Download or read book Influence of Molecular Weight on the Mechanical Performance of a Thermoplastic Glassy Polyimide written by Lee M. Nicholson and published by . This book was released on 1999 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Molecular Weight on the Mechanical Performance of a Thermoplastic Glassy Polyimide written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanical Testing of an advanced thermoplastic polyimide (LaRC-TM-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The physical characterization, elastic properties and notched tensile strength were all determined as a function of molecular weight and test temperature. It was shown that notched tensile strength is a strong function of both temperature and molecular weight, whereas stiffness is only a strong function of temperature. A critical molecular weight (Mc) was observed to occur at a weight-average molecular weight (Mw) of approx. 22000 g/mol below which, the notched tensile strength decreases rapidly. This critical molecular weight transition is temperature-independent. Furthermore, inelastic analysis showed that low molecular weight materials tended to fail in a brittle manner, whereas high molecular weight materials exhibited ductile failure. The microstructural images supported these findings.Nicholson, Lee M. and Whitley, Karen S. and Gates, Thomas S. and Hinkley, Jeffrey A.Langley Research CenterMOLECULAR WEIGHT; MECHANICAL PROPERTIES; POLYIMIDES; ELASTIC PROPERTIES; THERMOPLASTICITY; TENSILE STRENGTH; DUCTILE-BRITTLE TRANSITION; TEMPERATURE DEPENDENCE; FRACTOGRAPHY; GLASS TRANSITION TEMPERATURE; STRESS-STRAIN DIAGRAMS; MODULUS OF ELASTICITY; MICROSTRUCTURE; POLYMER MATRIX COMPOSITES; NOTCHES; TENSILE TESTS
Download or read book The Combined Influence of Molecular Weight and Temperature on the Aging and Viscoelastic Response of a Glassy Thermoplastic Polyimide written by Lee M. Nicholson and published by . This book was released on 2000 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of molecular weight on the viscoelastic performance of an advanced polymer (LaRC-SI) was investigated through the use of creep compliance tests. Testing consisted of short-term isothermal creep and recovery with the creep segments performed under constant load. The tests were conducted at three temperatures below the glass transition temperature of five materials of different molecular weight. Through the use of time-aging-time superposition procedures, the material constants, material master curves and aging-related parameters were evaluated at each temperature for a given molecular weight. The time-temperature superposition technique helped to describe the effect of temperature on the timescale of the viscoelastic response of each molecular weight. It was shown that the low molecular weight materials have higher creep compliance and creep rate, and are more sensitive to temperature than the high molecular weight materials. Furthermore, a critical molecular weight transition was observed to occur at a weight-average molecular weight of ~2500 g/mol below which, the temperature sensitivity of the time-temperature superposition shift factor increases rapidly. The short-term creep compliance data were used in association with Struik's effective time theory to predict the long-term creep compliance behavior for the different molecular weights. At long timescales, physical aging serves to significantly decrease the creep compliance and creep rate of all the materials tested.
Download or read book Biosurfaces written by Kantesh Balani and published by John Wiley & Sons. This book was released on 2015-01-23 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ideal as a graduate textbook, this title is aimed at helping design effective biomaterials, taking into account the complex interactions that occur at the interface when a synthetic material is inserted into a living system. Surface reactivity, biochemistry, substrates, cleaning, preparation, and coatings are presented, with numerous case studies and applications throughout. Highlights include: Starts with concepts and works up to real-life applications such as implantable devices, medical devices, prosthetics, and drug delivery technology Addresses surface reactivity, requirements for surface coating, cleaning and preparation techniques, and characterization Discusses the biological response to coatings Addresses biomaterial-tissue interaction Incorporates nanomechanical properties and processing strategies
Download or read book The Role of Molecular Weight and Temperature on the Elastic and Viscoelastic Properties of a Glassy Thermoplastic Polyimide written by Lee M. Nicholson and published by . This book was released on 2001 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanical testing of the elastic and viscoelastic response of an advanced thermoplastic polyimide (LaRC-SI) with known variations in molecular weight was performed over a range of temperatures below the glass transition temperature. The notched tensile strenght was shown to be a strong function of both molecular weight and temperature, whereas stiffness was only a strong function of temperature. A critical molecular weight was observed to occur at a weight-average molecular weight of ~22,000 g/mol below which, the notched tensile strength decreases rapidly. This critical molecular weight transition is temperature-independent. Low molecular weight materials tended to fail in a brittle manner, whereas high molecular weight materials exhibited ductile failure.
Download or read book NASA Langley Scientific and Technical Information Output 1999 written by and published by . This book was released on 2000 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Materials Modeling and Simulation of Nanostructured Materials and Systems written by Thomas S. Gates and published by . This book was released on 2003 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In Silico Approaches to Macromolecular Chemistry written by Minu Elizabeth Thomas and published by Elsevier. This book was released on 2023-02-28 with total page 628 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational approaches offer researchers unique insights into the structure, characteristics, and properties of macromolecules. However, with applications across a broad range of areas, various methods have been developed for exploring macromolecules in in silico; therefore, it can be difficult for researchers to select the most appropriate method for their specific needs. Covering both biopolymers and synthetic polymers, In-Silico Approaches to Macromolecular Chemistry familiarizes readers with the theoretical tools and software appropriate for such studies. In addition to providing essential background knowledge on both computational tools and macromolecules, the book presents in-depth studies of in silico macromolecule chemistry, discusses and compares these with experimental studies, and highlights the future potential for such approaches. Written by specialists in their respective fields, this book helps students, researchers, and industry professionals gain a clear overview of the field, and furnishes them with the knowledge needed to understand and select the most appropriate tools for conducting and analyzing computational studies. - Highlights in silico studies of both bio and synthetic macromolecules in one book - Supports both learners and experts though a combination of detailed guidance and perspectives on the future potential for in silico approaches to macromolecules - Familiarizes readers with theoretical tools and software helping them select the best approach for their specific needs
Download or read book NASA Langley Scientific and Technical Information Output 2000 written by and published by . This book was released on 2001 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 2000 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Springer Handbook of Experimental Solid Mechanics written by William N. Sharpe, Jr. and published by Springer Science & Business Media. This book was released on 2008-12-04 with total page 1100 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Springer Handbook of Experimental Solid Mechanics documents both the traditional techniques as well as the new methods for experimental studies of materials, components, and structures. The emergence of new materials and new disciplines, together with the escalating use of on- and off-line computers for rapid data processing and the combined use of experimental and numerical techniques have greatly expanded the capabilities of experimental mechanics. New exciting topics are included on biological materials, MEMS and NEMS, nanoindentation, digital photomechanics, photoacoustic characterization, and atomic force microscopy in experimental solid mechanics. Presenting complete instructions to various areas of experimental solid mechanics, guidance to detailed expositions in important references, and a description of state-of-the-art applications in important technical areas, this thoroughly revised and updated edition is an excellent reference to a widespread academic, industrial, and professional engineering audience.
Download or read book The Effect of Radiation on Properties of Polymers written by Laurence W. McKeen and published by William Andrew. This book was released on 2020-08-20 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Effect of Radiation on Properties of Polymers examines the effects of radiation on plastics and elastomers. Polymers are required in products or parts for a range of cutting-edge applications that are exposed to radiation, in areas such as space, medicine, and radiation processing. This book focuses on the effects of radiation exposure within that environment, providing in-depth data coverage organized by category of polymer. Aspects such as radiation impact on mechanical and thermal properties, including glass transition and heat deflection temperatures, are described, demonstrating how changes in these properties affect the performance of plastic or elastomer parts. The effect of radiation on electrical properties is also included. Supporting introductory chapters explain the key concepts of radiation, including the physical, mechanical, and thermal properties of plastics and elastomers. This is a vital resource for plastics engineers, product designers, and R&D professionals, working on products or parts for radioactive environments, as well as engineers and scientists in the medical, nuclear, and radiation processing industries. The book also supports researchers and scientists in plastics engineering, polymer processing and properties, polymer and coatings chemistry, materials science, and radiation. - Brings together highly valuable data on the effect of radiation on the properties of polymers and elastomers - Enables the reader to compare properties and to select the best possible materials for specific applications - Supported by detailed explanations and analysis, ensuring that the reader understands how to interpret and utilize the data
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis and Performance of Fiber Composites written by Bhagwan D. Agarwal and published by John Wiley & Sons. This book was released on 2017-09-26 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Updated and expanded coverage of the latest trends and developments in fiber composite materials, processes, and applications Analysis and Performance of Fiber Composites, Fourth Edition features updated and expanded coverage of all technical aspects of fiber composites, including the latest trends and developments in materials, manufacturing processes, and materials applications, as well as the latest experimental characterization methods. Fiber reinforced composite materials have become a fundamental part of modern product manufacturing. Routinely used in such high-tech fields as electronics, automobiles, aircraft, and space vehicles, they are also essential to everyday staples of modern life, such as containers, piping, and appliances. Little wonder, when one considers their ease of fabrication, outstanding mechanical properties, design versatility, light weight, corrosion and impact resistance, and excellent fatigue strength. This Fourth Edition of the classic referencethe standard text for composite materials courses, worldwideoffers an unrivalled review of such an important class of engineering materials. Still the most comprehensive, up-to-date treatment of the mechanics, materials, performance, analysis, fabrication, and characterization of fiber composite materials available, Analysis and Performance of Fiber Composites, Fourth Edition features: Expanded coverage of materials and manufacturing, with additional information on materials, processes, and material applications Updated and expanded information on experimental characterization methodsincluding many industry specific tests Discussions of damage identification techniques using nondestructive evaluation (NDE) Coverage of the influence of moisture on performance of polymer matrix composites, stress corrosion of glass fibers and glass reinforced plastics, and damage due to low-velocity impact New end-of-chapter problems and exercises with solutions found on an accompanying website Computer analysis of laminates No other reference provides such exhaustive coverage of fiber composites with such clarity and depth. Analysis and Performance of Fiber Composites, Fourth Edition is, without a doubt, an indispensable resource for practicing engineers, as well as students of mechanics, mechanical engineering, and aerospace engineering. Visit the Companion Website at: https://www.wiley.com/WileyCDA/Section/id-830336.html
Download or read book Fatigue in Composites written by Bryan Harris and published by Woodhead Publishing. This book was released on 2003-10-31 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: A survey of work on the fatigue behavior of composites dealing with the problems met with by materials scientists and designers in aerospace, automotive, marine, and structural engineering. Including a historical review, standards, micromechanical aspects, life-prediction methods for constant stress and variable stress, and fatigue in practical situations.
Download or read book Material Selection for Thermoplastic Parts written by Michel Biron and published by William Andrew. This book was released on 2015-09-02 with total page 712 pages. Available in PDF, EPUB and Kindle. Book excerpt: As new applications are developed and plastics replace traditional materials in a widening spectrum of existing applications, the potential personal injury, property damage, financial and legal consequences of failure can be high. However, nearly half of plastics failure can be traced back to the original specification and selection of the material. This book gives engineers the data they need to make an informed decision about the materials they use in their products, imparting a thorough knowledge of the advantages and disadvantages of the various materials to choose from. The data also suggests other candidate materials which the reader may not have originally considered. More than 30,000 thermoplastics grades are grouped into circa. 300 subfamilies, within which over 20 properties are assessed. The abundance or scarcity of a material and its cost are also often important deciding factors. In this book, an economical overview of the plastics industry helps clarify the actual consumption and costs of thermoplastics including bioplastic, and the relationship of cost vs. performance is also examined for each thermoplastic subfamily. Immediate and long-term common properties are reviewed, including mechanical behavior, impact, thermal properties, and many more. Environmental considerations are also covered, including ease of recycling and sustainability. - Helps engineers to implement a systematic approach to material selection in their work - Includes more than 300 subfamilies of thermoplastic, and a wide range of properties including chemical resistance, thermal degradation, creep and UV resistance - Evaluates cost/performance relations and environmental considerations
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1994 with total page 1036 pages. Available in PDF, EPUB and Kindle. Book excerpt:
