Polymers

Research

13 pages, 4497 KiB

Open AccessArticle

Fabrication of Fish Scale-Based Gelatin Methacryloyl for 3D Bioprinting Application

by Kitipong Pasanaphong, Danai Pukasamsombut, Sani Boonyagul, Sukanya Pengpanich, Tulyapruek Tawonsawatruk, Danuphat Wilairatanarporn, Kittisak Jantanasakulwong, Pornchai Rachtanapun, Ruedee Hemstapat, Sutee Wangtueai and Nuttapol Tanadchangsaeng

Polymers 2024, 16(3), 418; https://doi.org/10.3390/polym16030418 - 1 Feb 2024

Viewed by 1157

Abstract

Gelatin methacryloyl (GelMA) is an ideal bioink that is commonly used in bioprinting. GelMA is primarily acquired from mammalian sources; however, the required amount makes the market price extremely high. Since garbage overflow is currently a global issue, we hypothesized that fish scales [...] Read more.

Gelatin methacryloyl (GelMA) is an ideal bioink that is commonly used in bioprinting. GelMA is primarily acquired from mammalian sources; however, the required amount makes the market price extremely high. Since garbage overflow is currently a global issue, we hypothesized that fish scales left over from the seafood industry could be used to synthesize GelMA. Clinically, the utilization of fish products is more advantageous than those derived from mammals as they lower the possibility of disease transmission from mammals to humans and are permissible for practitioners of all major religions. In this study, we used gelatin extracted from fish scales and conventional GelMA synthesis methods to synthesize GelMA, then tested it at different concentrations in order to evaluated and compared the mechanical properties and cell responses. The fish scale GelMA had a printing accuracy of 97%, a swelling ratio of 482%, and a compressive strength of about 85 kPa at a 10% w/v GelMA concentration. Keratinocyte cells (HaCaT cells) were bioprinted with the GelMA bioink to assess cell viability and proliferation. After 72 h of culture, the number of cells increased by almost three-fold compared to 24 h, as indicated by many fluorescent cell nuclei. Based on this finding, it is possible to use fish scale GelMA bioink as a scaffold to support and enhance cell viability and proliferation. Therefore, we conclude that fish scale-based GelMA has the potential to be used as an alternative biomaterial for a wide range of biomedical applications. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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15 pages, 5644 KiB

Open AccessArticle

Interplay between Shelf Life and Printability of Silica-Filled Suspensions

by Xavier M. Torres, John R. Stockdale, Santosh Adhikari, Shelbie A. Legett, Adam Pacheco, Jesus A. Guajardo and Andrea Labouriau

Polymers 2023, 15(21), 4334; https://doi.org/10.3390/polym15214334 - 6 Nov 2023

Cited by 1 | Viewed by 935

Abstract

Although fumed silica/siloxane suspensions are commonly employed in additive manufacturing technology, the interplay between shelf life, storage conditions, and printability has yet to be explored. In this work, direct ink writing (DIW) was used to print unique three-dimensional structures that required suspensions to [...] Read more.

Although fumed silica/siloxane suspensions are commonly employed in additive manufacturing technology, the interplay between shelf life, storage conditions, and printability has yet to be explored. In this work, direct ink writing (DIW) was used to print unique three-dimensional structures that required suspensions to retain shape and form while being printed onto a substrate. Suspensions containing varying concentrations of hydrophobic and hydrophilic silica were formulated and evaluated over a time span of thirty days. Storage conditions included low (8%) and high (50%) relative humidity and temperatures ranging from 4 °C to 25 °C. The shelf life of the suspensions was examined by comparing the print quality of pristine and aged samples via rheology, optical microscopy, and mechanical testing. Results showed a significant decrease in printability over time for suspensions containing hydrophilic fumed silica, whereas the printability of suspensions containing hydrophobic fumed silica remained largely unchanged after storage. The findings in this work established the following recommendations for extending the shelf life and printability of suspensions commonly used in DIW technology: (1) higher fumed silica concentrations, (2) low humidity and low temperature storage environments, and (3) the use of hydrophobic fumed silica instead of hydrophilic fumed silica. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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7 pages, 1534 KiB

Open AccessCommunication

Enhancing the Piezoelectric Properties of 3D Printed PVDF Using Concurrent Torsional Shear Strain

by Pu Han, Alireza Tofangchi, Derek Carr, Sihan Zhang and Keng Hsu

Polymers 2023, 15(21), 4204; https://doi.org/10.3390/polym15214204 - 24 Oct 2023

Viewed by 1210

Abstract

Extrusion-based polymer 3D printing induces shear strains within the material, influencing its rheological and mechanical properties. In materials like polyvinylidene difluoride (PVDF), these strains stretch polymer chains, leading to increased crystallinity and improved piezoelectric properties. This study demonstrates a 400% enhancement in the [...] Read more.

Extrusion-based polymer 3D printing induces shear strains within the material, influencing its rheological and mechanical properties. In materials like polyvinylidene difluoride (PVDF), these strains stretch polymer chains, leading to increased crystallinity and improved piezoelectric properties. This study demonstrates a 400% enhancement in the piezoelectric property of extrusion-printed PVDF by introducing additional shear strains during the printing process. The continuous torsional shear strains, imposed via a rotating extrusion nozzle, results in additional crystalline β-phases, directly impacting the piezoelectric behavior of the printed parts. The effect of the nozzle’s rotational speed on the amount of β-phase formation is characterized using FTIR. This research introduces a new direction in the development of polymer and composite 3D printing, where in-process shear strains are used to control the alignment of polymer chains and/or in-fill phases and the overall properties of printed parts. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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13 pages, 6269 KiB

Open AccessArticle

A Printing Strategy for Embedding Conductor Paths into FFF Printed Parts

by Timo Banko, Stefan Grünwald, Rainer Kronberger and Hermann Seitz

Polymers 2023, 15(17), 3498; https://doi.org/10.3390/polym15173498 - 22 Aug 2023

Viewed by 842

Abstract

A novel approach to manufacture components with integrated conductor paths involves embedding and sintering an isotropic conductive adhesive (ICA) during fused filament fabrication (FFF). However, the molten plastic is deposited directly onto the adhesive path which causes an inhomogeneous displacement of the uncured [...] Read more.

A novel approach to manufacture components with integrated conductor paths involves embedding and sintering an isotropic conductive adhesive (ICA) during fused filament fabrication (FFF). However, the molten plastic is deposited directly onto the adhesive path which causes an inhomogeneous displacement of the uncured ICA. This paper presents a 3D printing strategy to achieve a homogeneous cross-section of the conductor path. The approach involves embedding the ICA into a printed groove and sealing it with a wide extruded plastic strand. Three parameter studies are conducted to obtain a consistent cavity for uniform formation of the ICA path. Specimens made of polylactic acid (PLA) with embedded ICA paths are printed and evaluated. The optimal parameters include a groove printed with a layer height of 0.1 mm, depth of 0.4 mm, and sealed with a PLA strand of 700 µm diameter. This resulted in a conductor path with a homogeneous cross-section, measuring 660 µm ± 22 µm in width (relative standard deviation: 3.3%) and a cross-sectional area of 0.108 mm² ± 0.008 mm² (relative standard deviation 7.2%). This is the first study to demonstrate the successful implementation of a printing strategy for embedding conductive traces with a homogeneous cross-sectional area in FFF 3D printing. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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13 pages, 6228 KiB

Open AccessArticle

Environmental Stability of Additively Manufactured Thermoplastic Polyamide Composites

by Michael J. Imburgia, Jessica L. Faust, Johan Ospina Buitrago, Rachael E. Enfield and Joseph D. Roy-Mayhew

Polymers 2023, 15(16), 3385; https://doi.org/10.3390/polym15163385 - 12 Aug 2023

Viewed by 1462

Abstract

As the adoption of additive manufacturing technologies for end-use parts continues to progress, the evaluation of environmental durability is essential for the qualification of manufactured articles in industries such as automotive, aerospace, and electrical. This study explores the effects of UV and water-spray [...] Read more.

As the adoption of additive manufacturing technologies for end-use parts continues to progress, the evaluation of environmental durability is essential for the qualification of manufactured articles in industries such as automotive, aerospace, and electrical. This study explores the effects of UV and water-spray exposure on the mechanical properties of an additively manufactured polyamide 6 blend reinforced with short carbon fiber and continuous carbon fiber. Fused-filament-fabrication-printed test samples were exposed to a Xenon-arc UV source following ASTM G155 Cycle 1 conditions for a duration of 1000 h. Tensile, flexural, and Izod impact tests were performed on exposed and unexposed test samples. While Exposed tensile and flexural samples maintained their strength (84–100% and 88–100%, of Control samples, respectively), Izod impact strength increased (104–201% of Controls). This study also examines the influence of coatings and finds that samples coated with Krylon^® Fusion All-In-One^® and JetFlex^® Polyurethane Primer maintain similar mechanical properties and exhibit a better visual appearance as compared to uncoated, exposed samples. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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20 pages, 12736 KiB

Open AccessArticle

Effects of Annealing for Strength Enhancement of FDM 3D-Printed ABS Reinforced with Recycled Carbon Fiber

by Wonseok Seok, Euysik Jeon and Youngshin Kim

Polymers 2023, 15(14), 3110; https://doi.org/10.3390/polym15143110 - 21 Jul 2023

Cited by 5 | Viewed by 1679

Abstract

This study investigates the effect of annealing on the mechanical properties of fused deposition modeling (FDM) 3D-printed recycled carbon fiber (rCF)-reinforced composites. In this study, filaments for FDM 3D printers are self-fabricated from pure acrylonitrile butadiene styrene (ABS) and ABS reinforced with fiber [...] Read more.

This study investigates the effect of annealing on the mechanical properties of fused deposition modeling (FDM) 3D-printed recycled carbon fiber (rCF)-reinforced composites. In this study, filaments for FDM 3D printers are self-fabricated from pure acrylonitrile butadiene styrene (ABS) and ABS reinforced with fiber content of 10 wt% and 20 wt% rCF. This study explores the tensile and flexural properties as a function of the annealing temperature and time for the three different fiber content values. In addition, dimensional measurements of the shape changes are performed to determine the suitability of applying annealing in practical manufacturing processes. The results show that annealing improves the mechanical properties by narrowing the voids between the beads, which occur during the FDM process, and by reducing the gaps between the fibers and polymer. Following annealing, the largest tensile and flexural strength improvements are 12.64% and 42.33%, respectively, for the 20 wt% rCF content samples. Moreover, compared with the pure ABS samples, the annealing effect improves the mechanical properties of the rCF-reinforced samples more effectively, and they have higher dimensional stability, indicating their suitability for annealing. These results are expected to expand the application fields of rCF and greatly increase the potential use of FDM-printed parts. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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15 pages, 2596 KiB

Open AccessArticle

Advancements in Functionally Graded Polyether Ether Ketone Components: Design, Manufacturing, and Characterisation Using a Modified 3D Printer

by Eric McNiffe, Tobias Ritter, Tom Higgins, Omid Sam-Daliri, Tomas Flanagan, Michael Walls, Pouyan Ghabezi, William Finnegan, Sinéad Mitchell and Noel M. Harrison

Polymers 2023, 15(14), 2992; https://doi.org/10.3390/polym15142992 - 10 Jul 2023

Cited by 12 | Viewed by 1766

Abstract

Functionally Graded Materials represent the next generation of engineering design for metal and plastic components. In this research, a specifically modified and optimised 3D printer was used to manufacture functionally graded polyether ether ketone components. This paper details the design and manufacturing methodologies [...] Read more.

Functionally Graded Materials represent the next generation of engineering design for metal and plastic components. In this research, a specifically modified and optimised 3D printer was used to manufacture functionally graded polyether ether ketone components. This paper details the design and manufacturing methodologies used in the development of a polyether ether ketone printer capable of producing functionally graded materials through the manipulation of microstructure. The interaction of individually deposited beads of material during the printing process was investigated using scanning electron microscopy, to observe and quantify the porosity levels and interlayer bonding strength, which affects the quality of the final parts. Specimens were produced under varying process conditions and tested to characterise the influence of the process conditions on the resulting material properties. The specimens printed at high enclosure temperatures exhibited greater strength than parts printed without the active addition of heat, due to improved bond formation between individual layers of the print and a large degree of crystallinity through maintenance at these elevated temperatures. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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17 pages, 3550 KiB

Open AccessArticle

Physicochemical Properties of 3D-Printed Polylactic Acid/Hydroxyapatite Scaffolds

by Sara Pérez-Davila, Natalia Garrido-Gulías, Laura González-Rodríguez, Miriam López-Álvarez, Julia Serra, José Eugenio López-Periago and Pío González

Polymers 2023, 15(13), 2849; https://doi.org/10.3390/polym15132849 - 28 Jun 2023

Cited by 3 | Viewed by 1432

Abstract

The reconstruction or regeneration of damaged bone tissue is one of the challenges of orthopedic surgery and tissue engineering. Among all strategies investigated, additive manufacturing by fused deposition modeling (3D-FDM printing) opens the possibility to obtain patient-specific scaffolds with controlled architectures. The present [...] Read more.

The reconstruction or regeneration of damaged bone tissue is one of the challenges of orthopedic surgery and tissue engineering. Among all strategies investigated, additive manufacturing by fused deposition modeling (3D-FDM printing) opens the possibility to obtain patient-specific scaffolds with controlled architectures. The present work evaluates in depth 3D direct printing, avoiding the need for a pre-fabricated filament, to obtain bone-related scaffolds from direct mixtures of polylactic acid (PLA) and hydroxyapatite (HA). For it, a systematic physicochemical characterization (SEM-EDS, FT-Raman, XRD, micro-CT and nanoindentation) was performed, using different PLA/HA ratios and percentages of infill. Results prove the versatility of this methodology with an efficient HA incorporation in the 3D-printed scaffolds up to 13 wt.% of the total mass and a uniform distribution of the HA particles in the scaffold at the macro level, both longitudinal and cross sections. Moreover, an exponential distribution of the HA particles from the surface toward the interior of the biocomposite cord (micro level), within the first 80 µm (10% of the entire cord diameter), is also confirmed, providing the scaffold with surface roughness and higher bioavailability. In relation to the pores, they can range in size from 250 to 850 µm and can represent a percentage, in relation to the total volume of the scaffold, from 24% up to 76%. The mechanical properties indicate an increase in Young’s modulus with the HA content of up to ~50%, compared to the scaffolds without HA. Finally, the in vitro evaluation confirms MG63 cell proliferation on the 3D-printed PLA/HA scaffolds after up to 21 days of incubation. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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14 pages, 2461 KiB

Open AccessArticle

Three-Dimensionally Printed Expandable Structural Electronics Via Multi-Material Printing Room-Temperature-Vulcanizing (RTV) Silicone/Silver Flake Composite and RTV

by Ju-Yong Lee, Min-Ha Oh, Joo-Hyeon Park, Se-Hun Kang and Seung-Kyun Kang

Polymers 2023, 15(9), 2003; https://doi.org/10.3390/polym15092003 - 23 Apr 2023

Cited by 2 | Viewed by 2254

Abstract

Three-dimensional (3D) printing has various applications in many fields, such as soft electronics, robotic systems, biomedical implants, and the recycling of thermoplastic composite materials. Three-dimensional printing, which was only previously available for prototyping, is currently evolving into a technology that can be utilized [...] Read more.

Three-dimensional (3D) printing has various applications in many fields, such as soft electronics, robotic systems, biomedical implants, and the recycling of thermoplastic composite materials. Three-dimensional printing, which was only previously available for prototyping, is currently evolving into a technology that can be utilized by integrating various materials into customized structures in a single step. Owing to the aforementioned advantages, multi-functional 3D objects or multi-material-designed 3D patterns can be fabricated. In this study, we designed and fabricated 3D-printed expandable structural electronics in a substrateless auxetic pattern that can be adapted to multi-dimensional deformation. The printability and electrical conductivity of a stretchable conductor (Ag-RTV composite) were optimized by incorporating a lubricant. The Ag-RTV and RTV were printed in the form of conducting voxels and frame voxels through multi-nozzle printing and were arranged in a negative Poisson’s ratio pattern with a missing rib structure, to realize an expandable passive component. In addition, the expandable structural electronics were embedded in a soft actuator via one-step printing, confirming the possibility of fabricating stable interconnections in expanding deformation via a missing rib pattern. Full article

(This article belongs to the Special Issue 3D Printing of Polymer-Based Composite Materials)

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