Plastik og polymerer

Plasticitetsteori - tværsnit, bjælker, rammer og plader omhandler den grundlæggende plasticitets-teori og dens anvendelse på snitkraftoptagelse, plane plastiske bjælker og rammer og plastiske plader. Flydebetingelser og flydelov behandles for stift plastiske materialer. Diskontinuitetslinier (også kaldet glidelinier og flydelinier) gennemgås og ligeså det indre arbejde for diskontinuitetslinier i forskellige materialer, og der vises eksempler på deres anvendelse. Ekstremalprincipperne, det vil sige principperne for at finde nedre- og øvreværdier for bæreevner, forklares, og principperne anvendes til beregning af bæreevner for tværsnit med forskel-lige snitkræfter og kombinationer heraf. Plane, plastiske bjælker og rammer beregnes ligeledes med nedre- og øvreværdier, og det samme gøres for plader. For pladers vedkommende er der vednedreværdierne specielt lagt vægt på strimmel-metoden. Her opdeles plader i strimler - ofte krydsende strimler - og beregnes ved at se bort fra vridningsmomenter, hvorved beregningerne bliver analoge til bjælkeberegninger. Der er også angivet nedreværdimetoder for rektangulære plader, hvor vridningsmomenter er medregnet, og endelig er også øvreværdimetoden, der er identisk med den klassiske brudlinieteori, medtaget. Bogen er skrevet let tilgængelig og med mange eksempler og opgaver. I samme serie findes: Betonkonstruktioner efter DS 411 Stålkonstruktioner efter DS 412 Bygningsberegninger efter DS 409 og DS 410

Fibre hybridisation is a well-established methodology to enhance the failure strains of ¿bre reinforced composites. In a hybrid ¿bre composite, the matrix is reinforced by two or more types of ¿bres, with typically a large sti¿ness contrast. When exactly two types of ¿bres are used for reinforcement, the ¿bres with greater sti¿ness are conventionally called the low extension (LE) ¿bres, while those with greater compliance are called high extension (HE) ¿bres. Hybrid ¿bre composites are typically divided into three cate- gories. If layers of LE and HE ¿bres are stacked over one other, an interlayer or layer-by-layer con¿guration is obtained. If yarns of LE and HE ¿bres are co-woven to form a hybrid ¿bre composite, an intralayer or yarn-by-yarn con¿guration is obtained. Finally, if the LE and HE ¿bres are randomly mixed together, the intrayarn or ¿bre-by-¿bre con¿guration is obtained. From a manufacturing perspec- tive, it is most di¿cult to produce intrayarn composites, and easiest to produce interlayer composites. Hybridisation seeks to combine the advantages of both ¿bre types and alleviate some of the disadvantages. As an example, carbon ¿bre reinforced plastic (CFRP) composites exhibit good strength to weight ratio, but undergo brittle failure leading to low fracture toughness. On the other hand, glass ¿bre reinforced plastic (GFRP) composites exhibit ductile failure, but süer from a relatively higher density than CFRPs, resulting in a lower strength to weight ratio. By combining the carbon ¿bres and glass ¿bres at a microscopic level, intermediate properties can be achieved.

Applied Plastics Engineering Handbook: Processing, Sustainability, Materials, and Applications, Third Edition presents the fundamentals of plastics engineering, helping bring readers up-to-speed on new plastics, materials, processing and technology. This revised and expanded edition includes the latest developments in plastics, including areas such as biodegradable and biobased plastics, plastic waste, smart polymers, and 3D printing. Sections cover traditional plastics, elastomeric materials, bio-based materials, additives, colorants, fillers and plastics processing, including various key technologies, plastic recycling and waste. The final part of the book examines design and applications, with substantial updates made to reflect advancements in technology, regulations, and commercialization. Throughout the handbook, the focus is on engineering aspects of producing and using plastics. Properties of plastics are explained, along with techniques for testing, measuring, enhancing, and analyzing them. Practical introductions to both core topics and new developments make this work equally valuable for newly qualified plastics engineers seeking the practical rules-of-thumb they don't teach you in school and experienced practitioners evaluating new technologies or getting up-to-speed in a new field.

Flexible devices based on metal oxides: Achievements and prospects focuses on the integration of flexibility in electronic circuitry, sensing applications, energy conversion and storage, and environmental remediation. Flexibility in these applications offers great potential, especially in the areas of wearable sensors, solar cells, transistors, electronic skin, and human body monitoring. The book investigates flexible and wearable devices based on metal oxide nanostructures or thin films that are capable of bending, rolling, compression, and folding, all while maintaining their performance. Metal oxide nanomaterials display exceptional properties that include mechanical stress tolerance, high optical transparency, high carrier mobilities, wide band gap, high dielectric constant, and superconductivity, amongst others. In some cases, they are also earth abundant, environmentally benign, cost-effective, chemically stable, and compatible with low-cost wet-chemical synthesis routes. The focus of the book is on wearables manufactured using sustainable manufacturing methods and integrated into substrates that are flexible, inexpensive, recyclable, abundant, and lightweight, including polymer, textile, cellulose and cork substrates.

Sensory Polymers: From their Design to Practical Applications discusses recent developments in the field of sensory polymers and showcases the potential applications of these materials in food control and security, civil security, the biomedical field, environmental control and remediation, industrial control of chemicals, and more. Written by worldwide experts in the field, chapters provide in-depth knowledge on several different polymer sensors and their response to different stimuli, which makes this book a valuable resource for researchers and advanced students in polymer science, materials science, and chemistry, as well as those interested on sensing applications and chemical sensory systems, including industry R&D.

For 30 years, "Designing Plastic Parts for Assembly" has been the definitive guide for both seasoned part designers and novices to the field, facilitating cost-effective design decisions and ensuring that the plastic parts and products will stand up under use.The detailed yet simplified discussion of material selection, manufacturing techniques, and assembly procedures enables the reader to evaluate plastic materials and design plastic parts with confidence. Good joint design and implementation, the geometry and nature of the component parts, the types of load involved, and other fundamental information necessary for a successful outcome are all included. Throughout, the treatment is practice-oriented and focused on everyday problems and situations.The 10th edition includes an extensive revision of the chapter on welding techniques for plastics, including a new subchapter on hot gas welding. There are also many more minor updates, improvements, and corrections throughout, including numerous new color figures.

Covers the chemistry and physics of conjugated polymers, and how they can be designed and optimised for various electronic applications.

Biotechnological Production of Bioactive Phytochemicals of Medicinal Value: A Comprehensive Treatise covers a broad variety of methods for secondary metabolites production (both pharmaceuticals and cosmeceuticals), compiling state-of-the-art material about the current knowledge of in vitro production for a large number of bioactive phytochemicals. Plants are a source of bioactive compounds and specialty chemicals such as ginsenosides; paclitaxel, artemisinin, veregen and nutraceuticals. Biopharmaceuticals are important in human healthcare, and herbal actives are gaining importance all over the world. With natural resources dwindling, in vitro production of secondary compounds on a commercial scale is being more and more required. Besides providing an alternative technology to bypass difficulties, the plant tissue culture (used in a broad sense to include cell, tissue, and organ culture) offers many advantages. In vitro technology also facilitates novel means of conserving the genetic diversity of the germplasm of medicinal plants through cryopreservation, production of novel compounds through biotransformation, somatic hybridization, and selective gene transfer through recombinant DNA technology for enhancing metabolite production.

This easy-to-understand guide provides the necessary information to implement a scientific molding program. It is a hands-on reference for people on the molding floor, including those previously lacking theoretical background or formal education.The book covers how the injection molding machine prepares the plastic and understanding of plastic flow. The functions of the main machine components are explained and understanding of correct procedures and testing is developed. Each step of the process is clearly explained in a step-by-step manner, and simple examples of important calculations are provided. The practical approach is augmented by useful guides for troubleshooting and machine set-up. The 2nd edition has a new chapter covering the effects of making specific changes to the process, as well as a number of other improvements throughout. Bonus download included: Excel spreadsheet with tests for process and machine performance.Contents1. Injection Unit: Screw2. Injection Unit: Barrel3. Clamping Unit4. Ejectors/Controllers, Human Machine Interface (HMI)5. Machine Performance Testing6. Process Development Test7. Plastic Temperature8. Plastic Flow9. Plastic Pressure (Pack/Hold)10. Cooling11. Benchmarking the Injection Molding Process12. Process Troubleshooting13. What is Important on a Set-Up Sheet?14. Commonly Used Conversion Factors and Formulas15. Machine Set-Up16. Things That Hurt the Bottom Line of a Company17. Terms and Definitions

This book provides the background needed to understand not only the wide field of polymer processing, but also the emerging technologies associated with the plastics industry in the 21st century. It combines practical engineering concepts with modeling of realistic polymer processes. Divided into three sections, it provides the reader with a solid knowledge base in polymer materials, polymer processing, and modeling."Understanding Polymer Processing" is intended for the person who is entering the plastics manufacturing industry and as a textbook for students taking an introductory course in polymer processing. It also serves as a guide to the practicing engineer when choosing a process, determining important parameters and factors during the early stages of process design, and when optimizing such a process. Practical examples illustrating basic concepts are presented throughout the book.New in the third edition are chapters on data-driven modeling and physics-driven modeling, as well as new sections on manufacturing and dimentional analysis. In addition to a number of other smaller improvements and corrections throughout the book, bonus code downloads are also providided. Contents: Part I: Polymeric MaterialsThis section gives a general introduction to polymers, including mechanical behavior of polymers and melt rheology.Part II: Polymer ProcessingThe major polymer processes are introduced in this section, including extrusion, mixing, injection molding, thermoforming, blow molding, film blowing, and many others.Part III: ModelingThis last section delivers the tools to allow the engineer to solve back-of-the-envelope polymer processing models. It includes dimensional analysis and scaling, transport phenomena in polymer processing, and modeling polymer processes.

This text- and workbook provides a clearly written, comprehensive introduction to the major topics associated with plastics technology, from basic chemistry and processing methods to the problem of waste and the issue of recycling plastics. Guiding questions at the beginning of each lesson help the reader to work through the material in a targeted manner; success checks at the end of each lesson enable the reader to review what he/she has learned. It thus facilitates independent, self-paced learning, meeting the requirements of modern vocational training.

Micro and nano devices are an integral part of modern technology. To address the requirements of the state-of-the-art technology, topics are selected from both chip-based and flexible electronics. A wide range of carbon materials including graphene, carbon nanotube, glass-like carbon, porous carbon, carbon black, graphite, carbon nanofiber, laser-patterned carbon and heteroatom containing carbon are covered. This goal is to elucidate fundamental carbon material science along with compatible micro- and nanofabrication techniques. Real-life example of sensors, energy storage and generation devices, MEMS, NEMS and implantable bioelectronics enable visualization of the outcome of described processes. Students will also benefit from the attractive aspects of carbon science explained in simple terms. Hybridization, allotrope classification and microstructural models are presented with a whole new outlook. Discussions on less-studied, hypothetical and undiscovered carbon forms render the contents futuristic and highly appealing.

"Sustainable Packaging Materials" provides a concise introduction to the principles and practices of packaging sustainability. It addresses the important issues that concern packaging professionals, decision makers, managers, CTOs, legislators, researchers, and students, including the viability and future of recycling, bio- and oxo-degradable materials, and plastics alternatives such as paper, glass, and metal. Also covered are new regulations such as the extended producer responsibility (EPR) laws, their consequences as to what materials are likely to be banned, and whether microplastics should be a concern for packaging companies.Written by an experienced professor, educator, author, inventor, and entrepreneur, this book offers uniquely clear answers to these challenges, helping readers to identify packaging materials that are likely to be phased out to meet new regulations, and to find alternatives to benefit their research and businesses. They will also be equipped to follow guidelines on the use of various packaging materials to stay ahead of the demands of the industry, and to make informed choices about packaging materials by considering sustainability, performance, and cost. Furthermore, they will be informed of the emerging packaging trends in both academia and industry, and understand the issues associated with microplastic pollution, and the actions recommended to mitigate these challenges.