Hasil untuk "Polymers and polymer manufacture"

S. Ligon, R. Liska, J. Stampfl et al.

Additive manufacturing (AM) alias 3D printing translates computer-aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. AM enables decentralized fabrication of customized objects on demand by exploiting digital information storage and retrieval via the Internet. The ongoing transition from rapid prototyping to rapid manufacturing prompts new challenges for mechanical engineers and materials scientists alike. Because polymers are by far the most utilized class of materials for AM, this Review focuses on polymer processing and the development of polymers and advanced polymer systems specifically for AM. AM techniques covered include vat photopolymerization (stereolithography), powder bed fusion (SLS), material and binder jetting (inkjet and aerosol 3D printing), sheet lamination (LOM), extrusion (FDM, 3D dispensing, 3D fiber deposition, and 3D plotting), and 3D bioprinting. The range of polymers used in AM encompasses thermoplastics, thermosets, elastomers, hydrogels, functional polymers, polymer blends, composites, and biological systems. Aspects of polymer design, additives, and processing parameters as they relate to enhancing build speed and improving accuracy, functionality, surface finish, stability, mechanical properties, and porosity are addressed. Selected applications demonstrate how polymer-based AM is being exploited in lightweight engineering, architecture, food processing, optics, energy technology, dentistry, drug delivery, and personalized medicine. Unparalleled by metals and ceramics, polymer-based AM plays a key role in the emerging AM of advanced multifunctional and multimaterial systems including living biological systems as well as life-like synthetic systems.

Abishek Kafle, E. Luis, R. Silwal et al.

Additive manufacturing (AM) or 3D printing is a digital manufacturing process and offers virtually limitless opportunities to develop structures/objects by tailoring material composition, processing conditions, and geometry technically at every point in an object. In this review, we present three different early adopted, however, widely used, polymer-based 3D printing processes; fused deposition modelling (FDM), selective laser sintering (SLS), and stereolithography (SLA) to create polymeric parts. The main aim of this review is to offer a comparative overview by correlating polymer material-process-properties for three different 3D printing techniques. Moreover, the advanced material-process requirements towards 4D printing via these print methods taking an example of magneto-active polymers is covered. Overall, this review highlights different aspects of these printing methods and serves as a guide to select a suitable print material and 3D print technique for the targeted polymeric material-based applications and also discusses the implementation practices towards 4D printing of polymer-based systems with a current state-of-the-art approach.

T. Rahim, Abdul Manaf Abdullah, H. Md. Akil

Abstract Fused deposition modeling (FDM) is one of the most widely used 3D printing techniques that utilizes polymers to create models, prototypes or even end products. Since 2009, the demand for FDM has been increasing at an incredible rate from one year to the next, and many experts believe that this technology has the potential to revolutionize manufacturing in many sectors. The main advantages of FDM technology are that the technique offers a simpler fabrication process and a more cost-effective method compared to other prominent 3D printing techniques, and yet, it is still capable of manufacturing complex geometries and cavities with reasonable dimensional accuracy. However, there are still some limitations and shortcomings that have been identified, especially pertaining to the lower mechanical properties exhibited in FDM parts compared to the parts produced by conventional methods such as injection and compression techniques. Therefore, this review article focused on recent developments and progress in the FDM technique in an attempt to improve the end performance of 3D-printed parts, along with current challenges and the future direction.

Geoffrey Prunet, Florent Pawula, G. Fleury et al.

Abstract There is a growing demand for flexible and wearable next-generation electronic devices that must be capable of bending and stretching under mechanical deformation. In this regard, energy harvesting technologies have immensely invested in organic and polymeric semiconducting materials due to their large-area synthesis, low cost, low toxicity, high flexibility, and tunable electronic properties. For example, electrically conductive π-conjugated polymers have been investigated in various thermoelectric technologies for producing stretchable, wearable, and light-weight thermoelectric devices that can harvest energy from a temperature gradient and produce electricity with no pollution or moving parts. In this review we initially provide a general overview of the thermoelectric principles and conductive polymer characteristics, followed by the recent progress in their application in flexible and wearable thermoelectric devices. We also evaluate new advances in manufacturing hybrids of π-conjugated polymers with other polymers, inorganic materials, or carbon nanostructures, and their applications in body energy harvesting and smart cooling.

Xiaobo Dong, David Lu, Tequila A. L. Harris et al.

(1) Different methods have been applied to fabricate polymeric membranes with non-solvent induced phase separation (NIPS) being one of the mostly widely used. In NIPS, a solvent or solvent blend is required to dissolve a polymer or polymer blend. N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF) and other petroleum-derived solvents are commonly used to dissolve some petroleum-based polymers. However, these components may have negative impacts on the environment and human health. Therefore, using greener and less toxic components is of great interest for increasing membrane fabrication sustainability. The chemical structure of membranes is not affected by the use of different solvents, polymers, or by the differences in fabrication scale. On the other hand, membrane pore structures and surface roughness can change due to differences in diffusion rates associated with different solvents/co-solvents diffusing into the non-solvent and with differences in evaporation time. (2) Therefore, in this review, solvents and polymers involved in the manufacturing process of membranes are proposed to be replaced by greener/less toxic alternatives. The methods and feasibility of scaling up green polymeric membrane manufacturing are also examined.

Daniel V. A. Ceretti, M. Edeleva, L. Cardon et al.

The assessment of the extent of degradation of polymer molecules during processing via conventional (e.g., extrusion and injection molding) and emerging (e.g., additive manufacturing; AM) techniques is important for both the final polymer material performance with respect to technical specifications and the material circularity. In this contribution, the most relevant (thermal, thermo-mechanical, thermal-oxidative, hydrolysis) degradation mechanisms of polymer materials during processing are discussed, addressing conventional extrusion-based manufacturing, including mechanical recycling, and AM. An overview is given of the most important experimental characterization techniques, and it is explained how these can be connected with modeling tools. Case studies are incorporated, dealing with polyesters, styrene-based materials, and polyolefins, as well as the typical AM polymers. Guidelines are formulated in view of a better molecular scale driven degradation control.

Linglan He, Junshi Zhang, Yue Ma et al.

To boost electrochemical performance, fluorine-containing constituents are often introduced into lithium metal batteries (LMBs) to achieve superior properties. However, the underlying mechanism governing positional effects of fluorinated species remains unclear. Herein, three typical gel polymer electrolytes: fluorinated solvent-dominated (FSD), fluorinated polymer-dominated (FPD), and dual-site fluorinated-dominated (DFD) are systematically fabricated to investigate the related influence. Ionic conductivity, XPS characterization and molecular dynamics confirm the contribution of fluorinated solvent to the formation of stable and anion-derived inorganic-rich solid electrolyte interphase (SEI) layer. Density functional theory (DFT) results demonstrate that fluorinated polymer exhibits enhanced interaction energies, leading to increased free ion concentration. While Consistent conclusions can be drawn from diffusion coefficient analysis and distribution of relaxation times (DRT) results. By synergistically combining the merits of fluorinated solvents and fluorinated polymer, an ionic conductivity of 1.19 mS cm−1 is obtained for DFD and a minor polarization of 12 mV is achieved over 8000 h at 1 mA cm−1 in Li//Li battery. After assembling with LiFePO4, capacity retentions of 91.3 % and 91.6 % are maintained after 200 cycles at 1C under 25 °C and 60 °C, showing exceptional cycling stability, respectively, particularly under elevated-temperature operating conditions.

Takuto Yagishita, Anne-Laure Fameau, Syuji Fujii et al.

IntroductionGas marbles have recently emerged as a new class of particle-stabilized gas–liquid systems. A gas marble consists of a single air bubble suspended in air and encapsulated by a thin liquid shell stabilized by solid particles, forming an air-in-liquid-in-air structure. Gas marbles can be generated using various edible particles, but their formation has so far been demonstrated almost exclusively in water, where only particles with intermediate wettability (moderately hydrophilic contact angles) lead to stable structures. Because liquid surface tension strongly influences the three-phase contact angle, expanding gas-marble formation beyond water requires understanding how the liquid phase governs gas marbles formation and stability.MethodsIn this work, we investigate the formation of gas marbles using cocoa particles and a wide range of edible liquids differing in surface tension and composition. We also systematically varied a model liquid phase from water/ethanol mixtures. Unlike previous studies that focused primarily on particle wettability in water-based systems, this work explicitly isolates and elucidates the role of the liquid phase in governing gas-marble formation.Results and discussionWe demonstrate that the three-phase contact angle can be tuned through liquid surface tension, enabling or inhibiting gas-marble formation. We show, for the first time, that stable cocoa-based gas marbles can be produced in a broad set of edible liquids, provided that the liquid surface tension remains sufficiently high (above 34 mN/m). These gas marbles exhibit notable robustness, including heat resistance and long-term stability. Overall, this study establishes clear criteria linking liquid surface tension, particle wettability, and gas-marble formation. These findings provide new physical insight into particle-stabilized gas–liquid interfaces beyond water systems and offer general formulation guidelines applicable across a wide range of edible and non-aqueous liquids.

Arulmozhivarman Joseph Chandran, S. Rangappa, Indran Suyambulingam et al.

The need for new sustainable engineering materials using polymer composites is evolving every day. Researchers are in a race to develop value‐added products from natural renewable sources and discarded waste materials. Studies indicate several hurdles while trying to provide ecologically friendly materials for product manufacturing over the years. Natural materials are more readily available, biodegradable, more affordable, have less processing health hazards, and are more environmentally friendly than synthetic materials. As the price of commercial polymers decreased, the incorporation of fillers became increasingly necessary for technical reasons.. The market for polymers can actually be expanded by appropriately combining fillers and polymers to produce a wide range of qualities in these two components. This review provides an overview on a variety of organic and inorganic fillers which were incorporated into the polymer composites and their influence on the physical, chemical, mechanical, thermal, and electrical properties of polymer composites by various characterization methods and their In fact, it is possible to achieve a wide range of qualities in these two components by appropriately combining polymers and fillers, which expands the market for which polymers may be employed.application scopes. This review aims to thoroughly examine and assess various polymer and filler combinations, with a particular emphasis on their potential suitability for a range of engineering and industrial applications. These encompass microelectronics, biomedical fields, flexible electronics, flame retardant uses, food packaging, automotive and aerospace sectors, as well as applications within the construction industry for structural and semi‐structural purposes.

A. Diniță, R. Rîpeanu, C. Ilincă et al.

Composites made from fiber-reinforced polymers (FRPs) are a crucial and highly adaptable category of materials widely utilized in numerous fields. Their flexibility and the range of criteria for classification enable the creation of tailored solutions to address distinct requirements in sectors such as civil engineering, aerospace, automotive, and marine, among others. The distinguishing characteristics of FRP composites include the type of reinforcing fiber used, the composition of the matrix material, the employed manufacturing process, the orientation of the fibers, and the specific end-use application. These classification variables offer engineers a versatile structure to determine and select the most appropriate materials and production techniques for their specific needs. Furthermore, the present study aims to reunite the criteria of classification for FRPs and specific manufacturing technologies of FRPs, such as conventional ones (matched die molding, contact molding), automated ones (filament winding, tape lay-up, and fiber placement), and advanced ones (electrospinning and additive manufacturing),with the chronological development of FRPs, insights on material characteristics, and comprehensive design guidelines based on their behavior in different environments of use.

Tahamina Nasrin, Farhad Pourkamali-Anaraki, Amy M. Peterson

Additive manufacturing (AM) is a revolutionary technology that enables production of intricate structures while minimizing material waste. However, its full potential has yet to be realized due to technical challenges such as the dependence of part quality on numerous process parameters, the vast number of design options, and the occurrence of defects. These complications may be magnified by the use of polymers and polymer composites due to their complex molecular structures, batch‐to‐batch variations, and changes in final part properties caused by small alterations in process settings and environmental conditions. Machine learning (ML), a branch of artificial intelligence, offers approaches to tackle these challenges and significantly reduce the experimental and computational time and expense. This review provides a comprehensive analysis of existing research on integrating ML techniques into polymer AM. It highlights the challenges involved in adopting ML in polymer AM, proposes potential solutions, and identifies areas for future research.

R. Lohmann, R. Letcher

Per- and polyfluoroalkyl substances (PFAS) are a diverse group of surface treatment chemicals falling under non-polymeric and polymeric categories. Polymeric PFAS are comprised of fluoropolymers, perfluoropolyethers and side-chain fluorinated polymers (SCFPs). Fluorinated polymers and polymeric substances have gained a significant market due to their chemical stability. To date, research and regulatory concern has primarily focused on the environmental occurrence and health effects of non-polymeric PFAS, particularly perfluoroalkyl acids and precursors. Industries consider most fluoropolymers as being "polymers of low concern", although there is already a considerable environmental burden and widespread contamination resulting from their production, manufacturing and use. For example, SCFPs are widely used, and known to release their perfluorinated side chains. Concerted action is needed to address the dearth of environment-associated information and understanding on polymeric PFAS.

میلاد قزلسفلو, مهدی سادات شجاعی, سهیلا قاسمی et al.

کیتوسان، نوعی پلیمر زیستی چندمنظوره مشتق‌ از کیتین است. این ماده به‌دلیل ویژگی‌های برجسته و کاربردهای متنوع آن در حوزه زیست‌پزشکی مورد توجه چشمگیری قرار گرفته است. این بررسی تجزیه و تحلیل جامعی از کاربردهای زیست‌پزشکی چندجانبه کیتوسان، شامل دارورسانی، مهندسی بافت، ترمیم زخم و پزشکی ترمیمی ارائه می‌دهد. ویژگی‌های منحصربه‌فرد کیتوسان از جمله زیست‌سازگاری، زیست‌تخریب‌پذیری، فعالیت ضدمیکروب و خواص زیست‌چسبی، آن را به نامزد ایده‌آلی برای کاربردهای مختلف زیست‌پزشکی تبدیل می‌کند. کیتوسان در سامانه‌های دارورسانی به‌عنوان حامل امیدوار کننده برای انتشار کنترل‌شده و هدفمند دارو، بهبود اثربخشی درمانی و کاهش آثار نامطلوب عمل می‌کند. ماهیت زیست‌سازگار و غیرسمی، آن را برای کپسول‌دار کردن طیف وسیعی از داروهای درمانی برای رهایش سامانمند یا موضعی مناسب می‌کند. افزون‌براین، نقش کیتوسان در مهندسی بافت و پزشکی ترمیمی بسیار مهم است. داربست‌های کیتوسان محیط مساعدی را برای رشد سلول، تمایز و بازسازی بافت فراهم کرده و امکان توسعه اندام‌های مصنوعی، کاشتینه‌ها و بافت‌های مهندسی‌شده فراهم می‌کند. خواص زیست‌چسبندگی کیتوسان، چسبندگی سلولی را تسهیل و ترمیم و بازسازی بافت را در کاربردهای ترمیم زخم تقویت می ­کند. همچنین، بررسی حاضر به اهمیت فزاینده کیتوسان در فناوری‌های خون­ایستی می‌پردازد، جایی که قابلیت آن در القای لخته شدن خون و پیشگیری از عفونت به بهبود مدیریت مراقبت از زخم کمک می‌کند. افزون­براین، نانوذرات و داربست‌های برپایة کیتوسان با امکان‌پذیر ساختن رویکردهای مناسب برای دارورسانی، ژن‌درمانی و بازسازی بافت، پژوهش­ های زیست‌پزشکی را متحول کرده است. درنتیجه، این بررسی بر نقش ضروری کیتوسان در پیشرفت فناوری‌های زیست­پزشکی و متحول کردن مداخلات درمانی تأکید می‌کند. خواص چندمنظوره کیتوسان، همراه با پژوهش ­ها و نوآوری‌های پیوسته در این حوزه، نویدبخش توسعه راه‌حل‌های نوین زیست‌پزشکی با آثار گسترده بر شیوه‌های مراقبت‌های بهداشتی و بهبود نتایج درمان بیماران است.

Pooyan Makvandi, S. Iftekhar, Fabio Pizzetti et al.

The inert nature of most commercial polymers and nanomaterials results in limitations of applications in various industrial fields. This can be solved by surface modifications to improve physicochemical and biological properties, such as adhesion, printability, wetting and biocompatibility. Polymer functionalization allows to graft specific moieties and conjugate molecules that improve material performances. In the last decades, several approaches have been designed in the industry and academia to graft functional groups on surfaces. Here, we review surface decoration of polymers and nanomaterials, with focus on major industrial applications in the medical field, textile industry, water treatment and food packaging. We discuss the advantages and challenges of polymer functionalization. More knowledge is needed on the biology behind cell–polymer interactions, nanosafety and manufacturing at the industrial scale.

Sharifah H. Alkandari, Bernardo Castro-Dominguez

The fabrication of membranes for gas separation presents challenges that hinder their deployment as a truly sustainable technology. This review systematically explores the evolution and advancements in materials and manufacturing methods of polymer-based membranes, with a keen emphasis on sustainability and efficiency. The review delineates a broad spectrum of manufacturing techniques, ranging from traditional methods to cutting-edge approaches such as layer-by-layer assembly, and green synthesis, highlighting their implications for environmental sustainability, performance enhancement, scalability, and economic viability. Key findings indicate a significant shift towards greener solvents, bio-based polymers and processes that reduce waste and costs. Critical analysis uncovers a growing focus on understanding the life cycle of membranes and developing strategies for end-of-life such as recycling and the use of biodegradable materials, underscoring the commitment of the community to minimizing environmental footprints.

Xuguang Xu, Wanglin Qiu, D. Wan et al.

ABSTRACT In material extrusion (MEX), it is challenging to accurately predict the steady and transient feeding forces at various polymer extrusion rates when printing island and thin-walled structures involving rapid start/stop or acceleration/deceleration, especially for semi-crystalline polymers. This research presents a non-isothermal viscoelastic Computational Fluid Dynamics model to investigate the steady and transient feeding forces, as well as the phase transition process and viscoelastic behaviour of polylactic acid (PLA), a semi-crystalline polymer, during the extrusion process. The study establishes a relationship between polymer flow and viscoelastic stress, demonstrating that the elastic effect during extrusion is more significant than the viscous effect, particularly at higher feeding rates. Furthermore, the study uncovers critical aspects of PLA melt flow behaviour during the MEX process, laying the foundation for future research and optimisation of MEX printing processes.

S. Sharafi, M. Santare, J. Gerdes et al.

Abstract Fracture toughness, is a critical aspect of a component’s strength and structural integrity. In additive manufacturing (AM) of polymers and polymer composites, the fracture toughness of the manufactured part is influenced by the bonding between the layers which is dependent on the material, geometric and processing parameters. Known factors that influence the bond strength and interfacial adhesion in 3D printed parts can be broadly divided into three main categories; 1) deposition related conditions (direction, nozzle size and geometry, temperature), 2) solidification related conditions (heat transfer, molecular movement, crystallinity and void formation) which also play a major role in defining properties and 3) composition and rheological behavior of the resins and the fiber microstructure (content, orientation and surface treatment). In this review, we identify factors that have been reported to influence interface bonding in 3D printed polymer and polymer composite parts. We discuss best practices, as recommended in the reported literature, to address fracture behavior and strategies to improve fracture toughness and structural integrity. Due to the layer-by-layer nature of 3D printed parts, which makes them orthotropic, most AM studies are mainly focused on application of Mode I and mixed mode loading to characterize interlaminar fracture toughness. Intralaminar and translaminar toughness behavior have mostly remained untouched or scarcely discussed in the AM literature. Our focus is to specifically address fracture toughness of 3D printed polymer composites made using the fused filament fabrication (FFF) additive manufacturing method. The material, process and geometric parameters used in FFF will impact the adhesion between layers and hence the fracture toughness and structural integrity. The review identifies the parameters that play key roles and discusses the mechanisms put forth by various researchers that influence the fracture toughness behavior under various modes of fracture. Important gaps in the literature are identified and the future outlook of AM using the FFF process is discussed.

M. Waqar, Naeem Mubarak, A. M. Khan et al.

Abstract Drug delivery via hydrogel is one of the most effective methods. Hydrogels have been described as polymeric water-swollen materials and retain water in distinctive three-dimensional complex. These are classified as pH sensitive hydrogels, temperature sensitive hydrogels, homo-polymer hydrogels, co-polymer hydrogels and Interpenetrating Network (IP-N) hydrogel. Hydrogels can be prepared via various techniques, including physical crosslinking, chemical crosslinking, free radical polymerization, photo-initiator’s and hydrogen bonding. Various polymers in manufacturing includes pectin, chitosan, cyclodextrin and carrageenan, etc. This review aims to describes hydrogels for drug delivery, classifications, preparation techniques, various polymers in hydrogel preparation and highlights novel applications of hydrogels in medicine. Graphical Abstract

Daniil R. Nosov, Elena I. Lozinskaya, Dmitrii Y. Antonov et al.

S. Nath, Sabrina Nilufar

Additive manufacturing is rapidly evolving and opening new possibilities for many industries. This article gives an overview of the current status of additive manufacturing with polymers and polymer composites. Various types of reinforcements in polymers and architectured cellular material printing including the auxetic metamaterials and the triply periodic minimal surface structures are discussed. Finally, applications, current challenges, and future directions are highlighted here.