3D Printing Polymer: Processing and Fabrication

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

Deadline for manuscript submissions: closed (25 May 2024) | Viewed by 12450

Special Issue Editors

Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
Interests: 3D printing; molecular pharmaceutics and drug delivery; polymer; green polymers; sustainability

E-Mail Website
Guest Editor
Department of Materials Science and Engineering, University of Sheffield, Sheffield S3 7HQ, UK
Interests: biomaterials; additive manufacturing; tissue engineering; regenerative medicine; biopolymers; biosensors
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The 3D printing of polymers is being increasingly applied in the pharmaceutical, aerospace, and architectural industries and for the fabrication of sensors and other devices. This technology uses a bottom-up approach to create 3D objects by additively adding materials layer-by-layer (LBL), thus reducing waste while producing a high degree of geometric accuracy. However, most 3D-printed polymer models are still used as conceptual prototypes rather than functional components. This can be due to a lack of strength and functionality as fully functional and load-bearing parts. A potential solution is combining polymers with additional functional ingredients such as nanoparticles, materials derived from nature, and biomedically functional materials (e.g., peptides, enzymes) to achieve a multi-ingredient polymer system with a higher degree of suitable mechanical and functional properties.

This Special Issue welcomes papers on a wide variety of topics in polymer processing and fabrication with a particular emphasis on 3D printing (Additive Manufacturing) and research that supports relevant fundamental advances.

Dr. Yu Zhang
Dr. David Alexander Gregory
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.

Published Papers (9 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Jump to: Review

10 pages, 837 KiB  
Article
Effect of Different Post-Curing Methods on the Degree of Conversion of 3D-Printed Resin for Models in Dentistry
by Scott Kirby, Igor Pesun, Anthony Nowakowski and Rodrigo França
Polymers 2024, 16(4), 549; https://doi.org/10.3390/polym16040549 - 18 Feb 2024
Viewed by 825
Abstract
The aim was to investigate the effects of different post-curing units on the chemical properties (degree of conversion) of 3D-printed resins for producing models in dentistry. The goal is to determine whether less-expensive post-curing units can be a viable alternative to the manufacturer’s [...] Read more.
The aim was to investigate the effects of different post-curing units on the chemical properties (degree of conversion) of 3D-printed resins for producing models in dentistry. The goal is to determine whether less-expensive post-curing units can be a viable alternative to the manufacturer’s recommended units. Forty-five samples were fabricated with an LCD printer (Phrozen Sonic Mini, Phrozen 3D, Hsinchu City, Taiwan) using MSLA Dental Modeling Resin (Apply Lab Work, Torrance, CA, USA). These samples were divided randomly into four different groups for post-curing using four distinct curing units: Phrozen Cure V2 (Phrozen 3D, Hsinchu City, Taiwan), a commercial acrylic nail UV LED curing unit (SUNUV, Shenzhen, China), a homemade curing unit created from a readily available UV LED light produced (Shenzhen, China), and the Triad® 2000™ tungsten halogen light source (Dentsply Sirona, York, PA, USA). The degree of conversion was measured with FTIR spectroscopy using a Nicolet 6700 FTIR Spectrometer (Thermo Fisher Scientific, Waltham, MA, USA). Phrozen Cure V2 had the highest overall mean degree of conversion (69.6% with a 45 min curing time). The Triad® 2000 VLC Curing Unit had the lowest mean degree of conversion value at the 15 min interval (66.2%) and the lowest mean degree of conversion at the 45 min interval with the homemade curing unit (68.2%). The type of light-curing unit did not yield statistically significant differences in the degree of conversion values. There was a statistically significant difference in the degree of conversion values between the 15 min and 45 min curing intervals. When comparing individual light-curing units, there was a statistically significant difference in the degree of conversion for the post-curing units between the 15 min and 45 min curing time (p = 0.029). Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Figure 1

12 pages, 3797 KiB  
Article
Projection Stereolithography 3D-Printed Bio-Polymer with Thermal Assistance
by Hao Pu, Yuhao Guo, Zhicheng Cheng, Zhuoxi Chen, Jing Xiong, Xiaoyang Zhu and Jigang Huang
Polymers 2023, 15(22), 4402; https://doi.org/10.3390/polym15224402 - 14 Nov 2023
Viewed by 1008
Abstract
A stereolithography process with thermal assistance is proposed in this work to address the tradeoff between the flowability and the high concentration of solute loadings at room temperature, through which the improved performance of polymers prepared using stereolithography 3D printing can be achieved. [...] Read more.
A stereolithography process with thermal assistance is proposed in this work to address the tradeoff between the flowability and the high concentration of solute loadings at room temperature, through which the improved performance of polymers prepared using stereolithography 3D printing can be achieved. For the experiment, polyethylene glycol diacrylate (PEGDA) with a high molecular weight of 4000 is adopted to improve the mechanical properties of 2-Hydroxyethyl methacrylate (HEMA). For the polymer of HEMA, the highest soluble concentration of PEGDA is about 20 wt% at 25 °C (room temperature) while the concentration could be raised up to 40 wt% as the temperature increases to 60 °C. The 3D printing tests showed that the objects could be easily fabricated with the HEMA polymer loaded with 40 wt% of PEGDA through the thermally assisted projection stereolithography technology. By adding the 40 wt% of PEGDA, the Young’s modulus has been enhanced by nearly 390% compared to the HEMA resin without solute, of which the Young’s modulus is 63.31 ± 2.72 MPa. The results of the cell proliferation test proved that the HEMA resin loaded with PEGDA led to a better biocompatibility compared to the HEMA resin without the loading of the PEGDA solute. All of the results demonstrate that the polymer loaded with high solute is feasible to be precisely 3D-printed using the projection stereolithography process with thermal assistance, and the improved mechanical properties are beneficial for biomedical applications. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Graphical abstract

12 pages, 4456 KiB  
Article
Engineering Toughness in a Brittle Vinyl Ester Resin Using Urethane Acrylate for Additive Manufacturing
by Mohanad Idrees, Heedong Yoon, Giuseppe R. Palmese and Nicolas J. Alvarez
Polymers 2023, 15(17), 3501; https://doi.org/10.3390/polym15173501 - 22 Aug 2023
Cited by 2 | Viewed by 953
Abstract
Thermosetting polymers tend to have a stiffness–toughness trade-off due to the opposing relationship of stiffness and toughness on crosslink density. We hypothesize that engineering the polymer network, e.g., by incorporating urethane oligomers, we can improve the toughness by introducing variations in crosslink density. [...] Read more.
Thermosetting polymers tend to have a stiffness–toughness trade-off due to the opposing relationship of stiffness and toughness on crosslink density. We hypothesize that engineering the polymer network, e.g., by incorporating urethane oligomers, we can improve the toughness by introducing variations in crosslink density. In this work, we show that a brittle methacrylated Bis-GMA resin (known as DA2) is toughened by adding a commercial urethane acrylate resin (known as Tenacious) in different proportions. The formulations are 3D printed using a vat photopolymerization technique, and their mechanical, thermal, and fracture properties are investigated. Our results show that a significant amount of Tenacious 60% w/w is required to produce parts with improved toughness. However, mechanical properties drop when the Tenacious amount is higher than 60% w/w. Overall, our results show that optimizing the amount of urethane acrylate can improve toughness without significantly sacrificing mechanical properties. In fact, the results show that synergistic effects in modulus and strength exist at specific blend concentrations. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Graphical abstract

13 pages, 10073 KiB  
Article
3D Embedded Printing of Complex Biological Structures with Supporting Bath of Pluronic F-127
by Tianzhou Hu, Zhengwei Cai, Ruixue Yin, Wenjun Zhang, Chunyan Bao, Linyong Zhu and Honbo Zhang
Polymers 2023, 15(17), 3493; https://doi.org/10.3390/polym15173493 - 22 Aug 2023
Viewed by 1316
Abstract
Biofabrication is crucial in contemporary tissue engineering. The primary challenge in biofabrication lies in achieving simultaneous replication of both external organ geometries and internal structures. Particularly for organs with high oxygen demand, the incorporation of a vascular network, which is usually intricate, is [...] Read more.
Biofabrication is crucial in contemporary tissue engineering. The primary challenge in biofabrication lies in achieving simultaneous replication of both external organ geometries and internal structures. Particularly for organs with high oxygen demand, the incorporation of a vascular network, which is usually intricate, is crucial to enhance tissue viability, which is still a difficulty in current biofabrication technology. In this study, we address this problem by introducing an innovative three-dimensional (3D) printing strategy using a thermo-reversible supporting bath which can be easily removed by decreasing the temperature. This technology is capable of printing hydrated materials with diverse crosslinked mechanisms, encompassing gelatin, hyaluronate, Pluronic F-127, and alginate. Furthermore, the technology can replicate the external geometry of native tissues and organs from computed tomography data. The work also demonstrates the capability to print lines around 10 μm with a nozzle with a diameter of 60 μm due to the extra force exerted by the supporting bath, by which the line size was largely reduced, and this technique can be used to fabricate intricate capillary networks. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Figure 1

19 pages, 7899 KiB  
Article
Fatigue Behavior of Rotary Friction Welding of Acrylonitrile Butadiene Styrene and Polycarbonate Dissimilar Materials
by Chil-Chyuan Kuo, Naruboyana Gurumurthy and Song-Hua Hunag
Polymers 2023, 15(16), 3424; https://doi.org/10.3390/polym15163424 - 16 Aug 2023
Viewed by 1105
Abstract
Understanding the fatigue behaviors of weld joints is significant in engineering practice. Rotary friction welding (RFW) can join the additively manufactured polymer components. Until now, no research has focused on the fatigue behavior of polymer components jointed via RFW. This study investigates the [...] Read more.
Understanding the fatigue behaviors of weld joints is significant in engineering practice. Rotary friction welding (RFW) can join the additively manufactured polymer components. Until now, no research has focused on the fatigue behavior of polymer components jointed via RFW. This study investigates the fatigue life of ABS/PC dissimilar components fabricated via RFW and proposes the fatigue mechanism based on the failure structure. This work uses five different cyclic loads and rotational speeds to investigate the fatigue life. The fatigue life of the RFW of ABS/PC dissimilar rods is better compared with the pure ABS and pure PC specimens due to weld and integrity microstructural changes resulting from the combination of ABS and PC materials. The number of cycles until the rupture of RFW of ABS/PC dissimilar components (y) can be determined by the cyclic load (x) according to the prediction equation of y = −838.25x2 − 2035.8x + 67,262. The fatigue life of the RFW of ABS/PC dissimilar components increase with the increased rotational speed. The number of cycles until rupture (y) can be determined by the different rotational speeds (x) according to the prediction equation of y = 315.21x2 + 2710.4x + 32,124. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Figure 1

14 pages, 4566 KiB  
Article
Effects of Infill Line Multiplier and Patterns on Mechanical Properties of Lightweight and Resilient Hollow Section Products Manufactured Using Fused Filament Fabrication
by Jibran Khaliq, Dharma Raj Gurrapu and Farah Elfakhri
Polymers 2023, 15(12), 2585; https://doi.org/10.3390/polym15122585 - 6 Jun 2023
Cited by 1 | Viewed by 2278
Abstract
Fused Filament Fabrication (FFF) is a popular additive manufacturing process for creating prototypes and end-use products. Infill patterns, which fill the interior of hollow FFF-printed objects, play a crucial role in determining the mechanical properties and structural integrity of hollow structures. This study [...] Read more.
Fused Filament Fabrication (FFF) is a popular additive manufacturing process for creating prototypes and end-use products. Infill patterns, which fill the interior of hollow FFF-printed objects, play a crucial role in determining the mechanical properties and structural integrity of hollow structures. This study investigates the effects of infill line multipliers and different infill patterns (hexagonal, grid, and triangle) on the mechanical properties of 3D printed hollow structures. Thermoplastic poly lactic acid (PLA) was used as the material for 3D-printed components. Infill densities of 25%, 50%, and 75% were chosen, along with a line multiplier of one. The results indicate that the hexagonal infill pattern consistently demonstrated the highest Ultimate Tensile Strength (UTS) of 1.86 MPa across all infill densities, out-performing the other two patterns. To maintain a sample weight below 10 g, a two-line multiplier was utilised for a 25% infill density sample. Remarkably, this combination exhibited a UTS value of 3.57 MPa, which is comparable to samples printed at 50% infill density, which were 3.83 MPa. This research highlights the importance of line multiplier in combination with infill density and infill pattens to ensuring the achievement of the desired mechanical properties in the final product. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Figure 1

17 pages, 2522 KiB  
Article
Novel Rhinological Application of Polylactic Acid—An In Vitro Study
by M. P. Gowrav, K. G. Siree, T. M. Amulya, M. B. Bharathi, Mohammed Ghazwani, Ali Alamri, Abdulatef Y. Alalkami, T. M. Pramod Kumar, Mohammed Muqtader Ahmed and Mohamed Rahamathulla
Polymers 2023, 15(11), 2521; https://doi.org/10.3390/polym15112521 - 30 May 2023
Cited by 1 | Viewed by 1033
Abstract
A novel approach to the treatment of sinusitis is the use of nasal stents. The stent is loaded with a corticosteroid, which prevents complications in the wound-healing process. The design is such that it will prevent the sinus from closing again. The stent [...] Read more.
A novel approach to the treatment of sinusitis is the use of nasal stents. The stent is loaded with a corticosteroid, which prevents complications in the wound-healing process. The design is such that it will prevent the sinus from closing again. The stent is 3D printed using a fused deposition modeling printer, which enhances the customization. The polymer utilized for the purpose of 3D printing is polylactic acid (PLA). The compatibility between the drugs and polymers is confirmed by FT-IR and DSC. The drug is loaded onto the polymer by soaking the stent in the drug’s solvent, known as the solvent casting method. Using this method, approximately 68% of drug loading is found to be achieved onto the PLA filaments, and a total of 72.8% of drug loading is obtained in terms of the 3D-printed stent. Drug loading is confirmed by the morphological characteristics of the stent by SEM, where the loaded drug is clearly visible as white specks on the surface of the stent. Drug release characterization is conducted by dissolution studies, which also confirm drug loading. The dissolution studies show that the release of drugs from the stent is constant and not erratic. Biodegradation studies were conducted after increasing the rate of degradation of PLA by soaking it in PBS for a predetermined duration of time. The mechanical properties of the stent, such as stress factor and maximum displacement, are discussed. The stent has a hairpin-like mechanism for opening inside the nasal cavity. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Figure 1

16 pages, 6040 KiB  
Article
Preparation and Modification of Porous Polyetheretherketone (PEEK) Cage Material Based on Fused Deposition Modeling (FDM)
by Hui Zhang, Mingde Duan, Shikun Qin and Zhuangya Zhang
Polymers 2022, 14(24), 5403; https://doi.org/10.3390/polym14245403 - 9 Dec 2022
Cited by 5 | Viewed by 1517
Abstract
To address the problems of the difficult processing and internal microstructure disorder of porous bearing cages, Polyetheretherketone (PEEK) porous self-lubricating bearing cage material was prepared based on a fused deposition molding (FDM) process, and the porous samples were heat-treated on this basis, the [...] Read more.
To address the problems of the difficult processing and internal microstructure disorder of porous bearing cages, Polyetheretherketone (PEEK) porous self-lubricating bearing cage material was prepared based on a fused deposition molding (FDM) process, and the porous samples were heat-treated on this basis, the research was carried out around the synergistic design of the material preparation, microstructure, and tribological properties. The results show that the pore size of the PEEK porous material prepared by the FDM process meets the requirements of the porous bearing cage; the samples with higher porosity also have higher oil content, and all the samples show high oil retention. Under dry friction conditions, the higher the porosity of the porous material, the larger the friction coefficient, and the friction coefficients of each sample after heat treatment show the same pattern; under starved lubrication conditions, the friction coefficient of the porous PEEK material decreased significantly compared to the compact PEEK material, showing a better self-lubrication effect, and the porous samples reached the best self-lubrication effect after heat treatment. The optimal process parameters were 60% mass fraction of NaCl, 40% mass fraction of PEEK, and the applied heat treatment process. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Figure 1

Review

Jump to: Research

19 pages, 4583 KiB  
Review
Recent Progress on Moisture Absorption Aging of Plant Fiber Reinforced Polymer Composites
by Quan Wang, Tuo Chen, Xiaodong Wang, Yue Zheng, Jiayu Zheng, Gaojie Song and Shuyi Liu
Polymers 2023, 15(20), 4121; https://doi.org/10.3390/polym15204121 - 17 Oct 2023
Cited by 7 | Viewed by 1600
Abstract
Plant fiber reinforced polymer matrix composites have attracted much attention in many industries due to their abundant resources, low cost, biodegradability, and lightweight properties. Compared with synthetic fibers, various plant fibers are easy to obtain and have different characteristics, making them a substitute [...] Read more.
Plant fiber reinforced polymer matrix composites have attracted much attention in many industries due to their abundant resources, low cost, biodegradability, and lightweight properties. Compared with synthetic fibers, various plant fibers are easy to obtain and have different characteristics, making them a substitute for synthetic fiber composite materials. However, the aging phenomenon of composite materials has been a key issue that hinders development. In natural environments, moisture absorption performance leads to serious degradation of the mechanical properties of composite materials, which delays the use of composite materials in humid environments. Therefore, the effects of moisture absorption performance of plant fiber composite materials on their mechanical properties have been summarized in this article, as well as various treatment methods to reduce the water absorption of composite materials. Full article
(This article belongs to the Special Issue 3D Printing Polymer: Processing and Fabrication)
Show Figures

Figure 1

Back to TopTop