●Good film forming property, without cracking

●Anti-adhesive release effect, even when thinly applied

●Impermeability of PVA film to the organic material used, e.g. styrene

●The PVA film which adhesives to the cast article can be peeled off by hand 

Add 25 ml of N/10 NaOH solution, seal the flask and leave it still for at least 2 hours in room temperature.Add

accurately 25 ml of N/10 H2SO4 solution and titrate back the excess amount of H2SO4 solution present with

N/10 NaOH solution using phenolphthalein as the indicator, until the solution appears in pale pink color.

The volume of N/10 NaOH solution consumed in this titration is a ml. Carry out a blank test separately; the

volume of N/10 NaOH solution consumed in this blank test is b ml.