Chinese Journal of Polymer Science

, Volume 36, Issue 5, pp 632–640 | Cite as

Preparation and Characterization of DGEBA/EPN Epoxy Blends with Improved Fracture Toughness

  • Morteza Khalina
  • Mohammad Hosain Beheshty
  • Ali Salimi


The physical and mechanical properties of blends composed of two kinds of epoxy resins of different numbers of functional groups and chemical structure were studied. One of the resins was a bifunctional epoxy resin based on diglycidyl ether of bisphenol A and the other resin was a multifunctional epoxy novolac resin. Attempt was made to establish a correlation between the structure and the final properties of cured epoxy samples. The blend samples containing high fraction of multifunctional epoxy resin showed higher solvent resistance and lower flexural modulus compared with the blends containing high fraction of bifunctional epoxy resin. The epoxy blends showed significantly higher ductility under bending test than the neat epoxy samples. The compressive modulus and strength increased with increasing of multifunctional epoxy in the samples, probably due to enhanced cross-link density and molecular weight. Morphological analysis revealed the presence of inhomogeneous sub-micrometer structures in all samples. The epoxy blends exhibited significantly higher fracture toughness (by 23% at most) compared with the neat samples. The improvement of the fracture toughness was attributed to the stick-slip mechanism for crack growth and activation of shear yielding and plastic deformation around the crack growth trajectories for samples with higher content of bifunctional epoxy resin as evidenced by fractography study.


Epoxy Blend Functionality Mechanical property Toughness 


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Copyright information

© Chinese Chemical Society, Institute of Chemistry, Chinese Academy of Sciences and Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Morteza Khalina
    • 1
  • Mohammad Hosain Beheshty
    • 1
  • Ali Salimi
    • 2
  1. 1.Department of CompositesIran Polymer and Petrochemical InstituteTehranIran
  2. 2.Department of Resin and AdhesivesIran Polymer and Petrochemical InstituteTehranIran

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