Dynamic mechanical properties of epoxy resin/epoxidized rubber blends: Effect of phase separated rubber

Abstract

The dynamic mechanical properties of blends of diglycidyl ether of bisphenol‐A‐based epoxy resin and internally epoxidized polybutadiene rubber have been studied. It is shown that the influence of the composition of the continuous phase and of the dispersed phase can be studied not only from the variations of the glass transition temperature but also from the changes in the apparent enthalpy of activation associated with this transition. As the initial rubber content increases, the composition of the dispersed phase remains practically constant while more rubber is able to dissolve in the continuous phase. Analysis of the rubbery plateau region reveals that the shear modulus of the blends is not much affected by the presence of dissolved rubber in the continuous phase but strongly depends on the volume fraction of dispersed phase. This volume fraction can be obtained from the relative drop in shear modulus after modeling the results with the Kerner equation. The results compares well with independent measurements by scanning electron microscopy. © 1994 John Wiley & Sons, Inc.

Poly(hydroxyether of bisphenol A)-block-polydimethylsiloxane alternating block copolymer and its nanostructured blends with epoxy resin

“…One of the successful routines of toughness improvement is to incorporate polymeric modifiers into thermosetting matrix to form fine morphological structures. The effective polymer modifiers can be elastomers [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] or thermoplastics [18][19][20][21][22][23][24][25]. Liquid elastomers such as carboxyl-terminated butadiene-acrylonitrile rubber (CTBN), amine-terminated butadiene-acrylonitrile rubber (ATBN) [3][4][5][6][7] have been exploited for toughness improvement.…”

“…However, the presence of unsaturated structure in these liquid elastomers is prone to thermal instability and low oxidation resistance. By comparison, organosilicon polymers (e.g., polydimethylsiloxane) possess some superior properties, such as thermal stability, moisture resistance and good electrical properties and thus are more advantageous modifiers [5,[8][9][10][11]13]. However, polysiloxanes have poor compatibility with the precursors of epoxy due to the big difference in solubility parameter, which is essential for the formation of fine phase-separated structures in thermosets [27].…”

Miscibility and mechanical properties of tetrafunctional epoxy resin/phenolphthalein poly(ether ether ketone) blends

“…One of the most successful methods of improving the toughness of ERs is to incorporate a second phase of dispersed rubbery particles into the crosslinked polymer. [5][6][7][8][9][10][11][12][13][14][15][16][17] In these systems, toughening is considered to arise mainly from shear deformation in the matrices and the presence of rubber particles. 9,18 -20 Unfortunately, the addition of rubbery materials to ERs has been shown to lower their glass transition temperatures (T g 's) and thermal and oxidative stability while enhancing their fracture toughness.…”

Epoxy/anhydride networks modified by epoxy/anhydride oligomers containing SiOH groups

“…For an epoxy resin plasticized by an internally epoxidized polybutadiene rubber, a value of k ϭ 2.0 was reported. 12,13 An increase in the k value corresponds to an increase in T g E Ϫ T g (higher plasticization effect). Let us assume that a T g of 330 K is acceptable for a particular application of the plasticized epoxy, for example, for a coating, adhesive, or sealant.…”