Influence of Molecular Weight on the Mechanical Performance of a Thermoplastic Glassy Polyimide
Author: Lee M. Nicholson
Publisher:
Published: 1999
Total Pages: 36
ISBN-13:
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Author: Lee M. Nicholson
Publisher:
Published: 1999
Total Pages: 36
ISBN-13:
DOWNLOAD EBOOKAuthor: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Published: 2018-06
Total Pages: 34
ISBN-13: 9781720581222
DOWNLOAD EBOOKMechanical 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
Author: Kantesh Balani
Publisher: John Wiley & Sons
Published: 2015-01-23
Total Pages: 465
ISBN-13: 111895064X
DOWNLOAD EBOOKIdeal 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
Author:
Publisher:
Published: 2000
Total Pages: 182
ISBN-13:
DOWNLOAD EBOOKAuthor: Thomas S. Gates
Publisher:
Published: 2003
Total Pages: 24
ISBN-13:
DOWNLOAD EBOOKAuthor:
Publisher:
Published: 2001
Total Pages: 162
ISBN-13:
DOWNLOAD EBOOKAuthor: Minu Elizabeth Thomas
Publisher: Elsevier
Published: 2023-02-28
Total Pages: 628
ISBN-13: 0323909965
DOWNLOAD EBOOKComputational 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
Author:
Publisher:
Published: 2000
Total Pages: 900
ISBN-13:
DOWNLOAD EBOOKAuthor: William N. Sharpe, Jr.
Publisher: Springer Science & Business Media
Published: 2008-12-04
Total Pages: 1100
ISBN-13: 0387268839
DOWNLOAD EBOOKThe 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.
Author: G. M. Odegard
Publisher:
Published: 2002
Total Pages: 38
ISBN-13:
DOWNLOAD EBOOKIn this study, a technique is presented for developing constitutive models for polymer composite systems reinforced with single-walled carbon nanotubes (SWNT). Because the polymer molecules are on the same size scale as the nanotubes, the interaction at the polymer/nanotube interface is highly dependent on the local molecular structure and bonding. At these small length scales, the lattice structures of the nanotube and polymer chains cannot be considered continuous, and the bulk mechanical properties can no longer be determined through the traditional micromechanical approaches that are formulated by using continuum mechanics. It is proposed herein that the nanotube, the local polymer near the nanotube, and the nanotube/polymer interface can be modeled as an effective continuum fiber using an equivalent-continuum modeling method. The micromechanical analyses for the prediction of bulk mechanical properties of SWNT/polymer composites with various nanotube lengths, concentrations, and orientations. As an example, the proposed approach is used for the constitutive modeling of two SWNT/polyimide composite systems.