Composites

A New Method for Producing Polylactic Acid Biocomposites for 3d Printing with Improved Tensile and Thermo-Mechanical Performance Using Grafted Nanofibrillated Cellulose

A New Method for Producing Polylactic Acid Biocomposites for 3d Printing with Improved Tensile and Thermo-Mechanical Performance Using Grafted Nanofibrillated Cellulose

Tensile properties of PolyLactic Acid Composite Foamed via Supercritical Carbon Dioxide

Tensile properties of foamed PolyLactic Acid (PLA) composite were studied. In this work, PLA were incorporate with Durian Skin Fibre (DSF) and Cinnamon Essential Oil (CEO) to form PLA bio composite and further treat via supercritical carbon dioxide (SCCO2) to form foamed PLA bio composite. The tensile strength value of foamed PLA bio composite slightly drops from foamed PLA. As for stress strain graph, the percentage of strain for foamed PLA and PLA bio composite did not distinct much. Through SEM, the foamed PLA bio composite showing that it did not fully foamed after treated via SCCO2 which due to treatment period and the thickness of the thin films.

Influence of agro-industrial wastes over the abiotic and composting degradation of polylactic acid biocomposites

Combining polylactic acid (PLA) with waste fibers to produce reinforced biocomposites is of top interest to replace conventional polymers for environmentally friendlier materials. Natural fibers have a remarkable effect on the mechanical and thermal properties of the biocomposites. This reinforcing effect strongly depends on the chemical compositions of fibers, which will also influence the susceptibility of the biocomposites to abiotic and biotic degradation processes. This study evaluated the effect of agave and coir waste fibers over the abiotic and composting degradation of PLA-based biocomposites. Compression-molded PLA/agave and PLA/coir biocomposites using GMA-g-PLA as compatibilizer were subjected to accelerated weathering. Weathered and unweathered samples were further submitted to water absorption to analyze their hydrolytic degradation and composting for biotic degradation. Both fibers showed significant influence on biocomposites degradation. The role of the fibers in UV and hydrolytic degradation was positive for impact properties since the biocomposites were less affected than PLA. Water uptake was increased with fiber addition, while hydrolytic degradation was decreased. The weathering (abiotic degradation) accelerated the PLA biodegradation rate. In general, the results showed that adding both fibers to PLA could help its outdoor performance, maintaining the biodegradable characteristics of these materials.

Properties enhancement of chitosan‐filled polylactic acid biocomposites using tannic acid treatment

AbstractIn this study, tannic acid‐treated chitosan (Cs‐TA)‐filled polylactic acid (PLA) biocomposites were fabricated through the melt blending and compression molding methods. The effects of Cs‐TA and their loadings (2.5, 5, 7.5, and 10) php on chemical interaction, tensile, melt processing, thermal, water absorption, and morphological characteristics were analyzed accordingly, and compared with a previously untreated PLA/Cs biocomposite. Fourier transform infrared spectroscopy analysis revealed that TA could form a cross‐linked network with Cs components as well as improving the hydrophilicity character of Cs for better interaction with PLA polymer. In addition, tensile strength and elongation at break were enhanced to the extent of ~3% and ~11%, respectively, at optimal 3% w/v TA concentration and 2.5 php Cs loading. Melt processing analysis of treated PLA/Cs‐TA demonstrated a lower stabilization torque, which implied improvement in the PLA processability. Moreover, chemical modification of Cs with TA showed a positive effect on thermal stability correlated to a higher decomposition temperature. Meanwhile, the crystallinity degree was considerably increased with TA treatment ascribed to the acceleration in crystallization process. Besides, a lower water uptake percentage proposed the Cs‐TA potential in controlling water uptake in PLA/Cs biocomposite. Indeed, the morphological analysis exhibited better filler dispersion and interfacial adhesion between Cs‐TA and PLA polymer, which justified the enhancement in all studied properties.

Valorization of Sugarcane Straw for the Development of Sustainable Biopolymer-Based Composites.

Sugarcane straw (SCS) is a common agro-industrial waste that is usually incinerated or discarded in fields after harvesting, increasing the importance of developing added-value applications for this residue. In this study, sustainable biocomposites were produced, and the effect of sugarcane straw as a filler/reinforcement of commercial biopolymers was evaluated. Biocomposites were prepared using polylactic acid (PLA), polyhydroxybutyrate (PHB), polyhydroxybutyrate-co-hydroxyvalerate (PHBV), or green polyethylene (Green-PE) with different fiber contents (20, 30, and 40 wt.%). Dry-blending followed by compression molding was used for the biocomposites preparation. The results showed that PLA, PHB, and PHBV biocomposites retained the same impact strength as the neat matrices, even with 40 wt.% of sugarcane straw. The flexural and tensile modulus of PLA, PHB, and PHBV biocomposites increased with 20% of SCS, whereas, in Green-PE biocomposites, these properties increased at all fiber contents. Since any compatibilizer was used, both the flexural and tensile strength decreased with the addition of SCS. However, even with the highest content of SCS, the tensile and flexural strength values were around 20 MPa, making these materials competitive for specific industrial applications.

A novel and multifunctional flame retardant nucleating agent towards superior fire safety and crystallization properties for biodegradable poly (lactic acid)

In engineering application area, it has always been a challenge to simultaneously improve flame-retardant performance and crystallization rate of polylactic acid (PLA) biomaterials, thus restricting their extensive application. In this work, a multifunctional additive (4,4′-(phenylphosphoryl)bis(piperazine-4,1-diyl))bis(diphenylphosphine oxide) (PDPO) was successfully synthesized and used to fabricate flame retardant PLA biocomposites. The crystallization behavior, fire safety, mechanical properties and flame retardant mechanisms of PLA biocomposites were studied in detail. The results indicated that PDPO notably improved the crystallization rate and crystallinity of PLA biocomposites. When 4 wt% PDPO was incorporated, PLA/PDPO biocomposites successfully passed UL-94V-0 grade and their LOI values were improved from 19.0% of pure PLA to 29.4%. The introduction of PDPO promoted the premature degradation and carbonization of PLA substrate, and inhibited the transesterification of the PLA during thermal pyrolysis process. Besides, PDPO decomposed and produced the Ph and PO, which efficiently exerted the free radical trapping effect in vapor phase. Therefore, the spread of fire for PLA/PDPO was declined and even self-extinguished. Meanwhile, the low addition of PDPO presented little effect on the mechanical properties of PLA composites. This flame retardant PLA biocomposites showed broad application prospects in emerging fields such as electronic devices, automobiles, and 3D printing materials.

Wear properties of waste silk fibre reinforced PLA bio composites using taguchi technique

In the last two decades, composites that are biodegradable and environmentally friendly are becoming more popular. In this paper, Biodegradable polylactic acid (PLA) biocomposites reinforced with waste silk fiber were fabricated using the hot molding technique. PLA bio-composites containing silk fibers had better wear properties, according to the findings. For superior properties, the fiber content of 30% by weight is ideal. A silk-based biodegradable composite with enhanced mechanical and wear properties can be designed due to this research. Taguchi’s L25 orthogonal array was used to study sliding speed (S), wear load (L), fiber loading (F), and abrasive distance (D). The ANOVA results found that the abrading distance was the most significant parameter, with load, sliding velocity, and fiber loading in order of importance.

Mechanical properties of waste silk fibre reinforced PLA bio composites manufactured through hand layup method

In recent years, biodegradable and eco-friendly composites have gained popularity. Using the hot moulding technique, biodegradable polylactic acid (PLA) biocomposites reinforced with waste silk fibre were fabricated in this paper. They also underwent a variety of mechanical tests like tensile strength and modulus. While not surface-treated, the waste silk fibre reinforced PLA matrix bio composites mechanical properties. The fibre content of 30 wt per cent is optimal for achieving superior properties. Owing to the reinforcing effect of silk fibres, the quasi-static mechanical properties of waste silk fibre/PLA bio composites were enhanced.

On the use of prickly pear seed fibres as reinforcement in polylactic acid biocomposites

On the use of prickly pear seed fibres as reinforcement in polylactic acid biocomposites

Processing of PLA/pineapple fiber based next generation composites

ABSTRACT Nowadays, the research fraternity across the globe is putting incredible efforts toward the development of sustainable materials. During this endeavor, the potential of sustainable biocomposites incorporating natural fibers as reinforcement and biopolymers as the matrix has received widespread attention for addressing the challenges associated with synthetic fibers and petroleum-derived polymers. However, the limited information about the processing guidelines for these materials and the lack of scientific evidence on how the processing routes affect the performance of the fabricated composites have limited their usage in several commercial applications. In the current investigation, three manufacturing routes, direct-injection molding (DIM) without compounding; compounding using extrusion followed by injection molding (EIM); and compounding using extrusion followed by compression molding (ECM) have been adopted to develop pineapple fibers (PFs)/poly-lactic acid (PLA) biocomposites. The investigation revealed that the crystallinity, visco-elastic, and mechanical responses of the composites fabricated by EIM significantly dominate the composites fabricated by DIM and ECM. The microstructural analysis confirms the severe attrition of fibers during ECM. The thermal analysis of the fabricated composites established that the important responses; glass transition, crystallization, and melting temperature, are independent of the choice of the manufacturing process.

Biodegradation properties and thermogravimetric analysis of 3D braided flax PLA textile composites

Recent advances in the development and application of bio-based (natural fiber and biopolymer) composites are gaining broad attention because the resulting polymer completely degrades and does not release harmful substances. In this study, natural fiber 3 D braided yarn textile PLA (Polylactic acid) bio-composites are developed by film sequencing followed by hot-press compression molding. Bio-deterioration and thermal stability of the composites are analysed for storage, machining, transportation, and in-service uses in different environmental conditions (compost and thermal). Composite samples with different fiber wt.% (0, 22, 44) are exposed to compost soil. Tensile testing is performed under different configurations to characterise the tensile properties. Prepared bio-composite specimens are evaluated for weight loss and reduction in tensile properties over soil burial time, to observe the rate of biodegradation of braided yarn textile bio-composites. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) is employed to analyse the biodegradability of the composites. To study the thermal stability of the prepared bio-composites thermogravimetric (TG) analysis is carried out. Results showed that biodegradability, tensile properties and thermal stability of the composites are enhanced significantly with the reinforcement of 3 D braided yarn fabric.

Polylactic Acid (PLA) Biocomposite: Processing, Additive Manufacturing and Advanced Applications.

Over recent years, enthusiasm towards the manufacturing of biopolymers has attracted considerable attention due to the rising concern about depleting resources and worsening pollution. Among the biopolymers available in the world, polylactic acid (PLA) is one of the highest biopolymers produced globally and thus, making it suitable for product commercialisation. Therefore, the effectiveness of natural fibre reinforced PLA composite as an alternative material to substitute the non-renewable petroleum-based materials has been examined by researchers. The type of fibre used in fibre/matrix adhesion is very important because it influences the biocomposites’ mechanical properties. Besides that, an outline of the present circumstance of natural fibre-reinforced PLA 3D printing, as well as its functions in 4D printing for applications of stimuli-responsive polymers were also discussed. This research paper aims to present the development and conducted studies on PLA-based natural fibre bio-composites over the last decade. This work reviews recent PLA-derived bio-composite research related to PLA synthesis and biodegradation, its properties, processes, challenges and prospects.

Fabrication and mechanical properties of braided flax fabric polylactic acid bio-composites

This paper primarily describes the development of flax braided yarn fabric reinforced thermoplastic composites. Plain woven fabric is made by interlacing 3D braided yarn produced by solid braiding method. Tensile properties of braided yarn and woven fabric are evaluated. Solution casting is used prior to composite fabrication to prepare polylactic acid (PLA) and (natural fiber braided fabric) NFBF–PLA sheets. Followed by this, composite laminates are prepared using through film stacking and compression molding. Influence of number of layers of fabric and loading along warp and weft directions on mechanical properties such as tensile, flexural and impact properties are presented. It is observed that the reinforcement enhances the tensile, flexural and impact properties of the composite significantly for the warp loading. Results also clearly indicates that braided yarn fabric reinforcement have the potential for significant improvement of mechanical and thermal properties of PLA composites.

Preparation of Long Sisal Fiber-Reinforced Polylactic Acid Biocomposites with Highly Improved Mechanical Performance.

Green biodegradable plastics have come into focus as an alternative to restricted plastic products. In this paper, continuous long sisal fiber (SF)/polylactic acid (PLA) premixes were prepared by an extrusion-rolling blending process, and then unidirectional continuous long sisal fiber-reinforced PLA composites (LSFCs) were prepared by compression molding to explore the effect of long fiber on the mechanical properties of sisal fiber-reinforced composites. As a comparison, random short sisal fiber-reinforced PLA composites (SSFCs) were prepared by open milling and molding. The experimental results show that continuous long sisal fiber/PLA premixes could be successfully obtained from this pre-blending process. It was found that the presence of long sisal fibers could greatly improve the tensile strength of LSFC material along the fiber extension direction and slightly increase its tensile elongation. Continuous long fibers in LSFCs could greatly participate in supporting the load applied to the composite material. However, when comparing the mechanical properties of the two composite materials, the poor compatibility between the fiber and the matrix made fiber’s reinforcement effect not well reflected in SSFCs. Similarly, the flexural performance and impact performance of LSFCs had been improved considerably versus SSFCs.

Sludge Fiber Waste and Kraft Lignin Powder as Fillers in Polylactic Acid Biocomposites: Physical, Mechanical, and Thermal Properties.

In this investigation, sludge fibre waste (SFW) and Kraft lignin powder (KLP) are introduced into polylactic acid (PLA) matrix biocomposites. These alternative materials allow for both the reuse of fibre waste from paper mill sludge and a reduction in the amount of high-cost biopolymer used in the same volume. Proportions from 10 to 40 wt.% of SFW with the addition of 2.5% and 5% of KLP are incorporated in PLA by extrusion and injection moulding. The thermogravimetric properties, water absorption, tensile and flexural properties, and morphology of the fabricated biocomposites were investigated. According to the results, KLP contributes to thermically stabilising the loss resulting from the incorporation of SFW. Flexural and tensile tests reveal a more pronounced decrease in strength with an SFW ratio above 10%. The modulus of elasticity increases significantly with an SFW ratio above 20%. The strength properties are stabilised with the addition of 5% KLP. The addition of KLP presents a tendency to reduce water absorption obtained by the incorporation of SFW into biocomposites. Scanning electron micrographs evidence that KLP improves the interfacial adhesion by reducing the voids between fibres and PLA.