Preparation of 4‐(4‐hydroxyphenoxy)phenol diglycidyl ether with improved toughness behavior

Abstract

A high‐performance difunctional epoxy resin, 4‐(4‐hydroxyphenoxy)phenol diglycidyl ether (DHPOP), was synthesized by a two‐step method. The curing behavior of DHPOP was investigated by nonisothermal differential scanning calorimetry method and the curing kinetics results revealed that the introduction of ether linkage could improve the activity of epoxy groups, leading to a lower curing temperature and apparent activation energy compared with that of the commercial bisphenol‐A diglycidyl ether (DGEBA). A series of copolymers were then prepared by varying the mass ratio of DHPOP and DGEBA, which were cured with 4,4′‐diaminodiphenyl methane. The effect of DHPOP contents on thermal and mechanical properties and fracture morphology was studied. As expected, with the increase of DHPOP in the network, the impact strength and char yield were significantly enhanced, while the glass transition temperature (Tg) remained unchanged because of the increase of crosslink density. The excellent toughness endows the DHPOP with the promising potential for the application as high‐performance resin matrix. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46458.

Multifunctionality in Epoxy Resins

“…48 Toughness and stiffness enhancement resulting from the synergistic effect of the rigid aromatic rings and the flexible ether linkages in the epoxy backbone were also reported and found to have not compromised the thermal and mechanical properties of thermosets; paving the way for synthesis of monomers containing such modifications. 49,50 The effect of crystalline domains in the polymer chains as well as the effect of liquid crystal mesogens in the backbone of polymers also showed improvements in toughness and on other mechanical properties in epoxy resins. 51,52 In categorizing different ways of toughening epoxy resins, the succeeding approaches can fall in any of the following categories: (1) in sub-atomic level (modifying the molecules and using additives or micelles), (2) atomic level (crystalline structures and short-range vs. long-range order), and (3) microscopic level (introducing fibers to make isotropic vs. anisotropic composites).…”

Effect of aromatic substitution on the cure reaction and network properties of anhydride cured triphenyl ether tetraglycidyl epoxy resins

“…Unfortunately, this is exacerbated for high‐performance applications, where higher strength, modulus, and glass transition temperatures necessitate even more highly crosslinked networks. Indeed, this need continues to drive the search for new resin systems and monomer with improved performance and better composite materials …”

“…Indeed, this need continues to drive the search for new resin systems and monomer with improved performance and better composite materials. [10][11][12][13] The benchmark epoxy resin for high-performance composites today is the tetrafunctional epoxy resin, tetraglycidyl diamino diphenyl methane (TGDDM) that produces network polymers with superior mechanical and thermal properties but unfortunately is very brittle.…”