Theoretical Background and Automation Approach for a Novel Measurement Method for Determining Dynamic Solubility Limits of Supercritical Fluids in Injection Foam Molding

In terms of sustainability, injection foam molding gains in importance. Yet still many questions throughout the whole process remain unanswered. Especially, the conditions inside the cylinder during gas injection are fraught with uncertainty. Our development of a new methodology for the determinatio...

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Bibliographic Details
Published inPolymer engineering and science Vol. 60; no. 2; pp. 330 - 340
Main Authors Kastner, Clemens, Steinbichler, Georg
Format Journal Article
LanguageEnglish
Published Hoboken, USA John Wiley & Sons, Inc 01.02.2020
Society of Plastics Engineers, Inc
Blackwell Publishing Ltd
Subjects
Automation
Bulk modulus
Computational fluid dynamics
Cylinders
Gas injection
Gas mixtures
Injection molding
Injection molding machines
Machinery industry
Measurement
Methodology
Methods
Novels
Plastics machinery
Polymer industry
Polymers
Propylene
Questions
Solubility
Supercritical fluids
Sustainable development
Test procedures
Austria
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Summary:In terms of sustainability, injection foam molding gains in importance. Yet still many questions throughout the whole process remain unanswered. Especially, the conditions inside the cylinder during gas injection are fraught with uncertainty. Our development of a new methodology for the determination of dynamic solubility in injection foam molding helps to answer the most basic question regarding gas loading: Using the bulk modulus of the polymer–gas mixture, the dynamic solubility limit can be detected. In a first series of tests, the methodology was verified with simultaneous ultrasonic measurements—an excellent agreement was observed. In this work, a second, more thorough test series is presented. Using the bulk modulus methodology on different polypropylene grades, dynamic solubility limits between 0.62 and 2.56 wt% nitrogen at pressures between 80 and 200 bar and a temperature of 230°C were determined directly on an injection molding machine. The detailed theoretical background for this technique, as well as a mathematical automation approach, is provided. This innovative yet simple method yields novel insights on process limits and provides the possibility of an a priori machine setup or a fully automatic self‐adjustment of the machine. POLYM. ENG. SCI., 60: 330–340, 2019. © 2019 The Authors. Polymer Engineering & Science published by Wiley Periodicals, Inc. on behalf of Society of Plastics Engineers.
ISSN:0032-3888
1548-2634
DOI:10.1002/pen.25288