Crystallization Modalities in Polymer Melt Processing: Fundamental Aspects of Structure Formation

ISBN-13: 9783211876268 / Angielski / Twarda / 2009 / 240 str.

Hermann Janeschitz-Kriegl

Opis

Structure formation in crystallizing polymers, as occurring during processing, has not been treated so far in a coherent form. This fact explains, why this monograph is written as the ?rst book devoted to this subject. A quarter of a century ago the underdevelopment of this subject was obvious. Trial and error dominated. In fact, other apposite subjects as polymer melt rheology or heat transfer, had reached high levels. A great number of books has been devoted to them. Mold ?lling of amorphous polymers and the solidi?cation of these polymers by vitri?cation can nowadays be simulated numerically with a high degree of accuracy. In the solidi?ed sample even residual stresses and corresponding birefringence effects can accurately be 1 calculated . However, semicrystalline polymers, which form the majority of industrial po- mers, have been excluded from these considerations for good reasons. In fact, great uncertainties existed about the formation of quality determining crystalline str- tures. In particular, polyole?ns suffered from this shortcoming. In 1983 this fact instigated the polymer research group at the Johannes Kepler University in Linz to start with pertinent activities. The urgency of this kind of studies becomes evident, if advantages and hitches of these polymers are considered. 1. Versatility of processing: Injection molding into a great variety of shapes and sizes, from thin walled beakers to garden chairs, not to forget pipe and pro?le extrusion, cable coating, ?ber spinning, ?lm blowing. 2. Product qualities: Ductility, low density, good electric insulation, corrosion resistance, surface quality.

Spis treści

Required Basic Achievements.- Kinetics and Structure Formation in Unloaded Quiescent Melts.- Flow Induced Processes Causing Oriented Crystallization.- Closing Remarks.

Blurb

The first book to explicitly focus on the processing of crystallizing polymers, it presents innovative research on diverse interfering processes to help clarify the subject. The first to address the unexpectedly strong interaction of three transport phenomena: heat transfer, momentum transfer (rheology) with crystallization kinetics. With many applications, most well-known crystalline structures are found in polymers like high and low density polyethylene, polypropylene, polybutene and their copolymers. Common problems such as anisotropic shrinkage, warping, and split fiber formation are covered. In addition to applications on amorphous polymers, attempts at numerical simulation on crystallizing polymers are also examined. A feeling for the origins of undesired orientations and frozen-in stresses often associated with the manufacturing process is provided to polymer chemists, applied physicists, rheologists, plastics engineers, mold makers and material scientists.