Item – Theses Canada

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OCLC number
1006668981
Author
Pop-Iliev, Remon,1958-
Title
Processing of fine-cell polypropylene foams in compounding-based rotational foam molding.
Degree
M.A. Sc. -- University of Toronto, 1999
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, [2000]
Description
3 microfiches
Notes
Includes bibliographical references.
Abstract
This thesis is intended to provide a scientific and engineering understanding of the technological potentials for processing fine-cell PP foams by using a compounding approach in rotational foam molding. The presented research includes a proposal for a process designed for transforming polypropylene (PP) resins into completely foamed, single-layer, single-piece useful products. The proposed process comprises dispersing a chemical blowing agent (CBA) in the PP matrix in a twin-screw compounder, pelletizing the obtained expandable composition, and using the pre-compounded pellets for foam production in one uninterrupted rotational foam molding cycle. Four types of PP resins were selected with melting flow rates (MFR) ranging from 5.5 to 35 dg/min. The PP resins and the CBA were characterized using thermal analysis instrumentation, a differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA). Using different formulations, four types of pellets were compounded with a CBA from each type of PP resin for conducting rotational foam molding experiments using an uni-axial lab-scale rotational molding machine. A scanning electron microscope (SEM) was used to characterize the quality of the compounded PP pellets. The optimal processing strategies for six-fold and three-fold PP fine-cell foaming were identified via a systematic experimental parametric search. By using time-temperature profiles, recorded using a data acquisition device, the process was characterized and strategies for process improvements were established. Best foams were obtained by using the highest viscosity resins.
ISBN
0612456226
9780612456228