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Disposable surgical gowns are usually made from petroleum-based synthetic fibers that do not naturally decompose, impacting the environment. A promising approach to diminish the environmental impact of disposable gowns involves utilizing natural fibers and/or bio-based synthetic fibers. In this study, composite webs from polylactic acid (PLA) bicomponent fiber and natural fibers, cattail and kapok fibers, were prepared using the hot press method. Only the sheath region of the PLA bicomponent fiber melted, acting as an adhesive that enhanced the strength and reduced the thickness of the composite web compared with its state before hot pressing. The mechanical and physical properties of these composite webs were evaluated. Composite webs created from kapok fibers displayed a creamy yellowish-white color, while those made from cattail fibers showed a light yellowish-brown color. Additionally, the addition of natural fibers endowed the composite webs with hydrophobic properties. The maximum natural fiber content, at a ratio of 30:70 (natural fiber to PLA fiber), can be incorporated while maintaining proper water vapor permeability and mechanical properties. This nonwoven material presents an alternative with the potential to replace petroleum-based surgical gowns. [ABSTRACT FROM AUTHOR]

In this study, we utilized a hybridization approach for two different fibers to overcome the drawbacks of single-fiber-reinforced PLA composites. Coir fiber and bamboo leaf fiber were used as reinforcing natural fibers as their properties complement one another. Additionally, we combined thermal annealing with hybridization techniques to further improve the overall properties of the composites. The results showed that the hybridization of BF: CF with a ratio of 1:2 gave PLA-based hybrid composites optimal mechanical and thermal properties. Furthermore, the improvement in the thermal stability of hybrid composites, attributable to an increase in crystallinity, was a result of thermal annealing. The improvement in HDT in annealed 1BF:2CF hybrid composite was about 13.76% higher than that of the neat PLA. Annealing of the composites led to increased crystallinity, which was confirmed using differential scanning calorimetry (DSC). The synergistic effect of hybridization and annealing, leading to the improvement in the thermal properties, opened up the possibilities for the use of PLA-based composites. In this study, we demonstrated that a combined technique can be utilized as a strategy for improving the properties of 100% biocomposites and help overcome some limitations of the use of PLA in many applications. [ABSTRACT FROM AUTHOR]

A new class of biobased composites with tailorable mechanical properties made of natural fibers, polylactic acid, and ferulic acid derivatives (FAD) is studied. FAD was used to develop composites with elastomeric properties like improved elongation at break and highly reversible deformation upon elongation. Composites were prepared using raw and enzymatically treated hemp fibers. The fibers were defibrillated due to the enzymatic treatment increasing their aspect ratio. The composites were characterized by their mechanical properties and their reaction to fire. No significant change in the dispersion of the fibers in the composites was reported. Homogenously dispersed crystallites of FAD were observed by scanning electron microscopy in the PLA matrix and at the interface between the PLA and the fibers, where they are suspected to increase the free volume in correlation with a decrease in mechanical properties following the increase in the aspect ratio of the fibers. FAD also degraded the reaction to fire of the material with an increase in 10% of the peak of Heat Release Rate (pHRR) in comparison to neat PLA. It also increased the charring residue up to 3 wt.%. A synergistic effect between FAD and the lignin increasing the charring residue is also reported. [ABSTRACT FROM AUTHOR]

Thermomechanical pulp (TMP) fibres can serve as renewable, cost-efficient and lightweight reinforcement for thermoplastic polymers such as poly(lactic acid) (PLA). The reinforcing ability of TMP fibres can be reduced due to various factors, e.g., insufficient dispersion of the fibres in the matrix material, fibre shortening under processing and poor surface interaction between fibres and matrix. A two-level factorial design was created and PLA together with TMP fibres and an industrial and recyclable side stream were processed in a twin-screw microcompounder accordingly. From the obtained biocomposites, dogbone specimens were injection-moulded. These specimens were tensile tested, and the compounding parameters statistically evaluated. Additionally, the analysis included the melt flow index (MFI), a dynamic mechanical analysis (DMA), scanning electron microscopy (SEM) and three-dimensional X-ray micro tomography (X- μ CT). The assessment provided insight into the microstructure that could affect the mechanical performance of the biocomposites. The temperature turned out to be the major influence factor on tensile strength and elongation, while no significant difference was quantified for the tensile modulus. A temperature of 180 °C, screw speed of 50 rpm and compounding time of 1 min turned out to be the optimal settings. [ABSTRACT FROM AUTHOR]

To efficiently and economically utilize a wood-plastic biocomposite, an eco-friendly biocomposite was prepared using modified poplar fiber and polylactic acid (PLA) via 3D printing technology for the first time. First, the effects of poplar fiber (0, 1, 3, 5, 7, and 9%) on the mechanical and rheological properties of the printed biocomposites were investigated. Subsequently, the printing parameters, including printing temperature, speed, and layer thickness, were optimized to obtain the biocomposite with superior properties. Finally, four printing orientations were applied to the biocomposite based on the optimized printing parameters to study the effect of filament orientation on the properties of the biocomposite. Favorable printability and mechanical properties of the biocomposite were obtained at 5% poplar fiber. The optimal printing temperature of 220 °C, speed of 40 mm/s, and layer thickness of 0.2 mm were obtained to produce the desired mechanical properties of the biocomposite with the printing orientation in a longitudinal stripe. However, the printing parameters should be chosen according to the applications, where different physical and mechanical properties are needed to achieve efficient and economical utilization of the biocomposites. [ABSTRACT FROM AUTHOR]

In the material extrusion of the thermoplastic filaments, known as Fused Deposition Modelling, usually, pure thermoplastic polymers are used. Recently, the focus of the research is given to the development of new biocomposite thermoplastic materials. In our research, 3D printable biocomposite filaments, made with the addition of 50 wt.% of cardboard dust to the HDPE and PLA polymer matrix were studied. The influence of the added cardboard dust on structural, morphological and mechanical properties of the 3D printable biocomposite filaments was investigated. With the addition of the corrugated cardboard dust into the HDPE and PLA polymer matrix the changes in density, uniformity, chemical structure and transition temperatures of the samples were detected. The addition of the cardboard dust into the HDPE polymer matrix lead to low tenacity, toughness, deformability resulting in brittleness of the 3D printable biocomposite filament, whereas the addition of the cardboard dust into the PLA polymer matrix lowered tensile properties, but didn't affected bending toughness and has even improved compression strength of the 3D printable filament. [ABSTRACT FROM AUTHOR]

Biodegradable fiber-reinforced biocomposites from steam-exploded coconut fibers and polylactic acid (PLA) and polybutylene succinate (PBS) plastic were developed in this study. Biocomposite filaments and samples were produced using a commercial-scale screw extruder and a 3D printer, respectively. In-depth mechanical and thermal analyses were also performed. The results showed that the tensile strengths of PLA mixed with 3% coconut fiber (PLA97/F3) and 6% coconut fiber (PLA94/F6) decreased by approximately 22% and 23%, respectively, compared to the 64% reduction of that of the original PLA after four-week storage. The bending modulus of the PLA/fiber composite was better than that of the original PLA (21–29% higher), whereas a 5–8% improvement was observed for the PLA/PBS/fiber composites. The impact strengths of PLA97/F3 and PLA77/PBS20/F3 were approximately 8.5% and 7.4% higher than those of the original PLA and PLA/PBS, respectively. During the degradation test, both PLA97/F3 and PLA77/PBS20/F3 exhibited higher tensile strengths than the original materials. Finally, this research presents encouraging results for the production of biodegradable fiber-reinforced biocomposites that are applicable to 3D printing platforms. The final products can be used as replacement or aftermarket components of automobiles. • PLA, PBS, and steam-exploded coconut fiber were used for filament production. • The 3D-printed biocomposites were subjected to mechanical and thermal tests. • Coconut fiber is effective as a natural fiber reinforcement material. • The products have higher tensile strengths than original materials during degradation test. [ABSTRACT FROM AUTHOR]

Recycled polylactic acid (PLAr) was reinforced with treated nanocellulosic hemp fibers for biocomposite fabrication. Cellulosic fibers were extracted from hemp fibers chemically and treated enzymatically. Treated nanocellulosic fibers (NCF) were analyzed by Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Biocomposite fabrication was done with PLAr and three concentrations of treated NCF (0.1%, 0.25%, and 1% (v/v)) and then studied for thermal stability and mechanical properties. Increased thermal stability was observed with increasing NCF concentrations. The highest value for Young's modulus was for PLAr + 0.25% (v/v) NCF (250.28 ± 5.47 MPa), which was significantly increased compared to PLAr (p = 0.022). There was a significant decrease in the tensile stress at break point for PLAr + 0.25% (v/v) NCF and PLAr + 1% (v/v) NCF as compared to control (p = 0.006 and 0.002, respectively). No significant difference was observed between treatments for tensile stress at yield. [ABSTRACT FROM AUTHOR]