Poly Lactic Acid Research Articles

Hepatopulmonary Shunt Ratio Verification Model for Transarterial Radioembolization.

The most important toxicity of transarterial radioembolization therapy applied in liver malignancies is radiation pneumonitis and fibrosis due to hepatopulmonary shunt of Yttrium-90 (90Y) microspheres. Currently, Technetium-99m macroaggregated albumin (99mTc-MAA) scintigraphic images are used to estimate lung shunt fraction (LSF) before treatment. The aim of this study was to create a phantom to calculate exact LFS rates according to 99mTc activities in the phantom and to compare these rates with LSF values calculated from scintigraphic images. A 3D-printed lung and liver phantom containing two liver tumors was developed from Polylactic Acid (PLA) material, which is similar to the normal-sized human body in terms of texture and density. Actual %LSFs were calculated by filling phantoms and tumors with 99mTc radionuclide. After the phantoms were placed in the water tank made of plexiglass material, planar, SPECT, and SPECT/CT images were obtained. The actual LSF ratio calculated from the activity amounts filled into the phantom was used for the verification of the quantification of scintigraphic images and the results obtained by the Simplicity90YTM method. In our experimental model, LSFs calculated from 99mTc activities filled into the lungs, normal liver, small tumor, and large tumor were found to be 0%, 6.2%, 10.8%, and 16.9%. According to these actual LSF values, LSF values were calculated from planar, SPECT/CT (without attenuation correction), and SPECT/CT (with both attenuation and scatter correction) scintigraphic images of the phantom. In each scintigraphy, doses were calculated for lung, small tumor, large tumor, normal liver, and Simplicity90YTM. The doses calculated from planar and SPECT/CT (NoAC+NoSC) images were found to be higher than the actual doses. The doses calculated from SPECT/CT (with AC+with SC) images and Simplicity90YTM were found to be closer to the real dose values. LSF is critical in dosimetry calculations of 90Y microsphere therapy. The newly introduced hepatopulmonary shunt phantom in this study is suitable for LSF verification for all models/brands of SPECT and SPECT/CT devices.

3D Printing and Biodegradable Polymers

Abstract 3D printing technology has a wide range of applications in many industries, including automotive, aerospace, biomedical, electronics and packaging, requiring different types of filaments to be used in producing 3D printed objects. The most commonly used materials are metals, ceramics, composites and plastics of which the latter are most available. Since it is necessary to reduce pollution caused by waste from conventional petroleum-based plastics, biodegradable polymers made from renewable resources or produced synthetically have gained in importance recently. Polylactic acid, poly(butylene succinate), thermoplastic starch, poly(butylene adipate co-terephthalate) and polycaprolactone are well-known representatives of this group of materials. They possess desirable properties for 3D printing which make them promising materials in many areas of applications.

A comparison of physical, morphological, and mechanical properties of bio‐polyester hybrid nanocomposites

AbstractIt is imperative to improve the physical, morphological, and mechanical properties of biodegradable polymers like polylactic acid (PLA), poly (butylene adipate‐co‐terephthalate) (PBAT), and polycaprolactone (PCL) in order to employ them on a larger scale. The development of hybrid nanocomposite materials using nano inclusions can improve desired qualities. Here we introduced an interactive nano reinforcement approach to improve the properties by combining graphene oxide (GO) and carboxyl functionalized MWCNT (f‐MWCNT), to provide for their chemical bonding for synergic reinforcement. A constant filler 2 wt.% was added to the biopolyesters by melt blending process and examined the different physical properties like water absorption, intrinsic viscosity, and hardness. To completely evaluate the functionalization of the nanofillers, wide‐angle X‐ray diffraction (WAXD), Raman spectroscopy and Fourier transform infrared radiation (FTIR) analyses were used. The paired nanoparticles and polymer matrix appear to mix well together, as shown by electron microscopy, which also reveals good dispersion and the creation of a reinforcing network microstructure across the matrix layer. A thorough analysis of the results showed that effective stress transmission, delaying the start of faults and generating microcracks, and dissipating additional mechanical energy all contributed to efficient hybrid network formation, which improved the mechanical properties of hybrid filler nanocomposites except some nanocomposites. These findings offer a viable technique for chemically altering biodegradable polymers, like PLA, PBAT, and PCL for use in biomedical, wastewater management, and agricultural applications.

Enhancing mechanical performance and water resistance of Careya-Banana fiber epoxy hybrid composites through PLA coating and alkali treatment

The ongoing research focuses on exploring the potential of Careya arborea (CA) fiber, banana fiber (BF), and epoxy composites as sustainable alternatives to petroleum-based products and synthetic fibers. The aim is to enhance the interfacial bonding and overall performance of these composites while reducing reliance on traditional materials. The study investigates the adhesion between CA fiber, BF (both chemically treated), and epoxy with polylactic acid (PLA) coating. Specifically, it examined how the PLA coating affects the mechanical properties, including tensile strength, flexural strength, impact resistance, and water absorption behavior, of the fabricated composites. Mechanical characterizations of the composite specimens are conducted following ASTM standards. The PLA-coated and NaOH-treated specimens significantly improved their tensile strength (20.56%) and flexural strength (16.7%), and significantly reduced their water absorption capacity (by 47.6%) compared to the untreated ones. These findings highlight the promise of using treated natural fibers and PLA coatings to create more sustainable and high-performance composite materials.

Evaluation of the Mechanical Properties of PLA Material Used For 3D Printing Solar E-Hub Component

The advent of additive manufacturing (AM) technologies revolutionized design and production processes across various industries. In renewable energy, AM enabled new possibilities for optimizing solar e-hub (solar energy harvesting module) configurations, enhancing efficiency and performance. This study examined critical considerations such as material selection, durability, and cost-effectiveness in solar hub development. This fast-prototyping technique was controlled by computer-aided design (CAD) software like CREO Parametric 7.0 and Creality Slicer 4.8. Experimental results indicated that PLA (Polylactic acid) materials exhibited superior strength, with an impact energy of 4.8 Joules. The deformation study revealed that the maximum load of 22 MPa aligned with the ultimate tensile strength of PLA, and a hardness test result of 83.1 HRF featured its exemplary hardness properties. These findings advanced the understanding of using AM to investigate mechanical behaviours of PLA materials and optimize solar e-hub configurations for portable device applications, promoting sustainable energy solutions and the adoption of renewable energy technologies. In addition, the successful implementation of this approach will enable the renewable energy sectors to minimize the carbon foot-prints towards helping the global net-zero emissions by aligning the circular economy approach.

Influence of pH value on erosive wear of 3D-printed polylactic acid for multiphase flow

Abstract Slurry erosion presents a critical challenge in hydrocarbon and cement processing industries, as well as in abrasive water jet cutting systems, leading to diminished operational efficiency and elevated maintenance costs. This study investigates the erosive wear behavior of Poly-Lactic Acid (PLA) fabricated with varying infill microtextures—zigzag, concentric, and grid—under diverse pH conditions (2.73, 7.75, and 10.15) using garnet particles as the erodent. The results demonstrate that optimal operational conditions for PLA are achieved with a grid microtexture, a pH of 7.75, and a 325 μm erodent size. Conversely, the most severe wear occurs under a pH of 10.15, a 600 μm erodent size, and a zigzag microtexture. The grid microtexture is the most effective in minimizing erosion, while the zigzag pattern shows a 16.68% increase in wear when compared to the grid microtexture. Additionally, a shift from a slightly basic to a highly acidic environment increases wear by 1%, whereas a transition to a highly basic environment leads to a 32.6% increase in erosion within the grid microtexture. The study highlights the significant contributions of infill microtexture (64%), erodent size (23.7%), and pH value (11%) to the overall erosion rate.

Polyester nanoparticles delivering chemotherapeutics: Learning from the past and looking to the future to enhance their clinical impact in tumor therapy.

Polymeric nanoparticles (NPs), specifically those comprised of biodegradable and biocompatible polyesters, have been heralded as a game-changing drug delivery platform. In fact, poly(α-hydroxy acids) such as polylactide (PLA), poly(lactide-co-glycolide) (PLGA), and poly(ε-caprolactone) (PCL) have been heavily researched in the past three decades as the material basis of polymeric NPs for drug delivery applications. As materials, these polymers have found success in resorbable sutures, biodegradable implants, and even monolithic, biodegradable platforms for sustained release of therapeutics (e.g., proteins and small molecules) and diagnostics. Few fields have gained more attention in drug delivery through polymeric NPs than cancer therapy. However, the clinical translational of polymeric nanomedicines for treating solid tumors has not been congruent with the fervor or funding in this particular field of research. Here, we attempt to provide a comprehensive snapshot of polyester NPs in the context of chemotherapeutic delivery. This includes a preliminary exploration of the polymeric nanomedicine in the cancer research space. We examine the various processes for producing polyester NPs, including methods for surface-functionalization, and related challenges. After a detailed overview of the multiple factors involved with the delivery of NPs to solid tumors, the crosstalk between particle design and interactions with biological systems is discussed. Finally, we report state-of-the-art approaches toward effective delivery of NPs to tumors, aiming at identifying new research areas and re-evaluating the reasons why some research avenues have underdelivered. We hope our effort will contribute to a better understanding of the gap to fill and delineate the future research work needed to bring polyester-based NPs closer to clinical application. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies.

EFFECT OF CHEMICAL MODIFICATION OF MULTIWALL CARBON NANOTUBES ON THE PROPERTIES OF POLY(LACTIC ACID) COMPOSITE FILMS: SYNTHESIS AND CHARACTERIZATION

To enhance the properties of poly(lactic acid) (PLA) composite films, unmodified (MWCNT) and modified multiwall carbon nanotubes (MWCNT-COOH, MWCNT-OH, and MA-g-MWCNT) were incorporated into the polymer matrix followed by the solvent casting method. The success of the modification of MWCNT with maleic anhydride (MA) was verified by absorption transmission reflectance spectroscopy (ATR). The fabricated nanocomposite films were analyzed by Fourier transform infrared (FT-IR) spectroscopy, thermal analyses, atomic force microscopy (AFM), contact angle measurements, dynamic mechanical analysis (DMA), and electrical conductivity tests. ATR spectra showed that MA was covalently grafted to the surface of the MWCNT, which was well dispersed and homogenously incorporated in the PLA matrix. The results of the thermal degradation demonstrated that the degradation value of the film increased from 328.91oC to 347oC with the addition of 0.5 wt% MA-g-MWCNT. Additionally, the MWCNT-OH/PLA films illustrated strongly hydrophilic nature due to the –OH groups. The surface resistance of 3 wt% of the MWCNT-COOH/PLA nanocomposite film decreased from 2.56x109 to 2.42x103 Ω (by 106 order). Therefore, the properties of PLA were increased with the addition of functionalized MWCNTs, which can be used for different applications such as biomedical, food packaging, and electronics.

Insights into the effect of carboxylated cellulose nanocrystals on mechanical and barrier properties of gelatin films for flexible packaging applications

In this study, gelatin/carboxylated cellulose nanocrystal (cCNC) bionanocomposite films were developed as an eco-friendly alternative to non-biodegradable flexible plastic packaging. Cellulose nanocrystals were modified by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation (cCNC) to strategically interact with amino groups present in the gelatin macromolecular backbone. Gelatin/cCNC bionanocomposite films (0.5–6.0 wt% cCNC) obtained by solution casting were transparent to visible light while displayed high UV-blocking properties. The chemical compatibility between gelatin and cCNC was deepened by electrostatic COO−/NH3+ interactions, as detected by FTIR spectroscopy and morphologically indicated by scanning electron microscopy (SEM). Accordingly, Young's modulus and tensile strength of films were largely increased by 80 and 64 %, respectively, specifically near the cCNC percolation threshold (4 wt%), whereas the water vapor permeability (WVP) was reduced by 52 % at the optimum 6.0 wt% cCNC content in relation to the non-reinforced gelatin matrix (0.10 vs. 0.18 g H2O mm m−2 h−1 kPa−1). The oxygen transmission rates (OTR) of the gelatin/cCNC bionanocomposites were < 0.01 cm3 m-2 day−1, making them technically competitive to most promising biopolymers like polycaprolactone (PCL) and poly(lactic acid) (PLA). This study reveals how TEMPO-oxidized cellulose nanocrystals can broaden the performance of biodegradable gelatin films for use in packaging. The gelatin/cCNC bionanocomposites also represents an effective approach for designing newly sustainability-inspired flexible materials from the surface modification of nanocelluloses targeting specific interactions with protein structures.

Cold Crystallization Behavior of Poly(Lactic Acid) Induced by Poly(Ethylene Glycol)-Grafted Graphene Oxide: Crystallization Kinetics and Polymorphism

Cold Crystallization Behavior of Poly(Lactic Acid) Induced by Poly(Ethylene Glycol)-Grafted Graphene Oxide: Crystallization Kinetics and Polymorphism

Simultaneously boosting the flame retardancy and degradability of poly(lactic acid) composite by phosvitin affiliation

Simultaneously boosting the flame retardancy and degradability of poly(lactic acid) composite by phosvitin affiliation

Full bio-based flame retardant towards multifunctional polylactic acid: Crystallization, flame retardant, antibacterial and enhanced mechanical properties

Full bio-based flame retardant towards multifunctional polylactic acid: Crystallization, flame retardant, antibacterial and enhanced mechanical properties

Experimental studies on mechanical properties of metal fused filament fabricated SS316L

Fused filament fabrication is a simple and commercially popular additive manufacturing (AM) technique for developing high-accuracy polymer-based materials. In this experiment, a retrofit type of setup was developed to manufacture stainless steel 316L–based products. The current study focuses on the encapsulation of stainless steel with polylactic acid to prepare the filament for 3D printing. The effects of printing parameters such as layer thickness, infill density, and extruder temperature on responses like density, surface roughness, micro-hardness, and material/filament consumption have been studied. A Box–Behnken design approach was employed to systematically evaluate 15 specimens under varying conditions. The results revealed that a maximum relative density of 97% was achieved with a layer thickness of 0.2 mm, an extruder temperature of 215°C, and a 100% infill density. Additionally, the optimized infill density demonstrated a significant effect on both hardness and surface roughness, confirming the importance of precise control over processing conditions for improving the performance of the printed parts. The findings contribute to the advancement of metal-polymer composite filaments in additive manufacturing, highlighting their potential for producing complex, high-performance components.

“Dual-purpose” strategy of achieving fire safety and UV-resistance of polylactic acid

“Dual-purpose” strategy of achieving fire safety and UV-resistance of polylactic acid

Continuous Oxidation of Organic Contaminates in Soil by Polylactic Acid-coated KMnO4

Potassium permanganate (KMnO4), as a versatile and safe solid source of MnO4-, received substantial attention from researchers as a potential soil oxidant reagent. In this study, we prepared polylactic acid (PLA)-coated KMnO4 (KMnO4@PLA) to control MnO4- release. The experimental results indicated that the optimal preparation scheme for KMnO4@PLA was a particle size of 1-2mm, a solid-liquid ratio of 1:3, and a core-shell ratio of 1:3. And the release lifetimes of MnO4- from KMnO4@PLA in aqueous and quartz sand media were 200hours and 310hours, respectively, which were 2,400 and 33 times longer than the release lifetimes of raw KMnO4. The controlled release of MnO4- from KMnO4@PLA was achieved through the hydrolysis of PLA. And the release process adhered to first-order reaction kinetics and displayed Fickian diffusion characteristics. Moreover, the removal of phenol by KMnO4@PLA in aqueous, quartz sand, and soil media were investigated through batch and flow column experiments. Compared with the raw KMnO4, the KMnO4@PLA exhibited a stronger ability to degrade phenol, due to the mildly acidic nature of the PLA shell. These findings demonstrated that KMnO4@PLA has significant advantages for the remediation of organically contaminated soils.

Effects of corrosion on mechanical properties of bolted porous structural panel

In this paper, polylactic acid materials combined with fused deposition molding technology were used to prepare porous structural panels. A combination of quasi-static compression experiment and finite element simulation analysis was adopted to explore effect of pitting time and concentration of dichloromethane solvent on the compression properties of porous structural panels. Results showed that surface of 100 % solvent became smooth and flat, while surface of 80 % solvent only formed a dense covering film. When specimens continues to suffer from corrosion, the single-layer specimens changed its deformation directions to a certain extent, while the instability of the two layers bolted porous structural panels gradually decreased when the corrosion damage increased. Mass concentration of 90 % was the critical point for local mechanical performance of specimens.

Bone regeneration in rabbit cranial defects: 3D printed polylactic acid scaffolds gradually enriched with marine bioderived calcium phosphate

Bone regeneration in rabbit cranial defects: 3D printed polylactic acid scaffolds gradually enriched with marine bioderived calcium phosphate

Enhancing functional properties of compostable materials with biobased plasticizers for potential food packaging applications

The demand of non-toxic and biobased plasticizers is substantially growing, particularly in biodegradable thermoplastics-based packaging applications. Herein, a derivative of citric acid (CITREM-LR10), usually used as food additive, was evaluated for the first time as plasticizer in PLA and Ecovio® biopolymers. Films containing 10 %(w/w) of CITREM-LR10 were prepared and compared with films plasticized with another biobased compound, SOFT-NSAFE, derived from acetic acid. The incorporation of both plasticizers provokes a slight reduction of the glass transition, however, only CITREM-LR10 was able to augment the elongation at break value of PLA films. A further evaluation of the films by Raman confocal microscopy showed the segregation of the CITREM-LR10 in microdomains, which could explain the enhanced elongation at break value, behaving as stress concentrators. In addition, CITREM-LR10 provides antimicrobial activity against S. aureus and both plasticizers give antioxidant properties, and almost negligible diffusion in food simulated solution. Composting studies showed that the plasticizers do not have effect on the disintegration rate of the films. In spite of these outstanding properties, the water vapour and oxygen barrier properties of the films worsen with its incorporation, therefore, the inclusion of fillers in the material together with the plasticizers would be necessary to improve such properties for food packaging applications.

The comparison effect on earthworms between conventional and biodegradable microplastics

Many studies have reported the toxic effects of microplastics (MPs) on organisms, especially on how conventional plastics affect organisms after short-term exposure. The effects of biodegradable plastics on organisms are, however, largely unexplored, especially concerning their impact after long-term exposure. We perform a series of experiments to examine the effects of conventional (polyethylene (PE)) and biodegradable (polylactic acid (PLA)) microplastics on earthworms at three concentrations (0.5 %, 2 %, and 5 % (w/w)) and particle sizes (149, 28, and 13 μm) over short- (14 d) and long-term (28 d) periods of exposure. Negative effects on earthworms are more pronounced following exposure to PE than PLA, particularly over the shorter term. After longer-term exposure, earthworms may adapt to PE and PLA environments. A close relationship exists between the effects of MPs on earthworms and activities of superoxide dismutase, catalase, and malondialdehyde enzymes, which we use to evaluate the degree of antioxidant damage. We report both PE and PLA to negatively affect earthworms, but for the effects of PLA to be less severe after longer-term exposure. Further investigation is required to more fully assess the potential negative effects of PLA use on soil organisms in agriculture.

Influence of additive manufacturing parameters by FFF on PLA tensile strength

When na object manufactured by 3D printing goes from prototype to a functional component, it is crucial to understand the mechanical properties of the material used. This knowledge determines the resistance limits of the object. Therefore, the objective of this research was to comparatively analyze the results obtained in tensile tests of specimens constructed with polylactic acid (PLA), printed in 3D, keeping the density constant and varying two construction parameters: the layer thickness and the geometry of the internal filling. The test specimens were made on a BFB Touch – Dual head-smoke 3D printer, in accordance with ASTM D638-14. Tensile tests were carried out using an EMIC model DL10000 testing machine, and the results were statistically analyzed for comparison. The results indicated that the maximum stress and fracture resistance increased with increasing thickness of the filament deposited by the extruder nozzle. Although PLA is often described in the literature as a brittle polymer, it has exhibited ductility characteristics when 3D printed, due to the alignment of fibers during the manufacturing process.