"Bruce Sterling - Superglue (2)" - читать интересную книгу автора (Sterling Bruce)

CN
/
CH2=C
\
COOR

The R is a variable (an "alkyl group") which slightly changes
the character of the molecule; cyanoacrylate is commercially
available in ethyl, methyl, isopropyl, allyl, butyl, isobutyl,
methoxyethyl, and ethoxyethyl cyanoacrylate esters. These
chemical variants have slightly different setting properties and
degrees of gooiness.

After setting or "ionic polymerization," however, Superglue
looks something like this:

CN CN CN
| | |
- CH2C -(CH2C)-(CH2C)- (etc. etc. etc)
| | |
COOR COOR COOR

The single cyanoacrylate "monomer" joins up like a series of
plastic popper-beads, becoming a long chain. Within the thickening
liquid glue, these growing chains whip about through Brownian
motion, a process technically known as "reptation," named after the
crawling of snakes. As the reptating molecules thrash, then wriggle,
then finally merely twitch, the once- thin and viscous liquid becomes
a tough mass of fossilized, interpenetrating plastic molecular
spaghetti.

And it is strong. Even pure cyanoacrylate can lift a ton with a
single square-inch bond, and one advanced elastomer-modified '80s
mix, "Black Max" from Loctite Corporation, can go up to 3,100 pounds.

file:///C|/Documents%20and%20Settings/harry%20kruiswijk...20documenten/spaar/Bruce%20Sterling%20-%20Superglue.txt (5 of 7)20-2-2006 23:37:26
 file:///C|/Documents%20and%20Settings/harry%20kruiswijk/Mijn%20documenten/spaar/Bruce%20Sterling%20-%20Superglue.txt

This is enough strength to rip the surface right off most substrates.
Unless it's made of chrome steel, the object you're gluing will likely
give up the ghost well before a properly anchored layer of Superglue
will.

Superglue quickly found industrial uses in automotive trim,
phonograph needle cartridges, video cassettes, transformer
laminations, circuit boards, and sporting goods. But early superglues
had definite drawbacks. The stuff dispersed so easily that it
sometimes precipitated as vapor, forming a white film on surfaces
where it wasn't needed; this is known as "blooming." Though