摘要:

AbstractProcess developments in reactive extrusion or reactive compounding are largely carried out in closely intermeshing corotating twin‐screw extruders. The aim of this article is to present an analytical process model for this reactor type in order to facilitate the design of screw geometry and the settings of process parameters. Taking simultaneously into account aspects of flow behavior, heat transfer, thermodynamics, physics, and chemistry, a powerful mathematical model has been developed which was compared with practical results (e.g., residence time, pressure buildup, drive energy, bulk temperature, and conversion) on lab and production scale machines. The experiments were mostly carried out for the anionic bulk polymerizations of nylon 6 and polystyrene. Furthermore the reactive blending of nylon 6 and polyethyleneterephthalate was examined. Based on these chemical systems the practical use of computer‐aided process design will be discussed. © 1995 John Wiley&Sons,

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe use of newly developed polymer processing technologies to enable the microstructure control of nonreactive and reactive polymer systems, which up to now have been manufactured with conventional chemical polymerization processes, has been rapidly becoming popular, particularly in the field of polymer alloy systems. In this article the mechanisms of morphological development and its control for polymer alloys used mostly in a twin‐screw extruder have been reviewed mainly from our studies. And furthermore, on‐line monitoring and handling techniques developed at The Japan Steel Works are described in relation to the evolution of microstructure of polymer systems in a twin‐screw extruder. © 1995 John Wiley&Son

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA finite element code to simulate the thermoforming process was developed. A dynamic approach, a membrane hypothesis, and a second order explicit integration method were considered in developing the code. Tensile tests were carried out on a servohydraulic Instron device to validate hyperelastic and memory integral constitutive laws. An original experimental approach was designed and built to measure the displacement of the surface of the sheet at several points during the forming stage. A validation mold was instrumented to measure the in‐mold pressure profile during the forming process. Some preliminary attempts were carried out to consider the transient sheet heating stage and to evaluate its influence on the subsequent forming step. © 1995 John Wiley&Sons, I

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractIn recent years, the notion of the expert system (ES) has become very popular, and its enormous potential to industry and ways in which it could improve decision‐making have been recognized. This article presents the research work of an expert system (ESIMCOST) the authors developed to assist the manufacturers in the injection mold cost estimation at the early product design stage. The system domain is concerned with the concurrent decision‐making of the plastic part design, injection mold design, and mold‐making process planning during the cost estimation process. Numerous interrelated variables and technical data for estimating the injection mold cost are well organized. With the inputs of the features of a plastic part, the ESIMCOST will generate an estimated cost of the injection mold required to produce the part. Some of the projected benefits from the system implementation are addressed in the article. © 1995 John Wiley&Son

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractWeld lines are known to present serious problems, especially in injection molding processes. They usually represent the weakest region in a molded part in terms of mechanical properties. They are also known to be even weaker in the case of blends. In this work, the mechanical properties and the morphology of injection molded polycarbonate (PC), high‐density polyethylene (HDPE), and their blends (PC/PE) were investigated. This typically immiscible blend was compatibilized by the addition of small amounts (<5% by weight) of ethylene vinyl acetate copolymer (EVA) containing 60% by weight vinyl acetate. The modified and nonmodified blends were injection molded in the presence of weld lines using a double‐gate dogbone‐shaped tensile bar mold. The weld line strength and its morphology were investigated as a function of injection temperature. In the case of pure polycarbonate, the weld line strength was found to be very sensitive to injection temperature whereas for polyethylene no difference was observed between the strength of the nonwelded and the welded specimens. For the 80/20 PC/PE blend, the weld line strength is lower compared to that of the blend components. The addition of less than 1% of EVA increased the strength of the weld line above that of the neat blend. The morphology of the nonmodified blend was similar to that of a typical immiscible blend (i.e., PE spheres dispersed in a rigid matrix of PC). However, addition of the copolymer to the blend resulted in a better phase dispersion and finer PE particles. In addition, the V‐notch in the middle of the sample was greatly reduced by the addition of the copolymer. This was experimentally investigated by scanning electron microscopy in the region of the weld line. © 1995 John Wiley&S

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractEnhanced compatibility for blends of polycarbonate with high‐density polyethylene has been achieved with the addition of 5 wt% compatibilizers composed of 1 : 1 mixtures of phenoxy and the sodium ionomer of an ethylene methacrylic acid copolymer at two different levels of neutralization. Both components of the compatibilizer have been found to be capable of reacting with the polycarbonate phase to produce branched polymer chains. These impart a degree of compatibilization in polycarbonate/high‐density polyethylene blends, however at higher levels of sodium in the compatibilizer the polycarbonate phase undergoes crosslinking reactions, causing severe embrittlement. Compatibilization effects are confirmed by morphological examinations, dynamic rheological data, and dielectric loss spectra. © 1995 John Wiley&Sons,

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractMost plastics are produced from oil and have a high potential as hydrocarbon sources for the chemical industry. Pyrolysis is a practicable way to pyrolyze mixed plastics. The fluidized bed pyrolysis has turned out to be particularly advantageous. Twenty‐five to 45% of product gas with a high heating value and 30–50% of an oil rich in aromatics could be recovered. The oil is comparable to that of a mixture of light benzene and bituminous coal tar. Up to 60% of ethene and propene are produced by using mixed polyolefins as feedstock. Under appropriate conditions the pyrolysis could be successful on the market. © 1995 John Wiley&Sons,

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:0730-6679    

DOI:10.1002/adv.1995.060140408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY