> In a message dated 28/3/06 4:45:46 pm, kthayer@pacifier.com writes:
> > (get some PVA of whatever kind (although the
> > degree of hydrolysis should be high regardless) some glycerine, some
> > water; mix them together in proportions of your choosing until it
> > seems about right)-
Degree of hydrolysis varies a lot. Higher degree of hydrolysis would
increase adhesion to hydrophilic surfaces, but not hydrophobic; the
reverse for low hydrolysis PVA. Higer hydrolysis would result in
increased tensile strength, and lower, increased flexibility. It is
probably easiest to test the degree of hydrolysis by testing for water
sensitivity or emulsifying power.
Incidentally, the different degree of polymerization would result in
different viscosity, as well as water sensitivity, adhesion,
emulsifying power, etc. It's best to determine viscosity first.
From: TERRYAKING@aol.com
Subject: Re: New Gloy = Bakerex
Date: Tue, 28 Mar 2006 10:52:01 -0500 (EST)
> Viscocity is sufficiently related to specific gravity for our purposes.
This is not true. SG of pure PVA is about 1.27 to 1.31 and is related
to degree of crystallinity.
Like I said in earlier posts, there are several important variables in
variations of PVA and water content is not the only difference in
proprietary products. If any of these is important to your
application, trying to figure out proprietary products is waste of
time. Just buy one that comes with information on the exact
composition from the original chemical manufacturer.
Received on Tue Mar 28 18:45:06 2006
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