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Monohole flow test with high‐frequency preheating for evaluating flowability of thermosetting compounds
Author(s) -
Tonogai Saburo,
Seto Shoji
Publication year - 1981
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.760210508
Subject(s) - thermosetting polymer , materials science , inflection point , composite material , volumetric flow rate , water content , thermodynamics , mathematics , geometry , physics , geotechnical engineering , engineering
Abstract The flow behavior of molding compounds such as phenolics, melamines, and ureas was examined by a monohole flow test in which the compounds were high frequency‐preheated up to the test temperature just prior to being put into the monohole mold. The effect of temperature, pressure, and water content on the flowability has been clarified as follows: (1) The relation between log flow rate and reciprocal absolute temperature consists of two straight lines with different slopes, showing dual activation energies for flow above and below an inflection point. The phenomenon suggests the existence of a phase transition in a resin flow. (2) The inflection point shifts to the lower temperature side with an increase of pressure and water content. (3) The influence of water content on the flowability varies largely according to compatibility between resins and water. (4) The temperature dependence of flow rate in a urea compound decreases during storage due to the advancement of condensation.