Determination of Hydrolyzable Chloride Content in Liquid Epoxy Resins

This test method is the determination of the easily hydrolyzable chlorine content of liquid epoxy resins. This is a simple method, hydrolyzable chlorine is saponified with (KOH) potassium hydroxide and titrated with hydrochloric acid (HCl).  

Precautions 

1) Hydrochloric Acid and KOH solutions are corrosive in nature, Toluene is Flammable and their vaporous can be harmful. Handle with proper care.

2) All sample preparations should be done in a well-ventilated area.

2. Apparatus 

a) Magnetic Stirrer

b) Graduated Pipette

c) Graduated Burette

d) Measuring cylinder

e) Erlenmeyer Flasks

f) Analytical Weighing Balance

3. Reagents 

a)  0.1 N Methanolic KOH

b)  0.1 N Hydrochloric Acid (HCl)

c)  Toluene

d)  Phenolphthalein Indicator

4. Procedure

1. Weigh between 6.0 – 8.0 gms of Epoxy Resin in an Erlenmeyer flask.

2. Now add 50 ml of 0.1 N methanolic KOH, then add 15 ml of toluene.

3. Slight warm and stir to mix.

4. Allow to cool at room temperature.

5. Now add 3 drops of Phenolphthalein indicator and titrate with 0.1 N HCl. (Endpoint is taken when 1 drop changes the solution from pink to colorless.)

6) Make a BLANK determination on the reagents following the same procedure without RESIN SAMPLE.

TESTING METHOD  OF HYDROLYZABLE CHLORIDE CONTENT OF LIQUID EPOXY RESINS

5.  CALCULATIONS

                                         H = (V-B) N x 3.55

                                                     W

Where

H = Weight (%) of Hydrolysable chloride,

B = ml of HCl required for the titration of BLANK

V = ml of HCl required for the titration of RESIN SAMPLE

N = Normality of the HCl solution

cc. = FACTOR (grams of chloride per mill equivalent multiplied by the %age factor of  100

W = RESIN SAMPLE weight

Liquid Epoxy Resins Specification

Epoxy Equivalent Weight:  185 - 194 g/eq

Color (APHA): 0 - 100 

Viscosity @25 C:  11000 - 14000 cps

 hydrolyzable chlorine: 0.0 -0.05

Testing methods epoxy equivalent weight and epoxy value

BANTI SINGH

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