Toughened-hybrid epoxies : influence of the rubber-phase morphology on mechanical properties

• Published in: Journal of materials science Vol. 29; no. 9; pp. 2481 - 2486
• Main Authors: VALLO, C. I, LIJIANG HU, FRONTINI, P. M, WILLIAMS, R. J. J
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01-05-1994
• Subjects: Applied sciences; Exact sciences and technology; Mechanical properties; Organic polymers; Physicochemistry of polymers; Properties and characterization; Epoxy resin; Mechanical properties; Property structure relationship; Morphology; Elastomer; Modified material
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/bf00363443

A toughened-epoxy polymer based on diglycidylether of bisphenol A (DGEBA) cured with ethylenediamine (EDA) and modified with a rubber based on an epoxy-terminated acrylontirile-butadiene random copolymer (ETBN), exhibited different morphologies depending on the rubber content. Up to 10% rubber, the morphology consisted of a random dispersion of spherical domains rich in rubber, while at 15% rubber, large and irregular domains were present, turning into a co-continuous structure at 20% rubber. Mechanical properties (elastic modulus, uniaxial compression yield stress, critical stress intensity factor, K sub Ic and strain energy release rate, G sub Ic ) of the toughened epoxies and hybrid-particulate materials containing glass beads, were analysed. The best mechanical properties were exhibited by hybrids with a random dispersion of rubbery domains in the epoxy matrix. The presence of large and irregular domains or co-continuous structures led to materials with poor mechanical properties.