Investigation of the Biocidal Performance of Multi-Functional Resin/Copper Nanocomposites with Superior Mechanical Response in SLA 3D Printing

Metals, such as silver, gold, and copper are known for their biocidal properties, mimicking the host defense peptides (HDPs) of the immune system. Developing materials with such properties has great importance in medicine, especially when combined with 3D printing technology, which is an additional asset for various applications. In this work, copper nanoparticles were used as filler in stereolithography (SLA) ultraviolet (UV) cured commercial resin to induce such biocidal properties in the material. The nanocomposites developed featured enhanced mechanical responses when compared with the neat material. The prepared nanocomposites were employed to manufacture specimens with the SLA process, to be tested for their mechanical response according to international standards. The process followed was evaluated with Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetric analysis (TGA). The antibacterial activity of the fabricated nanocomposites was evaluated using the agar-well diffusion method. Results showed enhanced mechanical performance of approximately 33.7% in the tensile tests for the nanocomposites filled with 1.0 wt.%. ratios, when compared to the neat matrix material, while this loading showed sufficient antibacterial performance when compared to lower filler loadings, providing an added value for the fabrication of effective nanocomposites in medical applications with the SLA process.

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Affordable Biocidal Ultraviolet Cured Cuprous Oxide Filled Vat Photopolymerization Resin Nanocomposites with Enhanced Mechanical Properties

Biomimetics ◽

10.3390/biomimetics7010012 ◽

2022 ◽

Vol 7 (1) ◽

pp. 12

Author(s):

Markos Petousis ◽

Nectarios Vidakis ◽

Emmanuel Velidakis ◽

John D. Kechagias ◽

Constantine N. David ◽

...

Keyword(s):

3D Printing ◽

Cuprous Oxide ◽

Mechanical Performance ◽

Functional Performance ◽

Low Cost ◽

Three Dimensional ◽

Diffusion Method ◽

Host Defense Peptides ◽

Commercial Resin ◽

Antibacterial Performance

In this study, Cuprous Oxide (Cu2O), known for its mechanism against bacteria, was used as filler to induce biocidal properties on a common commercial resin stereolithography (SLA) 3D printing resin. The aim was to develop nanocomposites suitable for the SLA process with a low-cost process that mimic host defense peptides (HDPs). Such materials have a huge economic and societal influence on the global technological war on illness and exploiting 3D printing characteristics is an additional asset for these materials. Their mechanical performance was also investigated with tensile, flexural, Charpy’s impact, and Vickers microhardness tests. Morphological analysis was performed through scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray spectroscopy (EDS) analysis, while the thermal behavior was studied through Thermogravimetric Analysis (TGA). The antibacterial activity of the fabricated nanocomposites was investigated using a screening agar well diffusion method, for a gram-negative and a gram-positive bacterium. Three-dimensional printed nanocomposites exhibited antibacterial performance in all loadings studied, while their mechanical enhancement was approximately 20% even at low filler loadings, revealing a multi-functional performance and a potential of Cuprous Oxide implementation in SLA resin matrices for engineering and medical applications.

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Mechanical Performance of Long-fibre Reinforced Polymer Composites by 3D Printing

10.21203/rs.3.rs-31919/v1 ◽

2020 ◽

Author(s):

Francis Dantas ◽

Greg Gibbons

Keyword(s):

3D Printing ◽

Polymer Composites ◽

Mechanical Response ◽

Mechanical Performance ◽

Fibre Composite ◽

Flexural Modulus ◽

Matrix Material ◽

Base Material ◽

Fibre Reinforcement ◽

Number Of Layers

Abstract Additive Manufacturing (AM), also known as 3D Printing, has been around for more than 2 decades and has recently gained importance for use in direct manufacturing. The quantified physical properties of materials are required by design engineers to inform and validate their designs, and this is no less true for AM that it is for traditional manufacturing methods. Recent innovation in AM has seen the emergence of long-fibre composite AM technologies, such as the Mark Two (Markforged Inc, USA) system, enabling the manufacture of thermoplastic polymer composites with long-fibre reinforcement. To date though, the mechanical response of the materials with respect to build parameter variation is little understood. In this project, selected mechanical properties (ultimate tensile strength – UTS and flexural modulus) of samples processed using the Mark Two printer were studied. The effect of the reinforcement type (Carbon, Kevlar®, and HSHT glass), amount of reinforcement, reinforcement lay-up orientation, and the base matrix material (Onyx and polyamide) on these properties were assessed using accepted standard test methods. For Onyx, the UTS and Flexural Modulus was improved by a maximum of 244 ± 10 MPa (1228 ± 19%) and 14.2 ± 0.3 GPa (1114 ± 6%) (Carbon), by 143 ± 1 MPa (721 ± 18%) and 7.1 ± 0.3 GPa (560 ± 6%) (Kevlar®) and 209 ± 4 MPa (1049 ± 19%) and 6.0 ± 0.1 GPa (469 ± 6%) (HSHT glass). For Nylon the UTS and Flexural Modulus was improved by 235 ± 4 MPa (1431 ± 56%) and 14.1 ± 0.2 GPa (1924 ± 5%) (Carbon), 143 ± 3 MPa (867 ± 56%) and 6.79 ± 0.08 GPa (927 ± 5%) (Kevlar®) and 204 ± 2 MPa (1250 ± 55%) and 5.73 ± 0.09 GPa (782 ± 5%) (HSHT glass). A regression and ANOVA analysis for UTS indicated that the number of layers of reinforcement had the largest impact on UTS (F = 11,483 P < 0.005), with the second most important parameter being the type of reinforcement (F = 855 P < 0.005). The parameter effects for all four parameters were significant (P ≤ 0.05). For the Flexural Modulus, the number of layers of reinforcement was again the most significant parameter (F = 2733 P < 0.005), with the second most important parameter again being the type of reinforcement (F = 1339 P < 0.005). Again, the parameter effects for all four parameters were significant (P ≤ 0.05), although the influence of base material had much less significant effect on determining the Flexural Modulus than it did in controlling UTS.

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On the Mechanical Response of Silicon Dioxide Nanofiller Concentration on Fused Filament Fabrication 3D Printed Isotactic Polypropylene Nanocomposites

Polymers ◽

10.3390/polym13122029 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2029

Author(s):

Nectarios Vidakis ◽

Markos Petousis ◽

Emmanouil Velidakis ◽

Lazaros Tzounis ◽

Nikolaos Mountakis ◽

...

Keyword(s):

3D Printing ◽

Silicon Dioxide ◽

Mechanical Response ◽

Mechanical Performance ◽

Microstructural Analysis ◽

Melt Flow Index ◽

International Standards ◽

Flow Index ◽

Fused Filament Fabrication ◽

Melt Mixing

Utilization of advanced engineering thermoplastic materials in fused filament fabrication (FFF) 3D printing process is critical in expanding additive manufacturing (AM) applications. Polypropylene (PP) is a widely used thermoplastic material, while silicon dioxide (SiO2) nanoparticles (NPs), which can be found in many living organisms, are commonly employed as fillers in polymers to improve their mechanical properties and processability. In this work, PP/SiO2 nanocomposite filaments at various concentrations were developed following a melt mixing extrusion process, and used for FFF 3D printing of specimens’ characterization according to international standards. Tensile, flexural, impact, microhardness, and dynamic mechanical analysis (DMA) tests were conducted to determine the effect of the nanofiller loading on the mechanical and viscoelastic properties of the polymer matrix. Scanning electron microscopy (SEM), Raman spectroscopy and atomic force microscopy (AFM) were performed for microstructural analysis, and finally melt flow index (MFI) tests were conducted to assess the melt rheological properties. An improvement in the mechanical performance was observed for silica loading up to 2.0 wt.%, while 4.0 wt.% was a potential threshold revealing processability challenges. Overall, PP/SiO2 nanocomposites could be ideal candidates for advanced 3D printing engineering applications towards structural plastic components with enhanced mechanical performance.

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Mechanical Performance of Fused Filament Fabricated and 3D-Printed Polycarbonate Polymer and Polycarbonate/Cellulose Nanofiber Nanocomposites

Fibers ◽

10.3390/fib9110074 ◽

2021 ◽

Vol 9 (11) ◽

pp. 74

Author(s):

Nectarios Vidakis ◽

Markos Petousis ◽

Emmanouil Velidakis ◽

Mariza Spiridaki ◽

John D. Kechagias

Keyword(s):

3D Printing ◽

Mechanical Performance ◽

Matrix Material ◽

Mechanical Analysis ◽

Cellulose Nanofiber ◽

Fused Filament Fabrication ◽

Melt Mixing ◽

The Matrix ◽

3D Printed ◽

Printing Parameters

In this study, nanocomposites were fabricated with polycarbonate (PC) as the matrix material. Cellulose Nanofiber (CNF) at low filler loadings (0.5 wt.% and 1.0 wt.%) was used as the filler. Samples were produced using melt mixing extrusion with the Fused Filament Fabrication (FFF) process. The optimum 3D-printing parameters were experimentally determined and the required specimens for each tested material were manufactured using FFF 3D printing. Tests conducted for mechanical performance were tensile, flexural, impact, and Dynamic Mechanical Analysis (DMA) tests, while images of the side and the fracture area of the specimens were acquired using Scanning Electron Microscopy (SEM), aiming to determine the morphology of the specimens and the fracture mechanism. It was concluded that the filler’s ratio addition of 0.5 wt.% created the optimum performance when compared to pure PC and PC CNF 1.0 wt.% nanocomposite material.

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New Insights into the Application of 3D-Printing Technology in Hernia Repair

Materials ◽

10.3390/ma14227092 ◽

2021 ◽

Vol 14 (22) ◽

pp. 7092

Author(s):

Bárbara Pérez-Köhler ◽

Selma Benito-Martínez ◽

Verónica Gómez-Gil ◽

Marta Rodríguez ◽

Gemma Pascual ◽

...

Keyword(s):

3D Printing ◽

Hernia Repair ◽

Soft Tissues ◽

Mechanical Performance ◽

Abdominal Hernia ◽

Abdominal Muscles ◽

Contrast Imaging ◽

Printing Technology ◽

3D Printing Technology ◽

Antibacterial Performance

Abdominal hernia repair using prosthetic materials is among the surgical interventions most widely performed worldwide. These materials, or meshes, are implanted to close the hernial defect, reinforcing the abdominal muscles and reestablishing mechanical functionality of the wall. Meshes for hernia repair are made of synthetic or biological materials exhibiting multiple shapes and configurations. Despite the myriad of devices currently marketed, the search for the ideal mesh continues as, thus far, no device offers optimal tissue repair and restored mechanical performance while minimizing postoperative complications. Additive manufacturing, or 3D-printing, has great potential for biomedical applications. Over the years, different biomaterials with advanced features have been successfully manufactured via 3D-printing for the repair of hard and soft tissues. This technological improvement is of high clinical relevance and paves the way to produce next-generation devices tailored to suit each individual patient. This review focuses on the state of the art and applications of 3D-printing technology for the manufacture of synthetic meshes. We highlight the latest approaches aimed at developing improved bioactive materials (e.g., optimizing antibacterial performance, drug release, or device opacity for contrast imaging). Challenges, limitations, and future perspectives are discussed, offering a comprehensive scenario for the applicability of 3D-printing in hernia repair.

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Experimental and Numerical Analysis of 3D Printed Polymer Tetra-Petal Auxetic Structures under Compression

Applied Sciences ◽

10.3390/app112110362 ◽

2021 ◽

Vol 11 (21) ◽

pp. 10362

Author(s):

Demetris Photiou ◽

Stelios Avraam ◽

Francesco Sillani ◽

Fabrizio Verga ◽

Olivier Jay ◽

...

Keyword(s):

Finite Element ◽

3D Printing ◽

Mechanical Response ◽

Mechanical Performance ◽

Poisson Ratio ◽

Impact Resistance ◽

Experimental Tests ◽

Polymer Materials ◽

Compression Tests ◽

Auxetic Structures

Auxetic structures possess a negative Poisson ratio (ν < 0) as a result of their geometrical configuration, which exhibits enhanced indentation resistance, fracture toughness, and impact resistance, as well as exceptional mechanical response advantages for applications in defense, biomedical, automotive, aerospace, sports, consumer goods, and personal protective equipment sectors. With the advent of additive manufacturing, it has become possible to produce complex shapes with auxetic properties, which could not have been possible with traditional manufacturing. Three-dimensional printing enables easy and precise control of the geometry and material composition of the creation of desirable shapes, providing the opportunity to explore different geometric aspects of auxetic structures with a variety of different materials. This study investigated the geometrical and material combinations that can be jointly tailored to optimize the auxetic effects of 2D and 3D complex structures by integrating design, modelling approaches, 3D printing, and mechanical testing. The simulation-driven design methodology allowed for the identification and creation of optimum auxetic prototype samples manufactured by 3D printing with different polymer materials. Compression tests were performed to characterize the auxetic behavior of the different system configurations. The experimental investigation demonstrated a Poisson’s ration reaching a value of ν = −0.6 for certain shape and material combinations, thus providing support for preliminary finite element studies on unit cells. Finally, based on the experimental tests, 3D finite element models with elastic material formulations were generated to replicate the mechanical performance of the auxetic structures by means of simulations. The findings showed a coherent deformation behavior with experimental measurements and image analysis.

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The influence of 3D printing process parameters on the mechanical performance of PLA polymer and its correlation with hardness

Procedia Manufacturing ◽

10.1016/j.promfg.2021.07.038 ◽

2021 ◽

Vol 54 ◽

pp. 244-249

Author(s):

Muammel M. Hanon ◽

József Dobos ◽

László Zsidai

Keyword(s):

3D Printing ◽

Process Parameters ◽

Mechanical Performance ◽

Printing Process

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Implementation of the emulsification-diffusion method by solvent displacement for polystyrene nanoparticles prepared from recycled material

RSC Advances ◽

10.1039/d0ra07749f ◽

2021 ◽

Vol 11 (4) ◽

pp. 2226-2234

Author(s):

Ana María Pineda-Reyes ◽

Mauricio Hernández Delgado ◽

María de la Luz Zambrano-Zaragoza ◽

Gerardo Leyva-Gómez ◽

Nestor Mendoza-Muñoz ◽

...

Keyword(s):

Expanded Polystyrene ◽

Added Value ◽

Diffusion Method ◽

Displacement Method ◽

Polystyrene Nanoparticles ◽

Solvent Displacement ◽

Recycled Material

A novel solvent emulsification-displacement method for obtaining polystyrene nanoparticles is reported. This process has an added value and can be an alternative for the recycling of expanded polystyrene.

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Long-fibre reinforced polymer composites by 3D printing: influence of nature of reinforcement and processing parameters on mechanical performance

Functional Composite Materials ◽

10.1186/s42252-020-00010-0 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Francis Dantas ◽

Kevin Couling ◽

Gregory J. Gibbons

Keyword(s):

Carbon Fibre ◽

Polymer Composites ◽

Mechanical Performance ◽

Flexural Modulus ◽

Matrix Material ◽

Processing Parameters ◽

Fibre Reinforcement ◽

Reinforced Polymer ◽

Unreinforced Material ◽

Fibre Reinforced Polymer

Abstract The aim of this study was to identify the effect of material type (matrix and reinforcement) and process parameters, on the mechanical properties of 3D Printed long-fibre reinforced polymer composites manufactured using a commercial 3D Printer (Mark Two). The effect of matrix material (Onyx or polyamide), reinforcement type (Carbon, Kevlar®, and HSHT glass), volume of reinforcement, and reinforcement lay-up orientation on both Ultimate Tensile Strength (UTS) and Flexural Modulus were investigated. For Onyx, carbon fibre reinforcement offered the largest increase in both UTS and Flexural Modulus over unreinforced material (1228 ± 19% and 1114 ± 6% respectively). Kevlar® and HSHT also provided improvements but these were less significant. Similarly, for Nylon, the UTS and Flexural Modulus were increased by 1431 ± 56% and 1924 ± 5% by the addition of carbon fibre reinforcement. Statistical analysis indicated that changing the number of layers of reinforcement had the largest impact on both UTS and Flexural Strength, and all parameters were statistically significant.

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A Proof of Concept Study of the Mechanical Behavior of Lattice Structures Used to Design a Shoulder Hemi-Prosthesis

Journal of Engineering and Science in Medical Diagnostics and Therapy ◽

10.1115/1.4051419 ◽

2021 ◽

Author(s):

Marinela Peto ◽

Oscar Aguilar-Rosas ◽

Erick Erick Ramirez-Cedillo ◽

Moises Jimenez ◽

Adriana Hernandez ◽

...

Keyword(s):

Mechanical Behavior ◽

Mechanical Response ◽

Mechanical Performance ◽

Cell Attachment ◽

Lattice Structure ◽

Material Model ◽

Patient Specific ◽

Hexagonal Prism ◽

Lattice Structures ◽

Proof Of Concept

Abstract Lattice structures offer great benefits when employed in medical implants for cell attachment and growth (osseointegration), minimization of stress shielding phenomena, and weight reduction. This study is focused on a proof of concept for developing a generic shoulder hemi-prosthesis, from a patient-specific case of a 46 years old male with a tumor on the upper part of his humerus. A personalized biomodel was designed and a lattice structure was integrated in its middle portion, to lighten weight without affecting humerus’ mechanical response. To select the most appropriate lattice structure, three different configurations were initially tested: Tetrahedral Vertex Centroid (TVC), Hexagonal Prism Vertex Centroid (HPVC), and Cubic Diamond (CD). They were fabricated in resin by digital light processing and its mechanical behavior was studied via compression testing and finite element modeling (FEM). The selected structure according to the results was the HPVC, which was integrated in a digital twin of the biomodel to validate its mechanical performance through FEM but substituting the bone material model with a biocompatible titanium alloy (Ti6Al4V) suitable for prostheses fabrication. Results of the simulation showed acceptable levels of Von Mises stresses (325 MPa max.), below the elastic limit of the titanium alloys, and a better response (52 MPa max.) in a model with equivalent elastic properties, with stress performance in the same order of magnitude than the showed in bone’s material model.

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