Re: polyvinyl alcohols (was Re: New Gloy = Bakerex)

Thanks, this is what I was trying to say, but Ryuji said it with
more precision and specificity.
Katharine

On Mar 28, 2006, at 4:43 PM, Ryuji Suzuki wrote:

>> 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 19:10:55 2006