BPA diglycidyl ether

Monofunctional p-isopropenylphenyl cyanate was used with BPA/DC in a composition with BPA diglycidyl ether and Co naphthenate catalyst [80],... 

Solid epoxy resins can be made from the diglycidyl ether of bisphenol A (BPA) via a chain extension reaction with bisphenol A. Keeping bisphenol A as the limiting reagent assures the product will still be a bisepoxide. One equivalent of phenol reacts with one equivalent of epoxide as shown in Reaction Scheme 1. 

One of the methods for the synthesis of high molecular weight polyhydroxy ethers based on Bisphenol A is the base catalyzed polyaddition of the diglycidyl ether of Bisphenol A (BADGE) with Bisphenol A (BPA) in the melt or in solution (Scheme 1). 

TGA, dynamic thermal analysis (DTA) and infrared (IR) techniques have been used [11-13] to determine E and n of BPA and resorcinol based epoxies. Figure 3.3 shows the TGA derived curves for BPA and resorcinol-based epoxy resins. The replacement of the phenyl group between two glycidyl ether groups in resorcinol diglycidyl ether by a 2,2-diphenylpropyl group increased appreciably the maximum decomposition rate. 

Epoxy resins are a class of thermosetting resin materials characterised by two or more oxirane rings or epoxy groups within their molecular structure [35-38]. The commonest epoxy resin is the diglycidyl ether of bisphenol A (DGEBA), which is prepared by the reaction of epichlorohydrin (ECD) and bisphenol A (BPA) (Figure 2.12). 

Vinylester (VE) resins are prepared by an addition reaction between epoxy resin (difunctional or multifunctional) with an unsaturated carboxylic acid such as acrylic acid or methacrylic acid [77]. The simplest form of VE is the product of the reaction between one mole of diglycidyl ether of BPA and 2 moles of methacylic acid (Figure 2.21). The reaction is carried out at about 100 °C using a catalyst such as triphenyl phosphine. To stop the polymerisation of methacylic acid, an inhibitor such as hydroquinone is used. By changing the nature of base epoxy resin, various types of VE resins can be produced. The vinyl-ended prepolymer is then dissolved in styrene to produce a polymerisable resin similar to an unsaturated polyester resin. Styrene content is adjusted to provide a wide range of viscosities, typically 0.1-4 Pa-s. 

The monomer BisGMA may be obtained by either the reaction of bisphenol A (BPA) and glycidyl methacrylate (GMA), or the reaction of the diglycidyl ether of bisphenol A (DGEBPA) and methacrylic acid (MA). The following reactions take place ... 

The most common hydroxyl-containing compound used to prepare epoxy resins is bisphenol A (BPA), which reacts with epichlorohydrin to produce, via the following reactions, diglycidyl ethers ... 

The preparation of the lowest member of the series, the diglycidyl ether of BPA, from epichlorophydrin (ECH), BPA, and sodium hydroxide can be represented as follows ... 

From a mechanistic point of view, the reaction has been clearly demonstrated to consist of two separate sequential steps, the first catalyzed by sodium hydroxide and the second involving sodium hydroxide as a reactant. In commercial practice, sodium hydroxide in excess of catalytic amounts is present from the start, and the preparation is conducted as though it were a one-step process. Under these conditions, the ECH and the diglycidyl ether of BPA are in competition for the as yet unreacted BPA. As a consequence, some higher homologues are always produced ... 

Molecular weights of these polyethers were examined by GPC in THF at 30 C (using the calibration curve of polyethers formed from BPA and diglycidyl ether). The results are in good agreement with the M values determined from the chlorine content of polymers as shown in Table 2. 

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