Enthalpy Relaxation Processes Near the Glass Transition Temperature of Poly (ethylene Terephthalate) - 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 Enthalpy Relaxation Processes Near the Glass Transition Temperature of Poly (ethylene Terephthalate) write by Trishna Ray-Chaudhuri. This book was released on 1988. Enthalpy Relaxation Processes Near the Glass Transition Temperature of Poly (ethylene Terephthalate) available in PDF, EPUB and Kindle.
Temperature and Rate Dependent Finite Strain Behavior of Poly(ethylene Terephthalate) and Poly(ethylene Terephthalate)-glycol Above the Glass Transition Temperature
Temperature and Rate Dependent Finite Strain Behavior of Poly(ethylene Terephthalate) and Poly(ethylene Terephthalate)-glycol Above the Glass Transition Temperature - 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 Temperature and Rate Dependent Finite Strain Behavior of Poly(ethylene Terephthalate) and Poly(ethylene Terephthalate)-glycol Above the Glass Transition Temperature write by Rebecca Brown Dupaix. This book was released on 2003. Temperature and Rate Dependent Finite Strain Behavior of Poly(ethylene Terephthalate) and Poly(ethylene Terephthalate)-glycol Above the Glass Transition Temperature available in PDF, EPUB and Kindle. (Cont.) The model predicts the temperature and rate dependence of many stress-strain features of PET and PETG very well, including the initial modulus, flow stress, initial hardening modulus, and dramatic strain hardening. The modeling results indicate that the large strain hardening behavior of both materials can only be captured by including a critical orientation parameter to halt the molecular relaxation process once the network achieves a specific level of molecular orientation. This suggests that much of the strain hardening in PET is due to molecular orientation and not to strain-induced crystallization. An example blow molding process is simulated to demonstrate the industrial applicability of the proposed model.
The Glass Transition
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 The Glass Transition write by E. Donth. This book was released on 2013-04-17. The Glass Transition available in PDF, EPUB and Kindle. Describes and interrelates the following processes: cooperative alpha processes in a cold liquid, structural relaxation in the glass near Tg, the Johari-Goldstein beta process, the Williams-Götze process in a warm liquid, fast nonactivated cage rattling and boson peak, and ultraslow Fischer modes.
Advances in Crystallization Processes
Advances in Crystallization Processes - 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 Advances in Crystallization Processes write by Yitzhak Mastai. This book was released on 2012-04-27. Advances in Crystallization Processes available in PDF, EPUB and Kindle. Crystallization is used at some stage in nearly all process industries as a method of production, purification or recovery of solid materials. In recent years, a number of new applications have also come to rely on crystallization processes such as the crystallization of nano and amorphous materials. The articles for this book have been contributed by the most respected researchers in this area and cover the frontier areas of research and developments in crystallization processes. Divided into five parts this book provides the latest research developments in many aspects of crystallization including: chiral crystallization, crystallization of nanomaterials and the crystallization of amorphous and glassy materials. This book is of interest to both fundamental research and also to practicing scientists and will prove invaluable to all chemical engineers and industrial chemists in the process industries as well as crystallization workers and students in industry and academia.
Relaxation of PET Orientation at Temperatures Below the Glass Transition
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.
