Equivalent weight epoxy resin

Bisphenol F Resin. Bisphenol F [2467-02-9] epoxy resin is of the same general stmcture as the epoxy phenol novolaks. Bisphenol F is 2,2Emethylene bisphenol. Whereas the epoxy phenol novolaks vary from viscous Hquids to soHd materials, the bisphenol F resin has a low viscosity (ca 4 Pa-s (40 P)) and 165 epoxy equivalent weight. Its n value (degree of polymerization) is about 0.15 and crystallization, often a problem with low viscosity conventional bisphenol A resins, is reduced with the bisphenol F resin. 

The pure diglycidyl ether of bisphenol A [1675-54-3] DGEBA is a crystalline soHd (mp 43°C) with a weight per epoxide (WPE) = 170. The typical commercial unmodified Hquid resins are viscous Hquids with viscosities of 11—16 Pa-s (110—160 P) at 25°C, and an epoxy equivalent weight of ca 188. 

SoHd epoxy resins are sometimes designated as 1-, 4-, 7-, or 9-type resins these approximate the degree of polymerization. Commercial products are designated similarly, eg, Epon 1001, 1004, 1007, and 1009 (SheU Chemical Co.). The relationship between n value, epoxy equivalent weight, and melting point is shown in Table 5. 

The epoxide equivalent is a measure of the amount of epoxy groups. This is the weight of resin (in grammes) containing 1 gramme chemical equivalent epoxy. For a pure diglycidyl ether with two epoxy groups per molecule the epoxide... 

Amine-epoxy resin systems, 10 443 Amine equivalent weight (AEW), 10 399 Amine ethoxylates, 24 150-151 Amine extractants, 10 791 Amine functional curing agents,... 

Epoxy-DICY systems, 10 454 Epoxy equivalent weight (EEW), 10 399 Epoxy ester alkyd resins, 2 165-166 Epoxy esters, 10 380-384, 443 Epoxy formulations, performance of, 10 428 Epoxy groups, 10 567 hydrolysis of, 10 358 acid-catalyzed cross-linking of, 15 171 Epoxy molding compounds (EMC), 10 373, 430 34, 458... 

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

With an omme 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 -methylenedi-aniline 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. 

An homologous series of epoxy resins with constant epoxide equivalent weight and increasing branch concentration displayed increased melt viscosity and weight average molecular weight. 

An important term that is used in formulating epoxy adhesive compositions is epoxy equivalent weight (EEW). This is defined as the weight of resin in grams that contains one equivalent of epoxy. As the resin s molecular weight increases, the EEW will also increase. 

If the resin chains are assumed to be linear with no side branching, and it is further assumed that an epoxy group terminates each end of the molecule, then the epoxide equivalent weight is one-half the average molecular weight of the epoxy resin. 

Similarly, the hydroxyl equivalent weight is the weight of the resin containing one equivalent of hydroxyl group, and it may also be expressed as equivalents per 100 g. Several studies have demonstrated that the hydroxyl content greatly influences the adhesion of the epoxy resin.3,4 These results are best explained by the polar character of the... 

Resin designation Average value of n Melting point, °C Epoxide content, mmol/kg Epoxy equivalent weight Hydroxyl content, mmol/kg... 

The stoichiometric quantity of amine to be used to cure an epoxy resin is easily calculated from the molecular weight of the amine, the number of active hydrogens in the amine, and the epoxy equivalent weight of the resin. This calculation is shown in Table 2.3. 

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