Facile strategy and mechanism of greatly toughening epoxy resin using polyethersulfone through controlling phase separation with microwave‐assisted thermal curing technique

Abstract

Toughening has been the essential issue for developing high‐performance thermosetting resins. Herein, starting from polyethersulfone (PES) and bisphenol A epoxy resin (EP), a facile strategy is developed to prepare tough resins through controlling phase structure with microwave‐assisted thermal curing. PES/EP resins cured with the assistance of microwave curing (m‐PES/EP) have two major differences compared with those using traditional heat curing (t‐PES/EP), one is high degree of phase separation, and the other is phase separation mechanism. Initial phase separation of all t‐PES/EP resins follows spinodal decomposition mechanism, while those of m‐PES/EP systems with 8 wt% and 18 wt% of PES follow nucleation and growth mechanism. These differences are derived from the fact that microwave curing has much faster phase separation rate and curing reaction rate than thermal curing owing to the higher thermal effect. Differences in phase structure bring different macro performances, and m‐PES/EP systems have higher impact strengths, fracture toughnesses, and flexural strengths than t‐PES/EP resins. This investigation provides a facial and effective way of developing higher performance thermoplastic/thermosetting resin system through controlling phase structure. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48394.

Improving the toughness of polycyanate ester by adding epoxy pre‐polymer with different molecular weights

“…Double peaks appear in the tan δ curve of PreEP/CE (Figure 5a), indicating that the PreEP phase (T g1 ) and CE phase (T g2 ) are formed in the PreEP/CE system. [20,47] Meanwhile, the distance (ΔT g ) between the two peaks of the curve increases from 9.5 C for 0.1 PreEP/CE to 19.4 C for 0.4 PreEP/CE ( Table 1). The half-peak width of the curve for the different systems also increases from 26.5 C for EP/CE to 43.8 C for 0.4 PreEP/CE (Table 1).…”

“…[18,19] This can be used as a stress concentration source to absorb energy or cause plastic deformation. [20] There are three methods for building phase-separated structures in thermoset resin (cyanate ester). The first is to blend a thermoplastic polymer with a thermoset resin.…”

Effects of aramid nanofibers on the mechanical properties of epoxy resin and improved adhesion with aramid fiber

“…The stress concentrator is produced by the rubber dispersed phase, which induces the silver streak and shear deformation; [5,6] Thermoplastic materials, which have good toughness and high modulus and heat resistance, are used to modify EP to ensure its modulus and thermal stability. [7][8][9][10][11] The hyperbranched polymers refer to chemically induced phase separation and particle cavitation, which induce the stress concentration and shear deformation of EP to absorb more external energies. [12,13] Block copolymer, which has excellent compatibility with the resin group, can form a microphase nanostructure in the matrix resin self-assembly and achieve a toughening effect during the curing phase separation.…”

Phase separation of ternary epoxy/PEI blends with higher molecular weight of tertiary component polysiloxane

“…[4][5][6][7] Over the past a few decades, toughening epoxy and maintaining its high strength at the same time have always been an important subject. [8][9][10] A practical approach to toughen epoxy resins is to use thermoplastics with high glass transition temperature, excellent thermal stability and toughness, such as polysulfone (PSF), [11][12][13] poly(ether sulfone) (PES), [14][15][16] polyimides (PI) [17][18][19] and poly(ether imides) (PEI). [20][21][22] PEI with excellent mechanical properties can effectively improve the toughness of epoxy resin without sacricing other properties of epoxy resin and has been widely used as the modier of epoxy resin.…”