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PolyEtherKetoneEtherKetoneKetone (PEKEKK) hydrolysis 1
- Thread starter kevlar49
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Compositepro
Chemical
I believe it is very good, but all I can say is I'm somewhat familiar with the polymer and I've never heard of any problems in that area. PEEK has very good chemical resistance.
EdStainless
Materials
I would be more concerned about the filler than the resin. We used PEEK, PEK, PAK in water at 550F for long periods with no degradation. We could break down glass fiber under those conditions.
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Plymouth Tube
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Plymouth Tube
- Thread starter
- #5
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- #7
Sorry wasn't clear. We are maintaining elevated pressure such that the fluid will remain water. There is no replenishing source of air contamination so CO2 will be limited in quantity. Question was directed to EdStainless's comment about glass breaking down.
Does anyone know of a specific database where I might find hydrolysis data?
Does anyone know of a specific database where I might find hydrolysis data?
btrueblood
Mechanical
Yes, from experience at lower temperatures, I would expect glass fiber to corrode/break down in 302 F water. I've never found a definitive data base for hydrolysis of polymers. If you find one, please come back here and post a link!
patprimmer
New member
There was a lot of work done on polymers for automotive radiator header tanks where they needed a material for extended life in a system at near boil at 15psi the coolant being water or a water/glycol mix.
They ended up with a pretty special grade of glass fibre reinforced nylon 6.6.
They had to use special hydrolysis stabilisers for the polymer as nylons are normally prone to hydrolysis, but they also needed a very special grade of glass fibre. It definitely had a special hydrolysis resistant coating to assist in bonding to the polymer, but I think the actual glass was also a special grade.
How this applies to the OP I'm not quite sure other that to alert him that there is more than one source for potential problems and answers might not be generic.
The raw material manufacturer should be the best source of real data with qualifiers about certain grades.
Regards
Pat
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They ended up with a pretty special grade of glass fibre reinforced nylon 6.6.
They had to use special hydrolysis stabilisers for the polymer as nylons are normally prone to hydrolysis, but they also needed a very special grade of glass fibre. It definitely had a special hydrolysis resistant coating to assist in bonding to the polymer, but I think the actual glass was also a special grade.
How this applies to the OP I'm not quite sure other that to alert him that there is more than one source for potential problems and answers might not be generic.
The raw material manufacturer should be the best source of real data with qualifiers about certain grades.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
EdStainless
Materials
Sorry, I'll add that we were at high pressures, very much liquid water at 550F.
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Plymouth Tube
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Plymouth Tube
btrueblood
Mechanical
Pat,
Just curious, having seen a few plastic radiator headers. They look awfully smooth, i.e. I don't see much glass fiber showing on the surface. Is it possible these things get an over-mold, or some kind of secondary (post molding) dip treatment to provide a further barrier between the glass fiber and the liquid?
Just curious, having seen a few plastic radiator headers. They look awfully smooth, i.e. I don't see much glass fiber showing on the surface. Is it possible these things get an over-mold, or some kind of secondary (post molding) dip treatment to provide a further barrier between the glass fiber and the liquid?
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patprimmer
New member
No. They are typically 33 to 35% GF nylon 6.6.
The gloss comes from correct moulding techniques of quite hot melt, very large gate, extremely fast injection speed, a very hot mould and lots of hold up time and pressure.
So called glassy surface is typically really silver streaks caused by glass suck back from the surface as the matrix shrinks and the molten sub surface flows relative to the rubbery surface. The glass fibers are then pulled from the surface leaving little voids that show up silvery in appearance and look like glass fibres.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
The gloss comes from correct moulding techniques of quite hot melt, very large gate, extremely fast injection speed, a very hot mould and lots of hold up time and pressure.
So called glassy surface is typically really silver streaks caused by glass suck back from the surface as the matrix shrinks and the molten sub surface flows relative to the rubbery surface. The glass fibers are then pulled from the surface leaving little voids that show up silvery in appearance and look like glass fibres.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
for site rules
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