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Colored thermoplastic is catalin, huh!?

Started by BDM, March 02, 2009, 01:49:01 PM

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BDM

--Brian--

St Clair Shores, MI

benhutcherson

You all probably know this, but it's probably worth mentioning that Bakelite and Catalin are one in the same. They're both brand names for phenol formaldehyde resin. Catalin, I believe, always uses wood flour for the filler.

So, in any case, the reviewer is definitely way off.

bingster

Quote from: benhutcherson on March 02, 2009, 02:04:38 PMCatalin, I believe, always uses wood flour for the filler.
Other way around.  Bakelite uses wood flour, while catalin uses very little, leaving only the translucent resin.
= DARRIN =



BDM

If I'm not mistaken, it's the flour that "binds" the resin, making it less brittle, and less prone to shrinking/cracking.
--Brian--

St Clair Shores, MI

Dan/Panther

#4
I found the following article a couple years back, and was basically shocked at what it said.
To think that catalin, an very fragile substance and Bakelite almost impervious to damage from other than breakage, are one and the same.
I just find it hard to believe that a little wood flour is the difference.
It must be the powedered wood cellulous, reacts with the resins and hardens everthing up in regular bakelite, in effect changing the chemical properties while it's still in a liquid state. Otherwise it just does not seem even remotely the same.
Just the nature of wood itself tells us, that something strange is going on inside it, wood can last for centuries if properly cared for. I think, that "strangeness" fuses with the resins and makes it bakelite as we know it. I'm not a chemist, but something has to change between the two.
I guess what I'm trying to say in a round about wasy, is by adding the wood flour, the resin is chemically altered into a new resin, that we know as Bakelite, really just foundationally the same, like water, and ice. Wheat flour being the cold, that is added to water to make it harder ice.
Also Catalin is a cast material, where bakelite is pressure molded , maybe the heat and pressure causes a change ?
D/P

http://www.helium.com/items/244855-bakelite-vs-fakelite-how-to-tell-if-your-vintage-jewelry-is-genuine

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson

bingster

It could be that the heat and pressure causes some sort of chemical change, I don't know enough to even guess.  I do know that colored bakelite does shrink.  I have a small bakelite trinket box that has a black box with a red lid, and the lid has shrunk slightly.  I don't know if the red part has less filler than the black, or what, but it's as light-proof as the black part.
= DARRIN =



benhutcherson

My guess would be that the phenol formaldehyde polymer physically binds to pores in the wood flour, and the lignin helps to provide mechanical support for the polymer.

If you look at the structure of the phenol formaldehyde polymer, it is very three dimensional, and can extend indefinitely in all directions. That sort of structure is very stiff, but also very brittle.

Another example would be iron vs. steel. Cast iron is brittle, while only a small amount of carbon added to iron makes it very sturdy and durable.

I don't think that filler material(which isn't always wood flour) really is causing any sort of chemical change in the polymer. The heat and pressure associated with molding bakelite would cause the polymerization to happen faster, but it wouldn't necessarily change the structure of the polymer.

All of the above is just my educated guess, having spent a small amount of time studying polymer chemistry(and a large amount of time studying organic chemistry). No guarantees that it's right.

I'll have to see if I can bribe a friend with access to an electron microscope to take some electron micrographs of bakelite vs. catalin, which would tell a whole lot about how they're different.