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A study of the dynamics of foam growth: Simplified analysis and experimental results for bulk density in structural foam molding
Author(s) -
Amon Moris,
Denson Costel D.
Publication year - 1986
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760260311
Subject(s) - materials science , bubble , coalescence (physics) , composite material , molding (decorative) , thermoplastic , mechanics , physics , astrobiology
A cell model describing the diffusion‐induced growth of closely spaced single bubbles developed in an earlier publication is now used as the microscopic building block of an analysis of low‐pressure structural foam molding. Heat transfer, solidification, and bulk flow of the foam in the mold cavity are included in this macroscopic analysis. An experimental method is described whereby the bulk density of an expanding thermoplastic polymeric foam is measured as a function of time when the expanding foam is prepared by the short shot injection molding process. Instantaneous and final bulk foam density data obtained for various values of the controlling process parameters are compared with the predictions of the model. These predictions are found to be in qualitative agreement with the experimental measurements reported here. However, quantitative differences exist between the two. These differences are explained mainly by the omission of melt elasticity and bubble coalescence in the model.