摘要:

AbstractCurrently, the selection of elements and operating conditions in the mixing of various materials in a corotating twin screw extruder is an art which requires previous experimental studies. In this report, we outline various experimental and theoretical tools developed to investigate the mixing process in a fully intermeshing corotating twin screw extruder. The thermomechanical history of mixing is simulated employing the finite element method. To verify the numerical findings, experimental techniques were developed to investigate the goodness of mixing of samples collected from a 50.8 mm, “clam shell” design, Baker‐Perkins twin screw ext

ISSN:0730-6679    

DOI:10.1002/adv.1988.060080401

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

年代:1988

数据来源: WILEY

摘要:

AbstractA new software concept for an integrated computer‐aided design procedure for injection‐molded parts is presented. This software has been developed in close cooperation with the plastics industry and therefore takes into consideration, to a very high degree, requirements arising from practical use. The resulting program, named CADFORM, links commercial and newly developed plastics‐specific software and thus enables all the steps involved in designing a new molding and the corresponding mold to be carried out within one program s

ISSN:0730-6679    

DOI:10.1002/adv.1988.060080402

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

年代:1988

数据来源: WILEY

摘要:

AbstractA computerized automatic die swell apparatus has been designed and constructed. The apparatus provides both digital and analog outputs regarding the diameter of the molten extrudate and its variation with time. Precautions are made to reduce the effects of gravitational sag and temperature changes. The apparatus was used in conjunction with an Instron capillary rheometer to measure the transient and equilibrium extrudate swell behaviour of five low density polyethylene resins, a short fiber glass filled polypropylene melt, and a thermotropic liquid crystal polymer.

ISSN:0730-6679    

DOI:10.1002/adv.1988.060080403

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

年代:1988

数据来源: WILEY

摘要:

AbstractFlow visualization of a scaled down rubber compounding process in an internal mixer is described. The mastication of scaled down rubber bales, and the addition of carbon black and oil were studied. The times required for rubber bale ‘pickup’ by the rotors as well as bale homogenization time were determined for various elastomers. The times required to incorporate black and oil were measu

ISSN:0730-6679    

DOI:10.1002/adv.1988.060080404

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

年代:1988

数据来源: WILEY

摘要:

AbstractUsing the melt blending procedure, various compositions of polycarbonate and poly(ethylene terephthalate) were compounded. Some of the blends were extruded and then injection‐molded, while others were directly injection‐molded into ASTM bars for physical testing. When the properties of these blends were compared, variations in values were obtained for blends of the same composition. Variations in properties were higher in blends containing less than 70% PET content. At 70% PET and above, there were negligible differences between blends of the same composition processed by different methods. Since it has been established that blends with more than 70% PET are miscible, it can be concluded that injection molding can be applied to mix miscible blends into final parts directly without a preliminary extrusion blending proc

ISSN:0730-6679    

DOI:10.1002/adv.1988.060080405

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe wear and frictional behaviour of self‐lubricating polymer composites was investigates by means of tribological testing and microstructural examination. The tribological testing consists of wear rate measurement and frictional coefficient determination as a function of sliding velocity and normal load for two‐body abrasion and adhesive sliding tests. A new insight has been provided for the concept of “contact strenght” and related to the wear data using the appropriate wear equation developed from the crack propagation and damage accumulation

ISSN:0730-6679    

DOI:10.1002/adv.1988.060080406

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

年代:1988

数据来源: WILEY

摘要:

AbstractRheological characterization, extrudate swell measurements, and a flow marker extrusion study for several elastomers and their compounds is reported. The materials included natural rubber (NR), styrene–butadiene rubber (SBR), ethylene–propylene terpolymer (EPDM), and polychloroprene (CR) and their carbon black compounds. The shear viscosity was measured with a sandwich rheometer, a shearing disk viscometer, and a capillary rheometer over a wide range of shear rates. Evidence for yield values is found in compounds with 0.20 and 0.30 levels of carbon black. Empirical equations were fit to the data. Extrudate swell measurements were carried out for slit and capillary dies. Increasing the level of carbon black reduces the level of swell. Flow marker experiments were carried out in the barrel of a capillary rheometer using a wide range of die designs. These indicated roughly radial streamline flows into the capillary or slit land. Recessed parts of a die could accumulate stagnant material. Evidence for wall slippage in the rheometer barrel for compounds with 0.20 and 0.30 volume fractions of carbon black is discus

ISSN:0730-6679    

DOI:10.1002/adv.1988.060080407

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

年代:1988

数据来源: WILEY