ISSN:0730-6679    

DOI:10.1002/adv.1983.060030201

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

年代:1983

数据来源: WILEY

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030202

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

年代:1983

数据来源: WILEY

摘要:

AbstractA miniaturized version of a recently developed apparatus has been constructed to measure both the thermal conductivity and thermal diffusivity of polymer melts and solids. The apparatus was employed to measure the thermal conductivity and diffusivity of a number of polyethylene resins of varying density and molecular weight distribution. The results obtained with the miniaturized unit are in good agreement with those obtained with the original larger apparatus. Moreover, the dependence of thermal conductivity and diffusivity on temperature, resin density, and molecular weight parameters has been evaluated with the aid of the new apparatus. Empirical relationships involving the quantity (MwMn)1/2have been found for the dependence of thermal conductivity and diffusivity on molecular weight.

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030203

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

年代:1983

数据来源: WILEY

摘要:

AbstractCo‐rotating, self‐wiping, twin‐screw extruders are being recognized as efficient horizontal mixers for performing continuous reactions and polymerizations. Many processes which previously required large batch type tanks for sufficient residence times can achieve similar yields and be replaced with much smaller equipment due to the greater efficiency of mixing. The use of co‐rotating, self‐wiping, twin‐screw extruders for continuous polymerization processes, especially on a laboratory development scale, will play a more important role in the future as their versatility in these processes is

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030204

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis paper discusses the development and verification of a finite element heat transfer computer program which can simulate a PVC pipe extrusion process. The simulation is broken down into seven phases which represent various thermal conditions throughout the process.

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030205

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

年代:1983

数据来源: WILEY

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030206

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

年代:1983

数据来源: WILEY

摘要:

AbstractChanges in air quality standards and new polymer manufacturing technologies have renewed interest in polymer melt devolatilizing. Unfortunately, little data is available to aid in the design and scale up of melt devolatilizing single‐screw extruders.As part of the ongoing development activities of Farrel Company, melt devolatilizing in various devices has been under study for a number of years. In order to be able to develop analytical methods of predicting performance and scaling up from small scale test stands, some elementary devolatilizing studies were carried out. Theoretical predictions based on classical diffusion theory were compared with actual results, leading to a revised model of the actual melt devolatilizing process. Based on this revised model, several novel single screw devolatilizing concepts were proposed, built and tested. In this paper, we are presenting some of the theoretical work underlying these studies as well as test results on conventional single‐screw devolatilizing sections. We hope to be in a position to divulge additional information on some of the novel devolatilizing devices at the time of the presentation of the pa

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030207

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

年代:1983

数据来源: WILEY

摘要:

AbstractOne of the primary factors to consider during an injection molding cycle is the judicious switch‐over from HIGH to HOLD injection pressure setting. Historically, this switchover was effected either as a function of time or ram position. Unfortunately, neither of those parameters correlated satisfactorily to the processing event that was supposed to be detected, i.e., the “packing” of molten polymer in the mold. There are several IMM Process Controllers that directly sense rate of change of cavity pressure, but these require special transducers to be inserted in the mold. This paper describes a scheme that uses the feedback of injection ram velocity to determine mold packing and the resulting optimum point at which pressure switchover should be init

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030208

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe thickness distribution in a blow molded product depends on swelling and sagging of the extruded parison. In this paper, the extensional deformation during parison formation process has been described theoretically, using a swelling function and Jeffrey's equation for material viscoelasticity. The heat balance equation has been solved simultaneously to treat the more general case of parison being exposed to ambient conditions. Experiments were carried out on a commercial blow molding machine with three polymers and, in each case, parison deformation was recorded on a videotape. The experimental results of parison sagging and the theoretical results have shown good agreement.

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030209

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

年代:1983

数据来源: WILEY

ISSN:0730-6679    

DOI:10.1002/adv.1983.060030210

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

年代:1983

数据来源: WILEY