The effect of stoichiometry on chain segment and ion mobility in partially polymerized epoxy systems
作者:
Sue Ann Bidstrup,
Joycelyn O. Simpson,
期刊:
Journal of Polymer Science Part B: Polymer Physics
(WILEY Available online 1995)
卷期:
Volume 33,
issue 1
页码: 43-54
ISSN:0887-6266
年代: 1995
DOI:10.1002/polb.1995.090330105
出版商: John Wiley&Sons, Inc.
关键词: thermosets;epoxy resin;amine cross‐linking agents;free volume;rheology;dielectric analysis;viscosity;ionic conductivity;cure monitoring;chain segment mobility;ion mobility;glass transition temperature;weight average molecular weight
数据来源: WILEY
摘要:
AbstractThe temperature dependence of steady‐shear viscosity and ionic conductivity were measured for a series of unreacted mixtures and partially cured, ungelled samples of diglycidyl ether of bisphenol‐A (DGEBA) and an amine cross‐linking agent, diamino diphenyl sulfone (DDS). Six stoichiometric ratios of epoxide groups to amine hydrogens were examined. Free volume expressions were used to model the temperature dependence of the conductivity and viscosity for the unreacted DGEBA‐DDS mixtures. In addition, these expressions were combined to successfully correlate changes in viscosity and conductivity during the DGEBA‐DDS polymerization prior to gelation. It also was demonstrated that the change in weight average molecular weight during polymerization could be interpreted from the dielectric data. Through studying variations in the stoichiometry, it was possible to examine the effects of changes in chemical structure and ion concentration on the fitted parameters in the free volume models. The inherent ion transport factor (ζ0) was found to be inversely proportional to the concentration of ions in the test samples. The fractional free volume for segmental motion (B) was found to increase with an increase in the glass transition temperature and to be a function of the rigidity of the polymer. ©1995 John Wile
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