Posted by Bengt Blomberg on March 06, 2002 at 17:26:31:
In Reply to: acid posted by enrique on March 06, 2002 at 11:46:39:
: How is possible that part of osmosis is done by an acid? The chemycal IndustrY use fiberglass tanks.
: Sorry for my English
it is the quesstion of a specific acid e.g. phthallic acid which is one of the original ingredients in when formulating the polyester resin.
Now, it is small uncured polyester enclosures in the cured laminate which can be hydrolysed only and here no acid is involved. Therefore normally the hydrolysis should stop when all of the enclosures are hydrolysed.
However when the hydrolysis splits up the polyester molecules, phthallic acid and phthallic salts are formed.
Besides the uncured enclosures the cured resin contains more or less not completely cured polyester chains with one or more phthallic molecules at the ends. When free phthallic molecules comes into contact with such a so called "dangling chain" the curing links become totally broken and new enclosures of uncured polyester and styrene forms. If a few water molecules are available the hydrolysis then starts again. This is the reason for the many recurrensies by normal "dry and shield" repairs.
Regarding chemical tanks they mostly use epoxy resin for the laminate or has an epoxy coating on the inside and I do not think anyone would submerge such tanks in water!
If you have more questions you are welcome to e-mail me in Spanish which I can read and understand but not write well enough.
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