Additive Manufacturing of (Bio) Polymeric Materials

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Processing and Engineering".

Deadline for manuscript submissions: 25 May 2024 | Viewed by 18615

Special Issue Editors


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Guest Editor
Department of Automotive Engineering, Transilvania University of Brasov, Brașov, Romania
Interests: polymer composites; coatings; composite micromechanics; mechanical/thermal/dynamic-mechanical/electrical/optical properties

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Guest Editor
Department of Mechanical Engineering and Materials, Universitat Politècnica de València (UPV), 03801 Alcoy, Spain
Interests: additive printing; injection; polymer and polymer composites; material characterization; FEM simulation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

You are invited to submit to this Special Issue of Polymers. We are looking for research papers, reviews or short communications covering topics on the additive manufacturing of (bio)polymers and composites thereof. Topics of particular interest include but are not limited to:

  • The synthesis and development of novel (bio)polymer formulations suitable for a wide range of additive processes, such as: fused deposition modeling (FDM), selective laser sintering (SLS), direct light processing (DLP), laminated object manufacturing (LOM), etc.;
  • Additively tailored synthetic/natural filler-reinforced composites;
  • (Bio)polymer and/or composite characterization and performance (e.g., mechanical, thermal, dynamic-mechanical, electrical, chemical, biological, optical, etc.);
  • The relationship between process–structure–material properties;
  • The optimization of process parameters;
  • The modeling and simulation of processes and materials;

Application-driven solutions (e.g., energy storage/harvesting, biomedical, engineering, robotics, optoelectronics, sensors, etc.).

Prof. Dr. Dana Luca Motoc
Dr. Santiago Ferrandiz
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • additive manufacturing
  • (bio)polymers
  • (bio)polymer-based composites
  • material characterization
  • modeling and simulation
  • applications

Published Papers (10 papers)

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Research

24 pages, 14260 KiB  
Article
A Comparative Investigation of the Reliability of Biodegradable Components Produced through Additive Manufacturing Technology
by Amged ElHassan, Waleed Ahmed and Essam Zaneldin
Polymers 2024, 16(5), 615; https://doi.org/10.3390/polym16050615 - 23 Feb 2024
Viewed by 626
Abstract
Using the linear elastic finite element method, we investigated how defects significantly influence the integrity of 3D-printed parts made from biodegradable material by experimental techniques and numerical simulations. A defective flaw was incorporated into the tensile test dog-bone sample using Computer-Aided Design and [...] Read more.
Using the linear elastic finite element method, we investigated how defects significantly influence the integrity of 3D-printed parts made from biodegradable material by experimental techniques and numerical simulations. A defective flaw was incorporated into the tensile test dog-bone sample using Computer-Aided Design and processed by slicing software. Three distinct raster angles examine two sets of samples, one featuring intact specimens and the other with the introduced defects. An open-source 3D printer was used to fabricate both sets of samples, utilizing biodegradable PLA material. In finite element analysis, we employed a highly detailed model that precisely accounted for the geometry and dimensions of the extruded 3D-printed filament, accurately replicating the actual configuration of the 3D-printed samples to an extent. Our study involved a thorough comparative analysis between the experimental results and the FEA simulations. Our findings uncovered a consistent trend for the intact and defective samples under tensile load. Specifically, in the intact case, the samples with a zero-degree raster orientation presented the highest resistance to failure and displayed minimal elongation. Remarkably, these conclusions paralleled our observations of the defective samples as well. Finite element analysis revealed that the stresses, including Principal, Max shear, and Von Mises, were remarkably higher at the 3D-printed samples’ outer surface than the inner layers, reflecting that the failure starts at the outer surface since they exceeded the theoretical values, indicating a significant discrepancy between the simulated and anticipated values. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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20 pages, 15426 KiB  
Article
Sound Absorption Performance and Mechanical Properties of the 3D-Printed Bio-Degradable Panels
by Sebastian-Marian Zaharia, Mihai Alin Pop, Mihaela Cosnita, Cătălin Croitoru, Simona Matei and Cosmin Spîrchez
Polymers 2023, 15(18), 3695; https://doi.org/10.3390/polym15183695 - 07 Sep 2023
Cited by 3 | Viewed by 1518
Abstract
The 3D printing process allows complex structures to be obtained with low environmental impact using biodegradable materials. This work aims to develop and acoustically characterize 3D-printed panels using three types of materials, each manufactured at five infill densities (20%, 40%, 60%, 80% and [...] Read more.
The 3D printing process allows complex structures to be obtained with low environmental impact using biodegradable materials. This work aims to develop and acoustically characterize 3D-printed panels using three types of materials, each manufactured at five infill densities (20%, 40%, 60%, 80% and 100%) with three internal configurations based on circular, triangular, and corrugated profiles. The highest absorption coefficient values (α = 0.93) were obtained from the acoustic tests for the polylactic acid material with ground birch wood particles in the triangular configuration with an infill density of 40%. The triangular profile showed the best acoustic performance for the three types of materials analysed and, from the point of view of the mechanical tests, it was highlighted that the same triangular configuration presented the highest resistance both to compression (40 MPa) and to three-point bending (50 MPa). The 40% and 60% infill density gave the highest absorption coefficient values regardless of the material analyzed. The mechanical tests for compression and three-point bending showed higher strength values for samples manufactured from simple polylactic acid filament compared to samples manufactured from ground wood particles. The standard defects of 3D printing and the failure modes of the interior configurations of the 3D-printed samples could be observed from the microscopic analysis of the panels. Based on the acoustic results and the determined mechanical properties, one application area for these types of 3D-printed panels could be the automotive and aerospace industries. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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18 pages, 33150 KiB  
Article
Additive Manufacturing of Biodegradable Hemp-Reinforced Polybutylene Succinate (PBS) and Its Mechanical Characterization
by Antonia Dönitz, Anton Köllner, Tim Richter, Oliver Löschke, Dietmar Auhl and Christina Völlmecke
Polymers 2023, 15(10), 2271; https://doi.org/10.3390/polym15102271 - 11 May 2023
Cited by 6 | Viewed by 2083
Abstract
The additive manufacturing of natural fibre-reinforced polymers is a pivotal method in developing sustainable engineering solutions. Using the fused filament fabrication method, the current study investigates the additive manufacturing of hemp-reinforced polybutylene succinate (PBS) alongside its mechanical characterization. Two types of hemp reinforcement [...] Read more.
The additive manufacturing of natural fibre-reinforced polymers is a pivotal method in developing sustainable engineering solutions. Using the fused filament fabrication method, the current study investigates the additive manufacturing of hemp-reinforced polybutylene succinate (PBS) alongside its mechanical characterization. Two types of hemp reinforcement are considered: short fibres (max. length smaller than 2 mm) and long fibres (max. length smaller than 10 mm), which are compared against non-reinforced (pure) PBS. A detailed analysis is performed regarding the determination of suitable 3D printing parameters (overlap, temperature, nozzle diameter). In a comprehensive experimental study, additionally to general analyses regarding the influence of hemp reinforcement on the mechanical behaviour, the effect of printing parameters is determined and discussed. Introducing an overlap in the additive manufacturing of the specimens results in improved mechanical performance. The study highlights that the Young’s modulus of PBS can be improved by 63% by introducing hemp fibres in conjunction with overlap. In contrast, hemp fibre reinforcement reduces the tensile strength of PBS, while this effect is less pronounced considering overlap in the additive manufacturing process. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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14 pages, 3303 KiB  
Article
High Tg, Bio-Based Isosorbide Methacrylate Resin Systems for Vat Photopolymerization
by Xi Chu, Jianwei Tu, Heather R. Berensmann, John J. La Scala and Giuseppe R. Palmese
Polymers 2023, 15(9), 2007; https://doi.org/10.3390/polym15092007 - 24 Apr 2023
Cited by 2 | Viewed by 1896
Abstract
The use of isosorbide-derived polymers has garnered significant attention in recent decades as a high-performance, renewable material sourced from biomass. Of particular interest is isosorbide methacrylate, which possesses low viscosity (<500 cps), high thermal properties (Tg ≈ 220 °C), and high [...] Read more.
The use of isosorbide-derived polymers has garnered significant attention in recent decades as a high-performance, renewable material sourced from biomass. Of particular interest is isosorbide methacrylate, which possesses low viscosity (<500 cps), high thermal properties (Tg ≈ 220 °C), and high modulus (>4 GPa). These characteristics present a promising opportunity to replace BPA-derived methacrylate compounds in various applications. This investigation aims to synthesize and characterize isosorbide-based low-viscosity resin systems for 3D printing. The resin blends are composed of isosorbide methacrylate and two bio-renewable methacrylates, furfuryl methacrylate (FM) and bis-hydroxymethyl-furan methacrylate (BHMF-M), polymerized through a digital light processing (DLP) technique. The addition of the bio-based co-monomers serves to enhance the fracture toughness of the brittle isosorbide methacrylate crosslinked homopolymer (GIc = 37 J/m2). The resulting polymers exhibit Tg values greater than 200 °C and GIc around 100 J/m2. These resin systems hold potential for imparting high bio-based content to polymers used in additive manufacturing for high-performance applications. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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17 pages, 2649 KiB  
Article
Methods to Reduce Energy and Polymer Consumption for Fused Filament Fabrication 3D Printing
by Owen James Harding, Christian Andrew Griffiths, Andrew Rees and Dimitrios Pletsas
Polymers 2023, 15(8), 1874; https://doi.org/10.3390/polym15081874 - 13 Apr 2023
Cited by 4 | Viewed by 1856
Abstract
Fused Filament Fabrication (FFF) 3D printing is an additive technology used to manufacture parts. Used in the engineering industry for prototyping polymetric parts, this disruptive technology has been adopted commercially and there are affordable printers on the market that allow for at-home printing. [...] Read more.
Fused Filament Fabrication (FFF) 3D printing is an additive technology used to manufacture parts. Used in the engineering industry for prototyping polymetric parts, this disruptive technology has been adopted commercially and there are affordable printers on the market that allow for at-home printing. This paper examines six methods of reducing the energy and material consumption of 3D printing. Using different commercial printers, each approach was investigated experimentally, and the potential savings were quantified. The modification most effective at reducing energy consumption was the hot-end insulation, with savings of 33.8–30.63%, followed by the sealed enclosure, yielding an average power reduction of 18%. For material, the most influential change was noted using ‘lightning infill’, reducing material consumption by 51%. The methodology includes a combined energy- and material-saving approach in the production of a referenceable ‘Utah Teapot’ sample object. Using combined techniques on the Utah Teapot print, the material consumption was reduced by values between 55.8% and 56.4%, and power consumption was reduced by 29% to 38%. The implementation of a data-logging system allowed us to identify significant thermal management and material usage opportunities to minimise power consumption, providing solutions for a more positive impact on the sustainable manufacturing of 3D printed parts. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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11 pages, 1783 KiB  
Article
The Effects of Different Molding Orientations, Highly Accelerated Aging, and Water Absorption on the Flexural Strength of Polyether Ether Ketone (PEEK) Fabricated by Fused Deposition Modeling
by Daisuke Miura, Yoshiki Ishida and Akikazu Shinya
Polymers 2023, 15(7), 1602; https://doi.org/10.3390/polym15071602 - 23 Mar 2023
Cited by 3 | Viewed by 1121
Abstract
Rising prices are currently a problem in the world. In particular, the abnormal increases in the price of metals, which are often used in dental prosthetics, have increased the burden of dental costs on the public. There is therefore an urgent need to [...] Read more.
Rising prices are currently a problem in the world. In particular, the abnormal increases in the price of metals, which are often used in dental prosthetics, have increased the burden of dental costs on the public. There is therefore an urgent need to develop prosthetic devices made from materials that are not affected by the global situation and that have excellent biocompatibility and mechanical properties comparable to those of metals. Polyether ether ketone (PEEK) is a promising alternative to metal in dentistry. This study compared the effects of different molding orientations, highly accelerated aging, and water absorption on the flexural strength of PEEK fabricated by fused deposition modeling (FDM) and examined its potential for dental applications. The flexural strength of PEEK stacked at 0° to the molding stage (0° PF), with and without highly accelerated aging, was significantly greater than for the other molding orientations. As with PD, the maximum test load for 0° PF was measured without fracture. PEEK stacked at 45° (45° PF) and 90° (90° PF) to the molding stage easily fractured, as the applied load pulled the stacked layers. No statistically significant difference was found between the flexural strength of 45° PF and 90° PF. The flexural strength decreased under all conditions due to defects in the crystal structure of PEEK caused by highly accelerated aging. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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12 pages, 4088 KiB  
Article
Impact of In-Soil Ageing Effect on PLA Printed Parts Tensile Properties
by Ana P. Valerga, Severo R. Fernandez-Vidal and Franck Girot
Polymers 2023, 15(4), 862; https://doi.org/10.3390/polym15040862 - 09 Feb 2023
Cited by 1 | Viewed by 1108
Abstract
Material extrusion (MEX), more commonly known as fused deposition modelling (FDM/FFF), is one of the most widely used techniques in polymeric Additive Manufacturing (AM). This technology is increasingly present in fields such as engineering and medicine with polymeric materials, including additives of many [...] Read more.
Material extrusion (MEX), more commonly known as fused deposition modelling (FDM/FFF), is one of the most widely used techniques in polymeric Additive Manufacturing (AM). This technology is increasingly present in fields such as engineering and medicine with polymeric materials, including additives of many types. Polylactic acid polymer (PLA) is one of the most widely used materials currently on the market for MEX technology. In addition to its ease of printing, it is a plastic of natural origin, biodegradable and supplants petroleum derivatives in many applications. However, the effect of ageing on the mechanical properties of PLA are still to be evaluated and understood. The main objective of this work is to investigate the effects of ageing of PLA samples on the tensile properties. To investigate the effect of ageing, the samples were tested periodically after exposure to fertilized soil for a period up to 6 months. In addition, some of the samples were chemically pre-treated to improve the surface quality, and the effect of ageing on the treated and untreated samples was also evaluated. This study showed that ultimate strength decreased with ageing from 46 to 36 MPa (22%), and it increased with treatment time in high percentages (even 40%) depending on the time of immersion in the solvent. However, this effect of the chemical treatment gradually disappeared, with the exception of the surface improvement obtained. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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22 pages, 6614 KiB  
Article
Functional Filaments: Creating and Degrading pH-Indicating PLA Filaments for 3D Printing
by Shelbie A. Legett, John R. Stockdale, Xavier Torres, Chris M. Yeager, Adam Pacheco and Andrea Labouriau
Polymers 2023, 15(2), 436; https://doi.org/10.3390/polym15020436 - 13 Jan 2023
Cited by 5 | Viewed by 2808
Abstract
With the rapid pace of advancements in additive manufacturing and techniques such as fused filament fabrication (FFF), the feedstocks used in these techniques should advance as well. While available filaments can be used to print highly customizable parts, the creation of the end [...] Read more.
With the rapid pace of advancements in additive manufacturing and techniques such as fused filament fabrication (FFF), the feedstocks used in these techniques should advance as well. While available filaments can be used to print highly customizable parts, the creation of the end part is often the only function of a given feedstock. In this study, novel FFF filaments with inherent environmental sensing functionalities were created by melt-blending poly(lactic acid) (PLA), poly(ethylene glycol) (PEG), and pH indicator powders (bromothymol blue, phenolphthalein, and thymol blue). The new PLA-PEG-indicator filaments were universally more crystalline than the PLA-only filaments (33–41% vs. 19% crystallinity), but changes in thermal stability and mechanical characteristics depended upon the indicator used; filaments containing bromothymol blue and thymol blue were more thermally stable, had higher tensile strength, and were less ductile than PLA-only filaments, while filaments containing phenolphthalein were less thermally stable, had lower tensile strength, and were more ductile. When the indicator-filled filaments were exposed to acidic, neutral, and basic solutions, all filaments functioned as effective pH sensors, though the bromothymol blue-containing filament was only successful as a base indicator. The biodegradability of the new filaments was evaluated by characterizing filament samples after aging in soil and soil slurry mixtures; the amount of physical deterioration and changes in filament crystallinity suggested that the bromothymol blue filament degraded faster than PLA-only filaments, while the phenolphthalein and thymol blue filaments saw decreases in degradation rates. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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19 pages, 10162 KiB  
Article
Deformation Behavior of 3D Printed Auxetic Structures of Thermoplastic Polymers: PLA, PBAT, and Blends
by Jonas Hufert, Axel Grebhardt, Yanling Schneider, Christian Bonten and Siegfried Schmauder
Polymers 2023, 15(2), 389; https://doi.org/10.3390/polym15020389 - 11 Jan 2023
Cited by 3 | Viewed by 2212
Abstract
Auxetic structures have a negative Poisson’s ratio and therefore expand transversely to the direction of loading instead of tapering. This unique behavior is not caused by the materials used, but by the structure, and thus offers completely new functionalities and design possibilities. As [...] Read more.
Auxetic structures have a negative Poisson’s ratio and therefore expand transversely to the direction of loading instead of tapering. This unique behavior is not caused by the materials used, but by the structure, and thus offers completely new functionalities and design possibilities. As a rule, auxetic structures have a very complex geometry, which makes cost-effective production possible only by means of additive manufacturing processes. Due to the high design freedom of the strand deposition method, it makes sense to manufacture auxetic structures using this process. Therefore, in this project, polylactide acid (PLA), polybutylene adipate terephthalate (PBAT), and blends of the two polymers were produced and characterized. Filaments of the two polymers and a blend were extruded, processed into auxetic structures by strand deposition process (SDP), and investigated for their properties, primarily their Poisson’s ratio. The Poisson’s ratio was determined and the influence of the material on it was identified. A specific number of 5 × 5 unit cells has been found to be ideal for investigation. Dual printed specimens showed a similar auxetic behavior as the specimens made of pure PBAT. Likewise, multiple loading and unloading of the structure is possible. Furthermore, in-situ computed tomography revealed the detailed characterization of the initial state, including the warpage of the structures, damage, and traced auxetic behavior in detail. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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16 pages, 5193 KiB  
Article
Fused Filament Fabrication of Bio-Based Polyether-Block-Amide Polymers (PEBAX) and Their Related Properties
by Matthias Schär, Lucian Zweifel, Delal Arslan, Stefan Grieder, Christoph Maurer and Christian Brauner
Polymers 2022, 14(23), 5092; https://doi.org/10.3390/polym14235092 - 23 Nov 2022
Cited by 4 | Viewed by 2357
Abstract
This paper describes the application of poly(ether-block-amide) polymers, so-called Pebax, in fused filament fabrication (FFF). Pebax® is a thermoplastic elastomer (TPE), a copolymer based on rigid polyamide and soft polyether blocks. By variation of the blocks, unique properties such as soft or [...] Read more.
This paper describes the application of poly(ether-block-amide) polymers, so-called Pebax, in fused filament fabrication (FFF). Pebax® is a thermoplastic elastomer (TPE), a copolymer based on rigid polyamide and soft polyether blocks. By variation of the blocks, unique properties such as soft or rigid behaviour are tailored without additional additives and plasticisers. Pebax®Rnew® polyamide blocks are bio-based and made from castor beans that allow the design of sustainable applications. In this study, two types of Pebax were selected, processing parameters were characterised, filaments were extruded and applied to FFF printing, and the final mechanical characteristics were determined. Both types were suitable for FFF processing with improved process stability due to less shear thinning and good mechanical performance. The connection strength between the grades was also described in the design context for complex parts with tailored soft or hard regions. Combining the two materials in one design is a promising concept, and the adhesion strength is close to the strength in the Z-direction of the flexible Pebax®Rnew®35R53 grade. Full article
(This article belongs to the Special Issue Additive Manufacturing of (Bio) Polymeric Materials)
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