How to detect the epoxy value of epoxy soybean oil
Epoxy value is an important performance index of epoxy resins, which can be used to identify the quality of epoxy resins or to calculate the dosage of hardener.
Determination of Epoxy Value: Hydrochloric acid-acetone method, hydrochloric acid-acetone method is one of the most common methods for determination of epoxy value. The specific actions are as follows:
(1) Preparation of hydrochloric acid-acetone solution: Take 1 unit volume of Hydrochloric acid (AR), add to 40 unit volume of Acetone (AR), shake and then put the corresponding label in the reagent bottle, stamped.
(2) Preparation of sodium hydroxide ethanol solution: accurately weighing about 0.4g of NaOH, mixed with a small amount of anhydrous ethanol added to the 100mL capacity of the bottle, and then add ethanol to the tick mark Line, stamped with the corresponding labeling of the reagent bottle, stamped to be used to calculate the NaOH of the amount of material concentration (mol).
(3) Take a cone-shaped bottle containing a reaction mixture of known quality, add a 25mL hydrochloric acid-acetone solution with a 25mL liquid tube, and seal and shake to dissolve the resin completely. After 1h, add 3 drops of Phenolphthalein reagent, titration to the solution into pink with NaOH ethanol solution, and not fade in 30s. At the same time, two blank titration is carried out according to the above conditions.
4) Calculation of epoxy value:
E= (V1-V2) xc÷10m
Type, E: Epoxy value;
V1: Titration of the average volume of NaOH ethanol solution consumed by two blank samples, ML;
V2: The volume of NaOH ethanol solution consumed by titration of a known mass reaction mixture, mL;
M: The quality of the reaction mixture, G.