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Can I read Influence of Two-step Process and of Different Stoichiometric Ratios on Morphologies Generated in Castor Oil Epoxy Resins on EtoBox?
Influence of Two-step Process and of Different Stoichiometric Ratios on Morphologies Generated in Castor Oil Epoxy Resins by Jorge L. Sanchez; Carmen C. Riccardi is a Materials Science article available to read on EtoBox.
What is Influence of Two-step Process and of Different Stoichiometric Ratios on Morphologies Generated in Castor Oil Epoxy Resins about?
## Abstract Phase separation during polymerization was studied in a model system consisting of a diepoxide based on diglycidyl ether of bisphenol A (DGEBA), variable amounts of ethylenediamine (EDA) and the mass of castor oil (CO) necessary to obtain a mass fraction equal to 0‐15 in a final system where the stoichiometric ratio of amine to epoxy equivalents, __r__, was equal to 1. A two‐step polymerization process was performed by curing first a system with __r__ = 0‐5, during variable times before phase separation, and then carrying the system to __r__ = 1. Thermodynamic analysis of samples with different __r__ values led to a linear relationship between the Flory‐Huggins interaction parameter and __r__. The concentration (__P__) and average size (D̄) of dispersed‐phase particles followed opposite trends, i.e. __P__ increased while D̄ decreased, when either __r__ was increased or the time of curing in the first step of a two‐step process was decreased. This was explained by assuming that the competition between nucleation and growth was determined by the viscosity at the cloud point, η~cp~. Low values of η~cp~ favoured growth over nucleation and led to fewer but larger particles.
Who reads Influence of Two-step Process and of Different Stoichiometric Ratios on Morphologies Generated in Castor Oil Epoxy Resins?
It is typically read by researchers, students, and practitioners in Materials Science.
- Author
- Jorge L. Sanchez; Carmen C. Riccardi
- Publisher
- John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Inc.; Wiley (ISSN 0959-8103)
- Published
- 1993
- Language
- EN
- Field
- Materials Science (Physical Sciences)