scholarly journals 3D Printing of Solvent-Free Supramolecular Polymers

2021 ◽  
Vol 9 ◽  
Author(s):  
Harald Rupp ◽  
Wolfgang H. Binder

Additive manufacturing has significantly changed polymer science and technology by engineering complex material shapes and compositions. With the advent of dynamic properties in polymeric materials as a fundamental principle to achieve, e.g., self-healing properties, the use of supramolecular chemistry as a tool for molecular ordering has become important. By adjusting molecular nanoscopic (supramolecular) bonds in polymers, rheological properties, immanent for 3D printing, can be adjusted, resulting in shape persistence and improved printing. We here review recent progress in the 3D printing of supramolecular polymers, with a focus on fused deposition modelling (FDM) to overcome some of its limitations still being present up to date and open perspectives for their application.

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 305
Author(s):  
Linda Ritzen ◽  
Vincenzo Montano ◽  
Santiago J. Garcia

The use of self-healing (SH) polymers to make 3D-printed polymeric parts offers the potential to increase the quality of 3D-printed parts and to increase their durability and damage tolerance due to their (on-demand) dynamic nature. Nevertheless, 3D-printing of such dynamic polymers is not a straightforward process due to their polymer architecture and rheological complexity and the limited quantities produced at lab-scale. This limits the exploration of the full potential of self-healing polymers. In this paper, we present the complete process for fused deposition modelling of a room temperature self-healing polyurethane. Starting from the synthesis and polymer slab manufacturing, we processed the polymer into a continuous filament and 3D printed parts. For the characterization of the 3D printed parts, we used a compression cut test, which proved useful when limited amount of material is available. The test was able to quasi-quantitatively assess both bulk and 3D printed samples and their self-healing behavior. The mechanical and healing behavior of the 3D printed self-healing polyurethane was highly similar to that of the bulk SH polymer. This indicates that the self-healing property of the polymer was retained even after multiple processing steps and printing. Compared to a commercial 3D-printing thermoplastic polyurethane, the self-healing polymer displayed a smaller mechanical dependency on the printing conditions with the added value of healing cuts at room temperature.


2021 ◽  
Vol 58 (1) ◽  
pp. 176-185
Author(s):  
Georgiana Chisiu ◽  
Nicolae-Alexandru Stoica ◽  
Alina-Maria Stoica

Recently, 3D-printed polymeric materials have been successfully replacing the usual ones especially used in sliding systems like couplings. Among the polymeric materials, Acrylonitrile Butadiene Styrene (ABS) and Poly Lactic Acid (PLA) can be the competitive materials in such application after 3D-printing. In this study, 3D printing was used to produce samples from ABS and PLA via fused deposition modelling (FDM) technology. Then friction behavior of 3D-printed samples was investigated depending on printing orientation of the samples. Ultra High Molecular Polyethylene Weight (UHMWPE), as a well-known industrial polymer, was also used for comparing the friction behavior of 3D-printed ABS and PLA polymers. Friction tests were conducted using a pin-on-plate type tribometer according to ASTM G133 under different applied loads and sliding speeds at room temperature. It was found that printing orientation of all ABS and PLA samples has a considerable effect on their friction behavior. Transverse direction (T.D) of the 3D-printed samples shows higher coefficient of friction (COF) values than the longitudinal direction under all applied loads and sliding speeds. On the other hand, COF values obtained in both 3D-printed samples increase as the load and speed increase regardless of the printing direction. When both 3D-printed materials are compared, PLA samples exhibit lower COF values than ABS samples in both printing directions and under all loads and speeds. However, the UHMWPE sample produced with traditional method shows much lower COF values and stable change in friction behavior under all conditions compared to 3D-printed PLA and ABS samples.


2021 ◽  
Vol 11 (18) ◽  
pp. 8563
Author(s):  
Anesu Nyabadza ◽  
Mercedes Vázquez ◽  
Shirley Coyle ◽  
Brian Fitzpatrick ◽  
Dermot Brabazon

The use of flexible sensors has tripled over the last decade due to the increased demand in various fields including health monitoring, food packaging, electronic skins and soft robotics. Flexible sensors have the ability to be bent and stretched during use and can still maintain their electrical and mechanical properties. This gives them an advantage over rigid sensors that lose their sensitivity when subject to bending. Advancements in 3D printing have enabled the development of tailored flexible sensors. Various additive manufacturing methods are being used to develop these sensors including inkjet printing, aerosol jet printing, fused deposition modelling, direct ink writing, selective laser melting and others. Hydrogels have gained much attention in the literature due to their self-healing and shape transforming. Self-healing enables the sensor to recover from damages such as cracks and cuts incurred during use, and this enables the sensor to have a longer operating life and stability. Various polymers are used as substrates on which the sensing material is placed. Polymers including polydimethylsiloxane, Poly(N-isopropylacrylamide) and polyvinyl acetate are extensively used in flexible sensors. The most widely used nanomaterials in flexible sensors are carbon and silver due to their excellent electrical properties. This review gives an overview of various types of flexible sensors (including temperature, pressure and chemical sensors), paying particular attention to the application areas and the corresponding characteristics/properties of interest required for such. Current advances/trends in the field including 3D printing, novel nanomaterials and responsive polymers, and self-healable sensors and wearables will also be discussed in more detail.


2021 ◽  
pp. 1-14
Author(s):  
Ming Luo ◽  
Qinghao He ◽  
Hongjian Wang ◽  
Li Chang

Abstract In this paper, short carbon fiber reinforced nylon composites were fabricated using the fused deposition modelling (FDM) technology. In particular, different surface textures, namely convex squares and triangles, were created by using the printing method. It was found that the fiber reinforcements could effectively enhance the load-carry capacity of the printed polymeric materials. Moreover, the tribological performance of the composites can be further improved with the induced surface textures. Microscopic observations revealed that the surface textures are particularly beneficial for the wear reduction by collecting hard wear debris such as broken fibers and thus diminishing the three-body abrasive wear. The work has demonstrated that 3D printing technology has the great potential for developing new wear-resistant engineering materials by controlling and creating the desirable compositions and geometric structures/textures simultaneously.


2021 ◽  
Vol 5 (4) ◽  
pp. 78
Author(s):  
Beatrice Sabbatini ◽  
Alessandra Cambriani ◽  
Marco Cespi ◽  
Giovanni Filippo Palmieri ◽  
Diego Romano Perinelli ◽  
...  

Three-dimensional (3D) printing, or additive manufacturing, is a group of innovative technologies that are increasingly employed for the production of 3D objects in different fields, including pharmaceutics, engineering, agri-food and medicines. The most processed materials by 3D printing techniques (e.g., fused deposition modelling, FDM; selective laser sintering, SLS; stereolithography, SLA) are polymeric materials since they offer chemical resistance, are low cost and have easy processability. However, one main drawback of using these materials alone (e.g., polylactic acid, PLA) in the manufacturing process is related to the poor mechanical and tensile properties of the final product. To overcome these limitations, fillers can be added to the polymeric matrix during the manufacturing to act as reinforcing agents. These include inorganic or organic materials such as glass, carbon fibers, silicon, ceramic or metals. One emerging approach is the employment of natural polymers (polysaccharides and proteins) as reinforcing agents, which are extracted from plants or obtained from biomasses or agricultural/industrial wastes. The advantages of using these natural materials as fillers for 3D printing are related to their availability together with the possibility of producing printed specimens with a smaller environmental impact and higher biodegradability. Therefore, they represent a “green option” for 3D printing processing, and many studies have been published in the last year to evaluate their ability to improve the mechanical properties of 3D printed objects. The present review provides an overview of the recent literature regarding natural polymers as reinforcing agents for 3D printing.


2017 ◽  
Vol 107 (07-08) ◽  
pp. 520-523
Author(s):  
J. Prof. Bliedtner ◽  
M. Schilling

Das FDM (Fused Deposition Modeling)-Verfahren ist aufgrund der Vielzahl von industriellen und privaten Anwendungen gegenwärtig das erfolgreichste 3D-Druck-Verfahren. Ziel des Forschungs- und Entwicklungsprojektes „HP3D“ ist die effiziente Herstellung von großformatigen Bauteilen in einem echten 3D-Verfahren aus frei wählbaren thermoplastischen Kunststoffen. An die Umsetzung des Projekts wurde sehr komplex herangegangen, um zu garantieren, dass die mechanischen und dynamischen Eigenschaften der aufgebauten Teile den konzipierten Eigenschaften entsprechen.   The FDM process is currently the most successful 3D printing process due to the multitude of industrial and private applications. The aim of the research and development project HP3D is the efficient production of large-format components in a real 3D process made of freely selectable thermoplastics. The implementation of the project has been very complex in order to ensure that the mechanical and dynamic properties of the assembled parts correspond to the designed properties.


Pharmaceutics ◽  
2018 ◽  
Vol 10 (4) ◽  
pp. 203 ◽  
Author(s):  
Deck Tan ◽  
Mohammed Maniruzzaman ◽  
Ali Nokhodchi

Three-dimensional printing, also known as additive manufacturing, is a fabrication process whereby a 3D object is created layer-by-layer by depositing a feedstock material such as thermoplastic polymer. The 3D printing technology has been widely used for rapid prototyping and its interest as a fabrication method has grown significantly across many disciplines. The most common 3D printing technology is called the Fused Deposition Modelling (FDM) which utilises thermoplastic filaments as a starting material, then extrudes the material in sequential layers above its melting temperature to create a 3D object. These filaments can be fabricated using the Hot-Melt Extrusion (HME) technology. The advantage of using HME to manufacture polymer filaments for FDM printing is that a homogenous solid dispersion of two or more pharmaceutical excipients i.e., polymers can be made and a thermostable drug can even be introduced in the filament composition, which is otherwise impractical with any other techniques. By introducing HME techniques for 3D printing filament development can improve the bioavailability and solubility of drugs as well as sustain the drug release for a prolonged period of time. The latter is of particular interest when medical implants are considered via 3D printing. In recent years, there has been increasing interest in implementing a continuous manufacturing method on pharmaceutical products development and manufacture, in order to ensure high quality and efficacy with less batch-to-batch variations of the pharmaceutical products. The HME and FDM technology can be combined into one integrated continuous processing platform. This article reviews the working principle of Hot Melt Extrusion and Fused Deposition Modelling, and how these two technologies can be combined for the use of advanced pharmaceutical applications.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1524
Author(s):  
Sadikalmahdi Abdella ◽  
Souha H. Youssef ◽  
Franklin Afinjuomo ◽  
Yunmei Song ◽  
Paris Fouladian ◽  
...  

Three-dimensional (3D) printing is among the rapidly evolving technologies with applications in many sectors. The pharmaceutical industry is no exception, and the approval of the first 3D-printed tablet (Spiratam®) marked a revolution in the field. Several studies reported the fabrication of different dosage forms using a range of 3D printing techniques. Thermosensitive drugs compose a considerable segment of available medications in the market requiring strict temperature control during processing to ensure their efficacy and safety. Heating involved in some of the 3D printing technologies raises concerns regarding the feasibility of the techniques for printing thermolabile drugs. Studies reported that semi-solid extrusion (SSE) is the commonly used printing technique to fabricate thermosensitive drugs. Digital light processing (DLP), binder jetting (BJ), and stereolithography (SLA) can also be used for the fabrication of thermosensitive drugs as they do not involve heating elements. Nonetheless, degradation of some drugs by light source used in the techniques was reported. Interestingly, fused deposition modelling (FDM) coupled with filling techniques offered protection against thermal degradation. Concepts such as selection of low melting point polymers, adjustment of printing parameters, and coupling of more than one printing technique were exploited in printing thermosensitive drugs. This systematic review presents challenges, 3DP procedures, and future directions of 3D printing of thermo-sensitive formulations.


2021 ◽  
Author(s):  
Justin Carter ◽  
Kumar Vikram Singh ◽  
Fazeel Khan

Abstract The exploration of structures made of multiple materials is a growing area of research as additive manufacturing processing technologies such as fused deposition modeling (FDM) 3D printing allows for their fabrication. Such a technology allows for rapid prototyping of structural components with complex geometries or spatially distributed materials with different properties and functionalities. By selecting suitable spatial distribution of materials, the performance of structural components can be manipulated and enhanced as per different engineering application needs. For a low-cost design of structural prototypes using 3D printing processes, viscoelastic polymeric materials are often used, having inherent damping properties. In this research, vibration characteristics of thin plates which are axially graded with multiple polymeric materials are investigated. The goal is to understand the influence of material grading on the frequency and damping characteristics of graded plates. Although in literature, material grading along the thickness in designing composite laminates and their vibration characteristics are available, the performance of plates having axially graded viscoelastic polymers have not been investigated yet. Through systematic modeling and experimental plans, vibration characteristics of axially graded viscoelastic plates are presented here. In particular, the damping performance for different grading schemes is evaluated. It is anticipated that such analysis will allow accurate modeling and testing of design prototypes of structural components for future research, such as design and testing of graded panels for enhanced flutter characteristics.


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