Hasil untuk "Polymers and polymer manufacture"

Yao Zhai, Yaoguang Ma, S. N. David et al.

Yunqing Zhu, C. Romain, Charlotte K. Williams

F. Krebs, S. Gevorgyan, Jan Alstrup

L. Tan, Wei Zhu, K. Zhou

Additive manufacturing (AM) is the process of printing 3D objects in a layer‐by‐layer manner. Polymers and their composites are some of the most widely used materials in modern industries and are of great interest in the field of AM due to their vast potential for various applications, especially in the medical, aerospace, and automotive industries. Many studies have been conducted to develop new polymer materials for AM techniques, which include vat photopolymerization, material jetting, powder bed fusion, material extrusion, binder jetting, and sheet lamination. Although several reviews on the development of polymer materials for AM have been published, most of them only focus on a specific application, process, or type of material. Therefore, this article serves to provide a comprehensive review on the progress in polymer material development for AM techniques. It begins with an introduction to different AM techniques, followed by highlighting the progress of their development. Material requirements, notable advances in newly developed materials and their potential applications are discussed in detail and summarized. This review concludes by identifying the major challenges currently encountered in using AM for polymer materials and providing insights into the valuable opportunities it presents, in hopes of spurring further development in this field.

H. Wu, W. Fahy, Steven Kim et al.

Abstract In recent years, there have been significant advances on materials development for additive manufacturing (AM) applications. However, the use of composites or nanocomposite materials for improved performance and multifunctionality are still limited. This review paper attempts to provide a comprehensive review of both commercially available materials as well as research activities related to recent progress on high-performance polymer nanocomposites that are being used in various AM techniques. Four AM techniques including Fused Filament Fabrication (FFF), Selective Laser Sintering (SLS), Multi Jet Fusion (MJF), and Stereolithography (SLA) are discussed. The development of printable polymer composites especially polymer nanocomposites is rapidly expanding the AM materials portfolio, which makes the production of multifunctional parts with complex structures possible.

N. M. Nurazzi, M. Asyraf, A. Khalina et al.

Even though natural fiber reinforced polymer composites (NFRPCs) have been widely used in automotive and building industries, there is still a room to promote them to high-level structural applications such as primary structural component specifically for bullet proof and ballistic applications. The promising performance of Kevlar fabrics and aramid had widely implemented in numerous ballistic and bullet proof applications including for bullet proof helmets, vest, and other armor parts provides an acceptable range of protection to soldiers. However, disposal of used Kevlar products would affect the disruption of the ecosystem and pollutes the environment. Replacing the current Kevlar fabric and aramid in the protective equipment with natural fibers with enhanced kinetic energy absorption and dissipation has been significant effort to upgrade the ballistic performance of the composite structure with green and renewable resources. The vast availability, low cost and ease of manufacturing of natural fibers have grasped the attention of researchers around the globe in order to study them in heavy armory equipment and high durable products. The possibility in enhancement of natural fiber’s mechanical properties has led the extension of research studies toward the application of NFRPCs for structural and ballistic applications. Hence, this article established a state-of-the-art review on the influence of utilizing various natural fibers as an alternative material to Kevlar fabric for armor structure system. The article also focuses on the effect of layering and sequencing of natural fiber fabric in the composites to advance the current armor structure system.

A. Kirillova, Taylor R Yeazel, Darya Asheghali et al.

Degradable polymers are used widely in tissue engineering and regenerative medicine. Maturing capabilities in additive manufacturing coupled with advances in orthogonal chemical functionalization methodologies have enabled a rapid evolution of defect-specific form factors and strategies for designing and creating bioactive scaffolds. However, these defect-specific scaffolds, especially when utilizing degradable polymers as the base material, present processing challenges that are distinct and unique from other classes of materials. The goal of this review is to provide a guide for the fabrication of biodegradable polymer-based scaffolds that includes the complete pathway starting from selecting materials, choosing the correct fabrication method, and considering the requirements for tissue specific applications of the scaffold.

M. Ramesh, L. Rajeshkumar, N. Srinivasan et al.

Abstract The current day target for material scientists and researchers is developing a wholesome material to satisfy the parameters such as durability, manufacturability, low cost, and lightweight. Extensive research studies are ongoing on the possible application of polymer matrix composites in engineering and technology, since these materials have an edge over conventional materials in terms of performance. Hybridization of reinforcements is considered to be a better option to enhance the efficiency and performance of composite materials. Accordingly, research studies focus on the surface treatment of natural fibers and the addition of nanofillers (natural or synthetic) by industry and academia to take the properties and application of composites to the next level. This review purely focuses on the influence of fillers on the properties of composites along with the probable application of filler-based polymer composites.

D. Fico, Daniela Rizzo, R. Casciaro et al.

Recently, Fused Filament Fabrication (FFF), one of the most encouraging additive manufacturing (AM) techniques, has fascinated great attention. Although FFF is growing into a manufacturing device with considerable technological and material innovations, there still is a challenge to convert FFF-printed prototypes into functional objects for industrial applications. Polymer components manufactured by FFF process possess, in fact, low and anisotropic mechanical properties, compared to the same parts, obtained by using traditional building methods. The poor mechanical properties of the FFF-printed objects could be attributed to the weak interlayer bond interface that develops during the layer deposition process and to the commercial thermoplastic materials used. In order to increase the final properties of the 3D printed models, several polymer-based composites and nanocomposites have been proposed for FFF process. However, even if the mechanical properties greatly increase, these materials are not all biodegradable. Consequently, their waste disposal represents an important issue that needs an urgent solution. Several scientific researchers have therefore moved towards the development of natural or recyclable materials for FFF techniques. This review details current progress on innovative green materials for FFF, referring to all kinds of possible industrial applications, and in particular to the field of Cultural Heritage.

M. Islam, Md. Hosne Mobarak, Md Israfil Hossain Rimon et al.

Shubham Sharma, P. Sudhakara, Jujhar Singh et al.

In the determination of the bioavailability of drugs administered orally, the drugs’ solubility and permeability play a crucial role. For absorption of drug molecules and production of a pharmacological response, solubility is an important parameter that defines the concentration of the drug in systemic circulation. It is a challenging task to improve the oral bioavailability of drugs that have poor water solubility. Most drug molecules are either poorly soluble or insoluble in aqueous environments. Polymer nanocomposites are combinations of two or more different materials that possess unique characteristics and are fused together with sufficient energy in such a manner that the resultant material will have the best properties of both materials. These polymeric materials (biodegradable and other naturally bioactive polymers) are comprised of nanosized particles in a composition of other materials. A systematic search was carried out on Web of Science and SCOPUS using different keywords, and 485 records were found. After the screening and eligibility process, 88 journal articles were found to be eligible, and hence selected to be reviewed and analyzed. Biocompatible and biodegradable materials have emerged in the manufacture of therapeutic and pharmacologic devices, such as impermanent implantation and 3D scaffolds for tissue regeneration and biomedical applications. Substantial effort has been made in the usage of bio-based polymers for potential pharmacologic and biomedical purposes, including targeted deliveries and drug carriers for regulated drug release. These implementations necessitate unique physicochemical and pharmacokinetic, microbiological, metabolic, and degradation characteristics of the materials in order to provide prolific therapeutic treatments. As a result, a broadly diverse spectrum of natural or artificially synthesized polymers capable of enzymatic hydrolysis, hydrolyzing, or enzyme decomposition are being explored for biomedical purposes. This summary examines the contemporary status of biodegradable naturally and synthetically derived polymers for biomedical fields, such as tissue engineering, regenerative medicine, bioengineering, targeted drug discovery and delivery, implantation, and wound repair and healing. This review presents an insight into a number of the commonly used tissue engineering applications, including drug delivery carrier systems, demonstrated in the recent findings. Due to the inherent remarkable properties of biodegradable and bioactive polymers, such as their antimicrobial, antitumor, anti-inflammatory, and anticancer activities, certain materials have gained significant interest in recent years. These systems are also actively being researched to improve therapeutic activity and mitigate adverse consequences. In this article, we also present the main drug delivery systems reported in the literature and the main methods available to impregnate the polymeric scaffolds with drugs, their properties, and their respective benefits for tissue engineering.

B. A. Venmathi Maran, Sivakamavalli Jeyachandran, Masanari Kimura

Polymeric nanofibers have emerged as a captivating medium for crafting structures with biomedical applications. Spinning methods have garnered substantial attention in the context of medical applications and neural tissue engineering, ultimately leading to the production of polymer fibers. In comparison with polymer microfibers, polymer nanofibers boasting nanometer-scale diameters offer significantly larger surface areas, facilitating enhanced surface functionalization. Consequently, polymer nanofiber mats are presently undergoing rigorous evaluation for a myriad of applications, including filters, scaffolds for tissue engineering, protective equipment, reinforcement in composite materials, and sensors. This review offers an exhaustive overview of the latest advancements in polymer nanofiber processing and characterization. Additionally, it engages in a discourse regarding research challenges, forthcoming developments in polymer nanofiber production, and diverse polymer types and its applications. Electrospinning has been used to convert a broad range of polymers into nanoparticle nanofibers, and it may be the only approach with significant potential for industrial manufacturing. The basics of these spinning techniques, highlighting the biomedical uses as well as nanostructured fibers for drug delivery, disease modeling, regenerative medicine, tissue engineering, and bio-sensing have been explored.

Dries Vaes, P. Puyvelde

Abstract Additive Manufacturing (AM), and more specifically Fused Filament Fabrication (FFF), allow the production of highly customized parts, provide enormous freedom-of-design and can lead to material savings due to the layer-by-layer material deposition that is inherent to this family of production processes. FFF utilizes both amorphous and semi-crystalline thermoplastic filaments as feedstock materials, offering a wider range of materials compared to some other polymer-based additive manufacturing techniques. However, the current trend where FFF, and AM in general, are changing from a technique for rapid prototyping to the production of fully functional parts designed for high-end applications creates the inevitable need to incorporate more engineering and high-performance thermoplastics, which are most often semi-crystalline polymers, into the material palette. Crystallization provides semi-crystalline polymers with some distinct features that set them apart from their amorphous counterparts, yet it also can present difficulties regarding their processing. Understanding of the behavior of semicrystalline polymers during FFF processing is thus a prerequisite to exploit their full potential. This review provides a broad overview of FFF processing of semicrystalline polymers. Particular focus lies on the impact of processing conditions and feedstock modifications, such as the incorporation of fillers or the formation of blends, on crystallinity as well as the microstructure of printed parts, the impact of microstructure on the mechanical performance, and general part quality. Furthermore, attention is given to some specific phenomena that can occur during printing of semi-crystalline feedstock filaments which have shown to strongly impact the printing process. Examples are self-nucleation in the case of insufficient heat transfer and melting, flow-induced crystallization due to high shear deformations upon extrusion, and the negative impact of crystallization on chain mobility which is relevant for the development of interlayer strength and on dimensional accuracy due to excessive shrinkage. Finally, this review is concluded with a critical outlook on perspectives for future research to address the current challenges that are still faced when employing semi-crystalline polymers as FFF feedstock.

Ermias Wubete Fenta, Berihun Abebaw Mebratie

Carbon nanotube (CNT)-polymer composites exhibit significant advancements in mechanical, electrical, and thermal properties, enabling numerous promising applications. This review delves into recent research on manufacturing methods, filament extrusion, additive manufacturing (AM), properties, and applications of CNT polymer composites. Factors like processing conditions, polymer types, and CNT concentrations determine the ultimate properties of the composite material. The dispersion of CNT within various manufacturing techniques, such as melt mixing, solution mixing, and in-situ polymerization, significantly impacts the properties of the composite material. These composite materials are extensively used in AM, particularly in 3D printing, where filament blends are extruded and printed to custom-shaped objects. The finding underscores the effect of CNT content on the properties of CNT-polymer composite material in different applications. However, gaps remain in optimizing manufacturing processes and AM techniques, essential for tailoring these composites to specific application needs. Future research should focus on developing cost-effective and scalable manufacturing methods to unlock the full potential of CNT-polymer composites in various industries.

F. Lupone, E. Padovano, Francesco Casamento et al.

Selective laser sintering (SLS) is a powder bed fusion technology that uses a laser source to melt selected regions of a polymer powder bed based on 3D model data. Components with complex geometry are then obtained using a layer-by-layer strategy. This additive manufacturing technology is a very complex process in which various multiphysical phenomena and different mechanisms occur and greatly influence both the quality and performance of printed parts. This review describes the physical phenomena involved in the SLS process such as powder spreading, the interaction between laser beam and powder bed, polymer melting, coalescence of fused powder and its densification, and polymer crystallization. Moreover, the main characterization approaches that can be useful to investigate the starting material properties are reported and discussed.

Matthieu Fischer, Carolina Blanco, Yvonne Spoerer et al.

Polyoxymethylene (POM) is a fast crystallizing polymer, whose structure is highly dependent on the processing conditions and is showing a broad range of mechanical properties. Three POM materials with different molecular weights were selected and a design of experiments (DoE) was performed varying melt temperature, mold temperature, and injection speed. In combination with increased viscosity at higher molecular weights, the flow resistance and shear stresses will also increase at a certain injection speed and geometric conditions. Thereby, the range of morphological differences depends not only on the process boundary conditions but also on the rheological conditions. This aspect is particularly relevant for micro-injection molded parts, as the acting cooling and shearing rates are much higher than in standard injection molding. A specially designed tensile rod with a radially symmetric cross section was utilized for the experiments, which offers advantages in terms of a symmetric flow and cooling behavior. The morphology was studied with thin sections from the center of the sample. Differential Scanning Calorimetry (DSC) was used to study the crystallinity of the samples and the mechanical properties were determined by a tensile test using an adopted optical extensometer. The mechanical properties of low molecular weight POM are only to a minor extent affected by the process variations. However, higher molecular weight POM is greatly affected in terms of its skin layer formation and improved mechanical properties favored by a low injection velocity.

Miryam Criado‐Gonzalez, A. Dominguez‐Alfaro, Naroa Lopez‐Larrea et al.

Conducting polymers (CPs) have been attracting great attention in the development of (bio)electronic devices. Most of the current devices are rigid two-dimensional systems and possess uncontrollable geometries and architectures that lead to poor mechanical properties presenting ion/electronic diffusion limitations. The goal of the article is to provide an overview about the additive manufacturing (AM) of conducting polymers, which is of paramount importance for the design of future wearable three-dimensional (3D) (bio)electronic devices. Among different 3D printing AM techniques, inkjet, extrusion, electrohydrodynamic, and light-based printing have been mainly used. This review article collects examples of 3D printing of conducting polymers such as poly(3,4-ethylene-dioxythiophene), polypyrrole, and polyaniline. It also shows examples of AM of these polymers combined with other polymers and/or conducting fillers such as carbon nanotubes, graphene, and silver nanowires. Afterward, the foremost applications of CPs processed by 3D printing techniques in the biomedical and energy fields, that is, wearable electronics, sensors, soft robotics for human motion, or health monitoring devices, among others, will be discussed.

Yun Zhang, Weiquan Feng, Wenkai Zhu et al.

Polymers with broad infrared emission and negligible solar absorption have been identified as promising radiative cooling materials to offer a sustainable and energy-saving venue. Although practical applications desire color for visual appearance, the current coloration strategies of polymer-based radiative cooling materials are constrained by material, cost, and scalability. Here, we demonstrate a universally applicable coloration strategy for polymer-based radiative cooling materials by nanoimprinting. By modulating light interference with periodic structures on polymer surfaces, specular colors can be induced while maintaining the hemispheric optical responses of radiative cooling polymers. The retrofit strategy is exemplified by four different polymer films with a minimum impact on optical responses compared to the pristine films. Polymer films feature low solar absorption of 1.7-3.7%, and daytime sub-ambient cooling is exemplified in the field test. The durability of radiative cooling and color are further validated by dynamic spectral analysis. Finally, the potential roll-to-roll manufacturing empowers a scalable, low-cost, and easy-retrofitting solution for colored radiative cooling films.

Codruta Victoria Tigmeanu, L. Ardelean, L. Rusu et al.

3D-printing application in dentistry not only enables the manufacture of patient-specific devices and tissue constructs, but also allows mass customization, as well as digital workflow, with predictable lower cost and rapid turnaround times. 4D printing also shows a good impact in dentistry, as it can produce dynamic and adaptable materials, which have proven effective in the oral environment, under its continuously changing thermal and humidity conditions. It is expected to further boost the research into producing a whole tooth, capable to harmoniously integrate with the surrounding periodontium, which represents the ultimate goal of tissue engineering in dentistry. Because of their high versatility associated with the wide variety of available materials, additive manufacturing in dentistry predominantly targets the production of polymeric constructs. The aim of this narrative review is to catch a glimpse of the current state-of-the-art of additive manufacturing in dentistry, and the future perspectives of this modern technology, focusing on the specific polymeric materials.

Usman Bashir, A. Hassan, Furqan Ahmed et al.

Abstract This paper proposes a numerical approach for predicting residual stresses induced during the additive manufacturing (AM) of polymer composites and their effect on the deformation behavior of the composites. A finite element (FE) model was developed on Abaqus/Standard for 3D printing of layered polymer composite using three polymers: HDPE, PVC, and ABS. The material properties of pure polymers and their blends were measured through tensile testing of injection-molded specimens. These properties were then used as input data in the FE model for the regions of pure polymers and their interfaces. An uncoupled thermo-mechanical analysis was performed, where a heat transfer analysis was realized first using elements birth (activation/deactivation) technique and a moving cylindrical volumetric heat source as a Fortran subroutine (DFLUX). With temperature input from thermal simulation, a mechanical analysis was carried out to deform the polymer composites along and across the print direction, i.e. under isostrain and isostress conditions, respectively. It was observed that the theoretical models existing in the literature underestimate the material properties as they do not consider the residual stresses developed during fabrication. The FE simulations predicted that the estimated material properties were 10 to 50% different from those calculated by the theoretical models, depending upon the residual stress level and the print direction.