Relaxation of PET Orientation at Temperatures Below the Glass Transition - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Relaxation of PET Orientation at Temperatures Below the Glass Transition write by Brian M. Johnson. This book was released on 2013. Relaxation of PET Orientation at Temperatures Below the Glass Transition available in PDF, EPUB and Kindle. Polyethylene terephthalate (PET) is a semi-crystalline polyester widely used in industry as a material for food and beverage containers. Although the properties of amorphous PET make it a poor material to use for this application, its properties can be improved through molecular orientation, which is accomplished by deforming the polymer while it is heated above its glass transition temperature (Tg). Orientation is frozen-in by cooling PET below Tg, and can be unfrozen and rapidly relaxed by raising the temperature above this point. Although orientation often results in some degree of strain-induced crystallization (SIC), completely crystalline PET is not possible, and some orientation will exist in the amorphous phase. Additionally, PET molecules retain a small degree of mobility below Tg. A concern for oriented PET, then, is the potential of orientation relaxation when the material is exposed to sub-Tg temperatures of 30-40 °C for extended periods of time. The goal of this study was to determine the extent of relaxation that occurs when oriented PET is exposed to sub-Tg temperatures, as well as how its physical and mechanical properties change correspondingly. Samples of extruded PET sheet were oriented above Tg by stretching them biaxially to two different stretch ratios and rapidly quenched to room temperature. As-quenched birefringence, film dimensions, and mechanical properties of the oriented films were measured. The films were then stored in an air circulating oven at 40, 50, or 60 °C for up to a week. Every 24 hours a film was removed from the oven, and post-exposure birefringence, dimensions and density were measured. Mechanical properties were measured after 7 days of exposure. Measurements of film dimensions provided noteworthy results, with all films experiencing a small degree of shrinkage. Films exposed at 60 °C exhibited the most shrinkage, with a 0.5% decrease in dimensions after a week. Shrinkage followed a trend of exponential decay, and its full extent lessened as temperature was decreased. By fitting a model to the data, it was predicted that the amount of shrinkage after a week of exposure at 30 °C would be negligibly small. The results of birefringence did not follow any clear trends and require further investigation. Density of films following exposure did not show expected trends with time. An explanation proposed for this is the presence of physical aging, which is expected to increase density in unoriented amorphous regions and compete with the effects of relaxation on density. This possibility is supported by post-exposure mechanical properties, which exhibited changes consistent with physical aging.
Thermal Analysis of Polymers
Thermal Analysis of Polymers - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Thermal Analysis of Polymers write by Joseph D. Menczel. This book was released on 2014-07-09. Thermal Analysis of Polymers available in PDF, EPUB and Kindle. Presents a solid introduction to thermal analysis, methods, instrumentation, calibration, and application along with the necessary theoretical background. Useful to chemists, physicists, materials scientists, and engineers who are new to thermal analysis techniques, and to existing users of thermal analysis who wish expand their experience to new techniques and applications Topics covered include Differential Scanning Calorimetry and Differential Thermal Analysis (DSC/DTA), Thermogravimetry, Thermomechanical Analysis and Dilatometry, Dynamic Mechanical Analysis, Micro-Thermal Analysis, Hot Stage Microscopy, and Instrumentation. Written by experts in the various areas of thermal analysis Relevant and detailed experiments and examples follow each chapter.
SPE/ANTEC 2000 Proceedings
SPE/ANTEC 2000 Proceedings - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook SPE/ANTEC 2000 Proceedings write by Spe. This book was released on 2000-05-05. SPE/ANTEC 2000 Proceedings available in PDF, EPUB and Kindle. Volume 2 of the conference proceedings of the SPE/Antac on 'Materials', held on the 711 May 2000 in Orlando, Florida, USA.
Applied Plastics Engineering Handbook
Applied Plastics Engineering Handbook - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Applied Plastics Engineering Handbook write by Myer Kutz. This book was released on 2023-11-24. Applied Plastics Engineering Handbook available in PDF, EPUB and Kindle. 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. Offers an ideal reference for new engineers, experienced practitioners and researchers entering a new field or evaluating a new technology Provides an authoritative source of practical advice, presenting guidance that will lead to cost savings and process improvements Includes the latest technology, covering 3D printing, smart polymers and thorough coverage of biobased and biodegradable plastics
Electrical and Electronic Properties of Materials
Electrical and Electronic Properties of Materials - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Electrical and Electronic Properties of Materials write by Md. Kawsar Alam. This book was released on 2019-01-16. Electrical and Electronic Properties of Materials available in PDF, EPUB and Kindle. Materials properties, whether microscopic or macroscopic, are of immense interest to the materials scientists, physicists, chemists as well as to engineers. Investigation of such properties, theoretically and experimentally, has been one of the fundamental research directions for many years that has also resulted in the discovery of many novel materials. It is also equally important to correctly model and measure these materials properties. Keeping such interests of research communities in mind, this book has been written on the properties of polyesters, varistor ceramics, and powdered porous compacts and also covers some measurement and parameter extraction methods for dielectric materials. Four contributed chapters and an introductory chapter from the editor explain each class of materials with practical examples.
