Addition of H₃PO₄ to diglycidyl ethers of bisphenol A: Kinetics and product structure

Abstract

The preparation of the addition products of H 3 PO 4 to bisphenol A based epoxy resins is described. These products are considered modifiers of the epoxy resins and for the further formation of useful networks (coatings and related products). Depending on the ratio of H 3 PO 4 to epoxy groups and other reaction variables, a family of oligomers with acidic end groups has been formed. The major reaction is the addition of H 3 PO 4 to epoxy groups. Among the side reactions, the acid-catalyzed addition of the >CHÀ ÀOH (and/or À ÀCH 2 OH) groups to epoxy groups dominates. The À ÀOH groups, if not present in the starting resins, are emerging from the PÀ ÀOH to oxirane ring addition. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of the starting epoxy resins has revealed their structural diversity. In the kinetic measurements and determination of the ester composition, diglycidyl ether of bisphenol A (BADE) as a model compound has been mostly applied. The kinetics of the H 3 PO 4 -BADE reaction is described, and the structures of the final products are analyzed with 31 P{ 1 H}-NMR, which gives (at pH $ 12) quantitatively the proportions of the monoesters, diesters, and triesters as well as the unreacted H 3 PO 4 . The conditions have been found leading exclusively to the monoester, and this indicates that an increase in the reaction temperature enhances the selectivity of the reaction; that is, it depresses the proportion of the acid-catalyzed À ÀOH and epoxy group reaction.

Improvement of the interfacial shear strength of poly(p‐phenylene benzobisoxazole) fiber/epoxy resin composite via a novel surface coating agent

“…Figure shows the 31 P NMR spectrum of PCO, which was silylated by the addition of hexamethyldisilazane to distinguish the structural units. In the 31 P NMR spectra, the signals of the ester after silylation can be reported as follows: [(CH 3 ) 3 SiO] 3 PO at −25 ppm, [(CH 3 ) 3 SiO] 2 P(O)OR at −17 to −18 ppm, and [(CH3) 3 SiO] P(O)(OR) 2 at −7 ppm . As can be seen from Fig.…”

Reactions of H3PO4 forming polymers. Apparently simple reactions leading to sophisticated structures and applications

“…Dependence of the ratios of various esters on the starting [H3PO4]0/[epoxy group]0 ratio (1,4-dioxane, at 25 • C) in reaction with DGEBA (all products are soluble) a [94].…”

“…Partial or complete modification of epoxy resins by phosphoric acid is also of interest, therefore structures of reaction products of DGEBA with H 3 PO 4 were studied as a function of the [H 3 PO 4 ] 0 /[DGEBA] 0 ratio [94], with the results given in Table 3.…”

Polymers with Esters of Phosphoric Acid Units: From Synthesis, Models of Biopolymers to PolymerInorganic Hybrids

“…The modification of epoxy resins and the formation of esters of phosphoric acid provides a new family of products that by themselves or as additives can be applied to coatings and related final products. Depending on the ratio of H 3 PO 4 to the diglycidyl ether of bisphenol A, for example, products differing in the ratio of monoesters (end groups), diesters (repeating units), and triesters (branching points) were obtained (Table 2) 52…”

“…Therefore, the excess of H 3 PO 4 can be separated and H 3 PO 4 could be regenerated, ready for the next reaction. When the polyaddition was conducted at 100 ○ C, a slightly lower ratio of H 3 PO 4 /epoxy group (≈9 : 1) was needed to prepare exclusively the product free of triesters 52…”