Preparation of Epoxy Resins from Bisphenol A and Epichlorohydrin

Example 4.24 Preparation of Epoxy Resins from Bisphenol A and Epichlorohydrin 

Safety precautions Before this experiment is carried out. Sect. 2.2.5 must be read as well as the material safety data sheets (MSDS) for all chemicals and products 

Under similar conditions to those used in (a), 22.8 g (0.1 mol) of bisphenol A, 5.55 g (0.14 mol) of NaOH (dissolved in 56 ml water), and 11.3 g (0.123 mol) of epichlorohydrin are allowed to react with one another. Because of the smaller molar ratio of epichlorohydrin to bisphenol A (1.22) the resulting epoxy resin is of higher molecular weight than that produced in (a). The epoxy value is approximately 0.1, corresponding to 1.44 epoxy groups per molecule of resin (equivalent weight 

The equivalent weight is the amount of resin that contains one equivalent of epoxide this is equal to 100/epoxy value. 

With an amine After determining the epoxy value and equivalent weight of the resin prepared according to (b), a small sample is melted in the oven at 150°C with the equivalent amount (0.25 mol per mol epoxy groups) of finely powdered 4,4 -methylenedianiline and the mixture well stirred for 30 s. After heating for 1 h at 150°C, the sample is taken out it has now become insoluble and infusible. 

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