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The exploration of efficient catalysts for the ring-opening polymerization of cyclic esters has significant implications for the synthesis of biocompatible and biodegradable polymers. In this work, the simple catalyst lithium bis(trimethylsilyl)amide (LiHMDS) with high activity was explored in detail for the synthesis of polylactide (PLA). Using LiHMDS as the catalyst, various cyclic esters were polymerized to obtain diverse sustainable polyesters, such as poly(lactide), poly(δ-valerolactone), and poly(caprolactone), with controlled molecular weights and narrow molecular weight distributions. PLA synthesis was accomplished in just a few minutes at room temperature, contributing to the sustainable advancement of this polymer. [ABSTRACT FROM AUTHOR]

In this study, the biodegradability of poly(lactic acid) (PLA), the most widely produced bioplastic, and poly(3-hydroxybutyrate) (PHB), known for its very biodegradability, was investigated in soil and soil amended with nitrogen sources, such as treatment sludge and vermicompost. Biodegradability was evaluated over 180 days by measuring the amount of carbon dioxide (CO2) and analyzing samples with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). PLA showed a low biodegradation (6%) in soil, but this increased to 40% in soil amended with treatment sludge and 45% in soil amended with vermicompost. PHB completely degraded within 90 days in soil; however, this process extended to 120 days in soil amended with vermicompost and 150 days in soil amended with treatment sludge. The organic and microbial content of the amendments enhanced PLA biodegradation, while PHB degradation slowed after 50 days as microorganisms prioritized other organic matter. SEM and FTIR analyses after 60 days showed more intense degradation of both bioplastics in soil amended with vermicompost. These findings highlight the potential of treatment sludge and vermicompost for improving bioplastic degradation, contributing to sustainable waste management and soil enhancement. [ABSTRACT FROM AUTHOR]

A series of poly(lactic acid) (PLA)/biochar (BC) bio-composites filled with low amounts (1–5 wt%) of BC were prepared and characterized. The synthesis involved the in situ ring-opening polymerization (ROP) of lactide in the presence of two different types of BC named SWP550 and SWP700, having been produced by pyrolysis of softwood pellets at two different temperatures, 550 and 700 °C, respectively. The bio-composites were characterized by complementary techniques. The successful synthesis of PLA and PLA/BC bio-composites was directly demonstrated by the formation of new bonds, most probably between PLA and BC. Indirect evidence for that was obtained by the systematic molar mass reduction in the presence of BC. BC was found by transmission electron microscopy (TEM) micrographs to be well dispersed at the nanosize level, indicating that in situ polymerization is a technique quite efficient for producing bio-composites with finely dispersed BC additive. The molecular dynamics mapping is performed here via dielectric spectroscopy, moreover, for the first time in these PLA/BC systems. The strong PLA/BC interactions (due to the grafting) led to a systematic deceleration of segmental mobility (elevation of the Tg) in the bio-composites despite the opposite effect expected by the decrease in molar mass with the BC content increasing. In addition, the same interactions and chain-length reduction are responsible for the slight suppression of the PLA's crystallizability. The effects are slightly stronger for SWP700 as compared to SWP550. The crystal structure is rather similar between the unfilled matrix and the bio-composites, whereas, based on the overall data, the semicrystalline morphology is expected to be tighter in the bio-composites. The thermal stability and decomposition kinetics were also thoroughly studied. All materials exhibit good resistance to thermal degradation. Additionally, the mechanical properties of bio-composites were evaluated by tensile testing and found slightly enhanced at low biochar contents and decreasing thereafter due to the low molecular weight of bio-composites with the larger BC contents. [ABSTRACT FROM AUTHOR]

In this study, an aluminate coupling agent (ACA) was utilized to modify calcium carbonate (CaCO₃) particles, producing modified CaCO₃ (Al-CaCO₃) particles, which were subsequently employed as inorganic fillers to enhance the toughness of polylactide (PLA). PLA/Al-CaCO₃ composites were prepared through melt mixing, with the reaction between ACA and CaCO₃ confirmed by Fourier transform infrared (FTIR) spectroscopy. The mechanical, thermal, and biodegradation properties of these composites were thoroughly investigated. The addition of Al-CaCO₃ significantly enhanced the mechanical properties, with impact strength reaching approximately 9.7 kJ/m2, a 143% increase compared to neat PLA. The elongation at break also improved dramatically, rising from 7.5 to 34%, representing a 350% increase over neat PLA. Al-CaCO₃ particles demonstrated good dispersibility and strong interfacial interaction within the PLA matrix. Differential scanning calorimetry (DSC) results showed that Al-CaCO₃ enhanced the crystallization behavior of PLA, promoting the formation of more perfect crystals. Additionally, biodegradation tests revealed that the PLA/Al-CaCO₃ composites exhibited excellent biodegradation properties. The combined toughening and biodegradation properties of PLA/Al-CaCO₃ broaden the potential applications of PLA. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) is a widely used biodegradable polymer, but its brittleness severely limits its further application. This study explores the preparation of anisotropic polylactic acid/thermoplastic polyurethane (PLA/TPU) foam through melt blending with elastomers, rolling, and supercritical fluid foaming (SCF), which substantially enhances the toughness of PLA. Results indicate that the crystallinity and elongation at break of PLA/TPU blend improve with increasing rolling temperature and rolling rate. Notably, at a rolling temperature and a rolling rate of 50%, the elongation at break for the PLA/TPU blends increases from 4.0 to 59.0%. In addition, SCF processing yields an anisotropic, highly oriented, and elongated cell structure within PLA/TPU foam. This cellular architecture further elevates the elongation at break of the rolled PLA/TPU blend to 76.8% and 1820.0%. This research offers a straightforward, environmentally friendly, and scalable method for fabricating high-strength PLA-based foam materials, equipping them with functionalities such as buffering, sound absorption, shock absorption, heat preservation, etc., which is suitable for electronics, home appliances, sports and other fields. [ABSTRACT FROM AUTHOR]

Extrusion-based 3D printing stands out as one of the most widespread additive manufacturing techniques, finding applications across engineering and medical sectors, primarily owing to its use of thermoplastic polymers. While poly(lactic acid) (PLA) remains among the most widely used bio-based compostable polymers in material extrusion, its inherent brittleness imposes limitations in sectors requiring more flexible and ductile materials. In this context, the combination of PLA with poly(butylene adipate-co-terephthalate) (PBAT) results in more flexible compostable blends, broadening the scope of advanced applications of 3D-printed parts while upholding sustainability standards. Despite the considerable potential of PLA/PBAT blends, research on their use in material extrusion 3D printing remains limited, highlighting an opportunity for significant advancements in the near future. Therefore, this article provides a detailed review of the influence of printing parameters on the properties of 3D-printed PLA/PBAT blends. It begins with a brief overview of the synthesis methods of PLA and PBAT, and their blend compatibilization strategies, showcasing advancements in the pursuit of versatile and sustainable materials. Furthermore, it also examines potential applications while identifying research gaps that can steer future investigations. In essence, this review not only provides valuable insights for optimizing the printing parameters of these blends in extrusion-based 3D printing but also contributes to the development of more adaptable and sustainable materials, holding substantial promise across various technological domains. [ABSTRACT FROM AUTHOR]

In this study, an aluminate coupling agent (ACA) was utilized to modify calcium carbonate (CaCO₃) particles, producing modified CaCO₃ (Al-CaCO₃) particles, which were subsequently employed as inorganic fillers to enhance the toughness of polylactide (PLA). PLA/Al-CaCO₃ composites were prepared through melt mixing, with the reaction between ACA and CaCO₃ confirmed by Fourier transform infrared (FTIR) spectroscopy. The mechanical, thermal, and biodegradation properties of these composites were thoroughly investigated. The addition of Al-CaCO₃ significantly enhanced the mechanical properties, with impact strength reaching approximately 9.7 kJ/m2, a 143% increase compared to neat PLA. The elongation at break also improved dramatically, rising from 7.5 to 34%, representing a 350% increase over neat PLA. Al-CaCO₃ particles demonstrated good dispersibility and strong interfacial interaction within the PLA matrix. Differential scanning calorimetry (DSC) results showed that Al-CaCO₃ enhanced the crystallization behavior of PLA, promoting the formation of more perfect crystals. Additionally, biodegradation tests revealed that the PLA/Al-CaCO₃ composites exhibited excellent biodegradation properties. The combined toughening and biodegradation properties of PLA/Al-CaCO₃ broaden the potential applications of PLA. [ABSTRACT FROM AUTHOR]

In this research, poly(lactic acid) (PLA) nanocomposites with multi-walled carbon nanotubes (MWCNT) were produced by extrusion, injection, and compression molding, focusing on electromagnetic shielding. Various amounts of carbon nanotubes (MWCNTs) were tested in PLA matrix, specifically ranging from 1 to 4 parts per hundred resin (phr). The resulting nanocomposites were analyzed before and after undergoing annealing heat treatment. It was observed that as the MWCNT content increased, the melt flow index of PLA decreased. This reduction indicates that the nanotubes were effectively accommodated into the PLA chain. The PLA/MWCNT (2 phr) formulation presented the greatest balance of properties, with potential for electromagnetic shielding application. Scanning electron microscopy (SEM) demonstrated that incorporating 2 phr of carbon nanotubes in PLA promoted good distribution, favoring high electrical conductivity and electromagnetic shielding between 20–22 dB (8.2–18 GHz), corresponding to approximately 99% attenuation. Furthermore, its properties, such as elastic modulus (3156 MPa), tensile strength (65.1 MPa), hardness (77.8 Shore D), and heat deflection temperature (55.3 °C), increased compared to pure PLA. After annealing, the PLA/MWCNT (2 phr) nanocomposite underwent a molecular reordering, resulting in an increased crystalline fraction, as confirmed by X-ray diffraction (XRD). However, the electrical conductivity maintained the same order of magnitude, while the electromagnetic shielding varied from 19.7 to 20 dB. The results indicate that these nanocomposites are promising for electromagnetic shielding applications and can be manufactured in the molten state. [ABSTRACT FROM AUTHOR]

Biomaterial-based implantable scaffolds capable of promoting physical and functional reconnection of injured spinal cord and nerves represent the latest frontier in neural tissue engineering. Here, we report the fabrication and characterization of self-standing, biocompatible and bioresorbable substrates endowed with both controlled nanotopography and electroactivity, intended for the design of transient implantable scaffolds for neural tissue engineering. In particular, we obtain conductive and nano-modulated poly(D,L-lactic acid) (PLA) and poly(lactic- co -glycolic acid) free-standing films by simply iterating a replica moulding process and coating the polymer with a thin layer of poly(3,4-ethylendioxythiophene) polystyrene sulfonate. The capability of the substrates to retain both surface patterning and electrical properties when exposed to a liquid environment has been evaluated by atomic force microscopy, electrochemical impedance spectroscopy and thermal characterizations. In particular, we show that PLA-based films maintain their surface nano-modulation for up to three weeks of exposure to a liquid environment, a time sufficient for promoting axonal anisotropic sprouting and growth during neuronal cell differentiation. In conclusion, the developed substrates represent a novel and easily-tunable platform to design bioresorbable implantable devices featuring both topographic and electrical cues. [ABSTRACT FROM AUTHOR]

This study investigates the incorporation of zinc oxide (ZnO) and ketoprofen (keto) into poly(lactic acid) (PLA) filaments to enhance their biocompatible. PLA is widely used in additive manufacturing, especially in biomedical applications, due to its biodegradability and biocompatibility. However, its interaction with biological tissues can be improved. ZnO was chosen for its wound-healing properties, while keto, a nonsteroidal anti-inflammatory drug, was selected to provide local anti-inflammatory effects. PLA filaments were prepared by incorporating ZnO and keto, followed by analyses of their mechanical, thermal, and biological properties. The results showed that the incorporation of ZnO and keto did not compromise the mechanical and thermal properties of the PLA filaments. Compared to pristine PLA, the composites presented a slight improvement in strength. The incorporation of ketoprofen in the composite increased its thermal stability compared to PLA-ZnO filament. Concerning the morphology, when ZnO and Keto were inserted, the scaffold acquired a more robust structure, with well-defined porosity. In vitro biocompatibility tests indicated that the modified filaments exhibited lower cellular toxicity and improved cell adhesion and proliferation compared to pure PLA. Antimicrobial tests demonstrated that the filaments containing ZnO, at the evaluated concentration, did not exhibit activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa, gram-positive and gram-negative bacteria. The combination of ZnO and ketoprofen in PLA filaments can enhance their biomedical applications, providing better biocompatibility without compromising the intrinsic characteristics of PLA. This work paves the way for the development of safer and more effective medical implants and devices. [ABSTRACT FROM AUTHOR]

The alarming rise in environmental pollution, depletion of global resources, and increasing health consciousness have placed significant pressure on the development of eco-friendly, sustainable materials. Consequently, green, environmentally friendly materials made from biobased and/or biodegradable sources are gaining recognition and political support as sustainable alternatives to petroleum-based, non-biodegradable materials. Bio-based packaging materials, in particular, are widely used across all industrial sectors, with a growing demand for solutions that preserve food quality and extend shelf life. Within this context, the concept of "active packaging" (AP) is attracting considerable interest. While the traditional view of packaging materials is that they should be basically inert, active packaging involves intentional interactions with the packaged product or surrounding atmosphere, providing enhanced protection against degradation caused by human actions and environmental factors. This work aims to highlight the significant impact of biocomposites in the active packaging sector, driven by the synergistic integration of nanofillers and active agents, while providing an in-depth analysis of the key mechanisms and strategies underlying their functionality. Particular emphasis is placed on poly(lactic acid)(PLA), presenting a comprehensive review of innovative approaches to enhance the performance of PLA-based packaging, with a focus on improving antioxidant and antimicrobial properties to meet the demands of sustainable and efficient packaging solutions. [ABSTRACT FROM AUTHOR]

Background: Amphotericin B (AmB) is a commonly utilized antifungal agent, which is also recommended for the treatment of certain neglected tropical diseases, including leishmaniasis. However, its clinical application is constrained because of its poor oral bioavailability and adverse effects, prompting the investigation of alternative drug delivery systems. Polymeric nanoparticles (PNPs) have gained attention as a potential drug delivery vehicle, providing advantages such as sustained release and enhanced bioavailability, and could have potential as AmB carriers. However, concerns persist regarding nanomaterials' toxicity, requiring more studies. Zebrafish (Danio rerio) embryos were used as a valuable model for toxicity testing, especially because of their genetic similarity to humans and standardized developmental assessments. Methods: In this study, we produced and characterized AmB loaded and non-loaded PNPs by nanoprecipitation, dynamic light scattering, transmission electron microscopy, atomic force microscopy and spectroscopy. Afterwards, we verified their toxicity through in vitro MTT assays in three cell lines (HEK293, HepG2, and J774 A1) and in vivo tests with zebrafish embryos. Results: In both trials, it was noted that nanoencapsulation of the drug led to increased toxicity when compared to non-encapsulated AmB, possibly indicating that they penetrated the embryo's chorion. Nevertheless, it was demonstrated that the polymers used are safe and they are not the cause of toxicity, neither are the nanostructures per se. Conclusions: Therefore, it is believed that the objective of improving the bioavailability of AmB may have been achieved, and the observed toxicity was probably linked to AmB's ability to destabilize cell membranes. [ABSTRACT FROM AUTHOR]

In the present work, the processability of poly(lactic acid) (PLA) in the extrusion foaming process was improved by using rice straw (RS) as an agricultural waste. In order to extrude a sustainable lightweight foam, the soda‐pulping and bleaching modification were performed on the RS particles, which resulted in the attainment of purified micron‐sized cellulosic fibre with higher aspect ratio. The addition of these fibres, with larger interfacial area between filler and matrix, to the PLA melt enhanced the foam void fraction and cell density more than one order of magnitude. The use of a reactive compatibilizer in the biocomposite showed further beneficial effects on the PLA foamability. The used reactive compatibilizer, with the ability of simultaneous reactions with the end groups of PLA macromolecules and hydroxyl groups of the lignocellulosic pulp, in the biocomposite noticeably improved the viscoelastic properties of melt and lengthened the macromolecule relaxation times. As a result, the biocomposite melt with higher melt strength was obtained, which kept the melt integrity during the bubble growth stage, hindered the cell coalescence, and retained a larger volume of gas inside the melt. Contrary to these influences, the compatibilization activity of this additive weakened the heterogeneous nucleation role of the cellulosic fibres. However, by choosing proper pulp loading, the extrusion of a lightweight biodegradable PLA‐based biocomposite foam can be feasible, which can be used in interior construction applications. [ABSTRACT FROM AUTHOR]

Fused Filament Fabrication (FFF) is the most used additive manufacturing (AM) technique. Understanding the behavior of the in situ temperature profile during the cooling stage is crucial to enhancing the mechanical properties of the parts manufactured by FFF since adhesion between printed layers is strongly related to the polymer cooling rate. However, only some studies analyze each layer in detail. For such analysis, infrared thermographic cameras can be used as a tool for non-contact temperature measurement. Numerous variables in constructing the part offer potential for such investigation. This study may lead to the enhancement of the part manufactured and improvements in the 3D printer itself. In addition, the polymer matrix and the manufacturing software can also be optimized. This work aims to systematically evaluate the temperature profile along the deposited layers during the fabrication of three-dimensional parts using poly(lactic acid) (PLA) filament. An infrared camera was used for real-time temperature measurements, and the data were processed with MATLAB® as a function of time and part length. A difference of up to 30 °C was observed between the edges, and non-uniform temperature profiles were also observed at the beginning, middle, and end of the part manufacturing. The highest temperatures were observed at the side where the print nozzle positions itself for the base to descend to the next layer. Several strategies are proposed to enhance the temperature distribution during the cooling process. [ABSTRACT FROM AUTHOR]

The present work focuses on the synthesis and characterization of biobased lignin-poly(lactic) acid (PLA) composites. Organosolv lignin, extracted from beechwood, was used as a filler at 0.5, 1.0, and 2.5 wt% loadings, with ultrasonication reducing the lignin particle size to ~700 nm. The PLA–lignin composites were prepared via in situ ring-opening polymerization (ROP) of L-lactide in the presence of lignin. This method ensured uniform lignin dispersion in the PLA matrix due to grafting of PLA chains onto lignin particles, preventing aggregation. Strong polymer–filler interactions were confirmed through spectroscopic analysis (FTIR and XPS) and their effects on static and dynamic glass transitions (DSC). These interactions enhanced mechanical properties, including a two-fold increase in tensile strength and elongation at 1 wt% lignin. Crystallization was suppressed due to shorter PLA chains, and a 15% drop in dynamical fragility was observed via Broadband Dielectric Spectroscopy (BDS). Antioxidant activity improved significantly, with PLA–2.5% ultrasonicated organosolv lignin reducing DPPH• content to 7% after 8 h, while UV-blocking capability increased with lignin content. [ABSTRACT FROM AUTHOR]

We studied the rheological properties under both shear and elongational flow and crystallization behaviors after shear history for binary blends of poly(lactic acid) (PLA) and ethylene–vinyl acetate copolymer (EVA) with a slightly lower shear viscosity. EVA was immiscible with PLA and dispersed in droplets in the blend. The addition of EVA significantly reduced the shear viscosity, which is attributed to the interfacial slippage between PLA and EVA. In contrast, under elongational flow, the addition of EVA provided strain hardening in the transient elongational viscosity. Consequently, the degree of neck-in behavior in T-die extrusion, i.e., a decrease in the film width, was reduced with the high orientation of the PLA chains. Furthermore, it was found that the addition of EVA accelerated the shear-induced crystallization of PLA, although EVA showed no nucleating ability without a flow field. Because the EVA addition can improve the mechanical toughness, this modification technique is attractive for various industrial applications of PLA. [ABSTRACT FROM AUTHOR]

Currently, toughening poly(lactic acid) (PLA) without reducing its strength and modulus is still challenging. Fortunately, this problem could be addressed by incorporating cellulose nanocrystals grafted with epoxidized soybean oil (CNCs‐g‐ESO) into the PLA matrix. The percolation threshold for uniform dispersion of the CNCs‐g‐ESO in the PLA matrix was about 0.8 wt%. The loading made the elongation at break and tensile fracture energy of the PLA composite film increase to 26.5 and 11.26 from 3.7% and 0.96 MJ.m−3, respectively, concerning the neat PLA. Meanwhile, it also resulted in a 4.7% and 12.4% increase in the tensile strength and Young's modulus, respectively. Additionally, the initial decomposition temperature (T5%) of the PLA composite increased to 334.9 from 316.1°C after incorporating the CNCs‐g‐ESO. Therefore, the CNCs‐g‐ESO, acting as an ESO‐like plasticizer and a CNCs‐like nucleating agent, is a potential nanofiller for reinforcing and toughening PLA. Highlights: Cellulose nanocrystal grafted with epoxidized soybean oil (CNCs‐g‐ESO)The CNCs‐g‐ESO acting as both plasticizer and nucleating agentThe CNCs‐g‐ESO decreasing the spherulite size, but increasing the CrI of PLAThe CNCs‐g‐ESO enlarging the window for thermal process of PLASimultaneous reinforcement and toughness of PLA [ABSTRACT FROM AUTHOR]

The introduction of biobased carbon sources in intumescent flame retardant formulations is extensively explored, particularly for biopolymers such as poly(lactic acid) (PLA). In this work, the flame retardant efficiency of alginate, a favorable renewable charring agent candidate, is enhanced by chemical modification with a phosphorus‐ and silicon‐containing compound and subsequent coagulation in the presence of Ca2+ ions. The simultaneous presence of P and Si atoms in the reactive compound is shown to be an effective way to avoid thermal stability issues related to the biobased carbohydrate. The newly synthesized PSilAlg additive boosts the flame‐retardant effectiveness of ammonium‐polyphosphate (APP) at low loadings. Adding 5 wt% PSilAlg to 15 wt% APP containing PLA composite increases the limiting oxygen index from 26.0 to 34.0 vol% and decreases the total heat emission during combustion by 46%, accompanied by significantly (by 66%) reduced smoke production. The outstanding flame retardant performance of PSilAlg is attributed to the high amount and thermally stable carbonaceous fire‐protecting layer that forms as a result of the enhanced charring, catalyzed by the high oxidation state P, and the strengthening mechanism of inorganic silicates and calcium salts. [ABSTRACT FROM AUTHOR]

The development and characterization of agricultural byproduct-based biocomposites are an important part of green chemistry. In this work, four-ingredient blends were formulated with the melt blending method. The set of composites (named as CSO series) was made with poly(lactic acid) (PLA) as the major matrix, washed cottonseed meal (WCSM) as a filler, cottonseed oil (CSO) as a compatibilizer, and glycerol (GLY) as a plasticizer. The morphological analysis showed the homogenous dispersion of the cottonseed byproducts into the PLA matrix to some extent. The thermogravimetric analysis revealed that thermal stability was impacted by the ingredient's addition. The functional group analysis of the sample and simulation by Fourier transform infrared spectra confirmed the chemical interactions of PLA with WCSM in the blend products. CSO was most likely subjected to physical blending into the products. The mechanical strengths of those composites were affected by the ratios of PLA-CSO. Generally, the tensile strengths were in the range of 0.74–2.1 MPa, which indicate its suitability for low-strength biodegradable plant container development. The blend products had a lower water absorption during the water soaking test. This work shows the feasibility of incorporating cottonseed WCSM and CSO into a PLA composite for sustainable agricultural applications. [ABSTRACT FROM AUTHOR]

At the present, the spent Pleurotus substrate (SPS), which is a lignocellulosic waste from the industrial production of mushrooms, is poorly valorized and mostly landfilled. Considering the large amount of SPS that is required to produce one kilo of mushrooms and its hazard to the environment if not properly disposed of, finding means to valorize this waste is of utmost importance. This work proposes the valorization of SPS through the extraction of cellulose nanofibers (NC-SPS), by applying several bleaching and alkaline hydrolysis treatments followed by microfluidization. Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA) of NC-SPS showed that most of the lignin, hemicelluloses, and other impurities were removed after the treatments of SPS. The transmission electron microscopy analysis of NC-SPS showed the presence of nanofibers with an average width of 24.5 ± 14.9 nm, XRD indicated an increase in crystallinity from 60% for SPS to 71% for NC-SPS, while TGA showed that the onset degradation temperature increased with about 43 °C after the treatments. The new NC-SPS are similar to the nanocellulose extracted from wood and can replace it in various applications. In this work, NC-SPS were tested as modifiers for poly(lactic acid) (PLA) leading to an increase in its crystallinity, Young's modulus (of up to 57%), and storage modulus, while preserving its thermal stability and transparency. These results showed that NC-SPS acted as good reinforcing agents for PLA, and more applications are foreseen. [ABSTRACT FROM AUTHOR]

Additive manufacturing is favored for its capacity to create intricate geometries and enhance component functionality more efficiently than traditional methods. Applying texture to materials is one of the processes used to add functionality to products, wherein it can improve adhesion and tribological behavior in biomedical applications while also controlling mechanical properties and providing perceptual and aesthetic improvements. In this study, custom black-white images containing vertical lines were prepared and added as textures to the design of tensile test specimens during slicing. Custom textured and untextured tensile test specimens were fabricated using the Fused Deposition Method with polylactic Acid filament to evaluate the effect of texture parameters, such as protrusion offset (0.25, 0.50, 0.75 mm), number of protrusions (3, 6) and infill pattern (rectilinear, line, concentric), on the tensile strength of the specimens. Through the analysis of tensile test results and examination of microscopic and slicing software images, it was found that texturing resulted in a reduction in ultimate tensile strength due to nozzle trajectory deviations and stress concentration. The least detrimental texturing parameters observed in this study were 0.5 mm protrusion offset and 3 protrusions with concentric and line infill patterns, resulting in a reduction in tensile strength of 2.36 and 5.79%, respectively when compared to untextured specimens.

The development and characterization of agricultural byproduct-based biocomposites are an important part of green chemistry. In this work, four-ingredient blends were formulated with the melt blending method. The set of composites (named as CSO series) was made with poly(lactic acid) (PLA) as the major matrix, washed cottonseed meal (WCSM) as a filler, cottonseed oil (CSO) as a compatibilizer, and glycerol (GLY) as a plasticizer. The morphological analysis showed the homogenous dispersion of the cottonseed byproducts into the PLA matrix to some extent. The thermogravimetric analysis revealed that thermal stability was impacted by the ingredient’s addition. The functional group analysis of the sample and simulation by Fourier transform infrared spectra confirmed the chemical interactions of PLA with WCSM in the blend products. CSO was most likely subjected to physical blending into the products. The mechanical strengths of those composites were affected by the ratios of PLA-CSO. Generally, the tensile strengths were in the range of 0.74–2.1 MPa, which indicate its suitability for low-strength biodegradable plant container development. The blend products had a lower water absorption during the water soaking test. This work shows the feasibility of incorporating cottonseed WCSM and CSO into a PLA composite for sustainable agricultural applications.

In order to prepare low-cost and heat-resistant poly(lactic acid) (PLA) composites, in this study, bamboo fiber (BF) was added to stereo-complex crystal PLA (SC-PLA) to prepare heat-resistant composites. Poly[(phenyl isocyanate)- co -formaldehyde] [a polyaryl polymethylene isocyanate (PAPI)] was used to form cross-linked structures between SC-PLA and BF, and the effects of PAPI-cross-linked structures on the crystallization properties, mechanical properties, and heat resistance of BF/SC-PLA composites with different BF contents were systematically investigated. When 15% BF was added, the mechanical properties of the composite were significantly improved. The tensile strength increased by 85.5% compared to the unmodified composite, reaching 34.7 MPa, which was even higher than that of the SC-PLA composite (33.1 MPa). In addition, in order to explore the impact of the PAPI-modified BF/SC-PLA composite on the environment and carbon emissions, a life cycle assessment (LCA) of the composites was conducted. The addition of BF effectively reduced the impact of the composite on the environment. Notably, the emissions of CO2 decreased by approximately 11.7%, and the freshwater, marine, and land ecotoxicity were also significantly reduced. This work provided a reference for the preparation of low-cost and heat-resistant PLA composites for heat-resistant food packaging and disposable tableware and expanded the application of PLA products in the field of heat-resistant materials. [ABSTRACT FROM AUTHOR]

The performance of incompatible blends is strongly depended on their morphology and interfacial properties that can be controlled by proper compatibilizers. This research systematically investigates the interfacial properties of the binary and the ternary blends based on low-density polyethylene (LDPE), poly(lactic acid) (PLA) and maleic anhydride-grafted polyethylene (PE-g-MAH) through the melt linear viscoelastic rheological behavior of the blends and neat components analyzed by proper rheological models. Moreover, the relationship between rheology, phase morphology and mechanical properties of LDPE/PLA ternary blends with different amounts of PE-g-MAH was studied. In the rheological analyses via the additive rule indicated in the molten state, no consistent interfacial interaction between LDPE and PLA phases is made due to the presence of PE-g-MAH at the interface of the blend. However, the analyses based on the Palierne's model implied that the interfacial tension of compatibilized blends decreases. This not only resulted in improving PLA dispersed phase morphology in the compatibilized blends, but also forming in situ fibrillar composites where the compatibilizer amount was relatively high (5 and 7.5 wt.%). Unlike the molten state, because of the strong interactions between PE and PLA phases of compatibilized blends in the solid state, the tensile mechanical properties, including Young's modulus, strength and elongation-at break, could be reinforced up to 24%, 25% and 90%, respectively. Overall, findings make a profound realization of the amount depended performance of PE-g-MAH as the most common compatibilizer for PE/PLA blends, very helpful not only from scientific viewpoints but also in terms of the blend industry applications. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAP) is a well-established material in biomedical applications, especially for bone tissue regeneration, dental implants, and drug delivery systems. Recent research emphasizes enhancing the biocompatibility and osteoconductivity of orthopedic implants using HAP. This study explores the potential of combining HAP with a lipid matrix to improve the surface properties and biocompatibility of poly(lactic acid) (PLA)-based, 3D-printed, resorbable bone implants. We utilized the Langmuir–Blodgett method to deposit HAP within a dihexadecyl phosphate (DHP) matrix onto PLA substrates. This study demonstrates that DHP and HAP form stable monolayers at the air/water interface with HAP particles distributed within a homogeneous lipid matrix. The presence of HAP and the resulting changes in surface free energy (SFE) are hypothesized to enhance the biocompatibility of PLA implants. Our findings indicate that films composed of DHP + HAP 5:1 are particularly effective in altering PLA surface characteristics, potentially improving osteointegration, and reducing microbial adherence. Overall, this work highlights that surface modification of PLA with HAP and lipid matrices is the first step towards new, promising, and cost-effective strategies for developing advanced biomaterials for bone regeneration. [ABSTRACT FROM AUTHOR]

This study investigates the crystallization, microstructure, and performance of poly(lactic acid)/poly(butylene succinate) (PLA/PBS) thin films processed through blown film extrusion and biaxial orientation (BO) at various blend ratios. Succinic anhydride (SA) was used to enhance interfacial adhesion in PLA-rich blends, while blends near 50/50 formed co-continuous phases without SA. Biaxial stretching and annealing, adjusted according to the crystallization behavior of PLA and PBS, significantly influenced crystallinity, crystallite size, and molecular orientation. Biaxial stretching induced crystallization and ordered chain alignment, particularly at the cold crystallization temperature (Tcc), leading to a 70–80-fold increase in impact resistance compared to blown films. Annealing further enhanced crystallinity, especially at the Tcc of PLA, resulting in larger crystallite sizes. BO films demonstrated reduced thermal shrinkage due to improved PLA crystalline structure, whereas PLA-rich blown films showed higher shrinkage due to PLA's lower thermal resistance. The SA-miscibilized phase reduced oxygen transmission in blown films, while BO films exhibited higher permeability due to anisotropic crystal orientation. However, the annealing of BO films, especially at high temperature (Tcc of PLA), further lowered oxygen permeability by promoting the crystallization of both PLA and PBS phases. Overall, the combination of SA compatibilization, biaxial stretching, and annealing resulted in substantial improvements in mechanical strength, dimensional stability, and oxygen barrier properties, highlighting the potential of these films for packaging applications. [ABSTRACT FROM AUTHOR]