Tabun
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Polymerization-Kevlar
Can somebody explain me how Kevlar is made?I googled it and I found the reaction and what's happening but I already knew that.Can somebody tell me the
conditions for the reaction and some other important things about it?To make sure you understand what I'm saying here I say that it's like I found
that TNG can be made with glycerin and nitric acid but I didn't found the temperature for example,or anything about the sulfuric acid.
And,an off-topic question so I won't start another one : can somebody give me a book about substances like benzene,toluene,xylene...etc which contains
their reaction with different substances.Again,I want the conditions for the reactions like temperature,catalysts,how they influence the isomers
formation,purification...etc.
[Edited on 1-5-2015 by Tabun]
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Steam
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This is the polymerization of an amine and an acyl chloride. Acyl chlorides are fairly reactive with primary amines and thus this reaction will
probably happen in fairly light conditions. When this reaction progresses HCl will be given off. This is similar to a condensation reaction where H2O
is released. From what a quick google search showed me, pyridine is often used as a solvent for this reaction to scavenge for free hydrogen, however I
do not know if pyridine is necessary.
Once the larger monomer is formed, a simple connection reaction takes place. This link here might help. http://chemistry2.csudh.edu/rpendarvis/carboxder.html
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Tabun
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Quote: Originally posted by Steam  | This is the polymerization of an amine and an acyl chloride. Acyl chlorides are fairly reactive with primary amines and thus this reaction will
probably happen in fairly light conditions. When this reaction progresses HCl will be given off. This is similar to a condensation reaction where H2O
is released. From what a quick google search showed me, pyridine is often used as a solvent for this reaction to scavenge for free hydrogen, however I
do not know if pyridine is necessary.
Once the larger monomer is formed, a simple connection reaction takes place. This link here might help. http://chemistry2.csudh.edu/rpendarvis/carboxder.html
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Didn't find that site...and I've been looking for a while.I also found this patent on polyamides:
http://www.google.com/patents/US2831834
...found another thing
"The reaction occurs under anhydrous conditions at temperatures between -15o C and 30o C [4]. During the reaction hydrochloric acid is produced as a
product of the two monomer molecules. This acid is may cause significant corrosion problems in processing equipment such as the spinneret. Therefore
it is necessary to add a base to the solution to neutralize the acid [4]. The preferred bases are lithium and calcium salts. The solution of the two
monomers is stirred continuously for two to twenty four hours as the polymer forms [4].
After the stirring is complete, the solution has turned into a viscous, gel-like mass. In addition to the desired compounds there may be some
insoluble salts formed [4]. It is necessary to remove these salts before the material is pressed or spun. After these impurities are removed the fiber
may be concentrated under vacuum to produce the fluid desired for spinning. To isolate the poly(p-benzamide) the mixture is combined with water in a
suitable blender and then is converted to a powder. This powder is washed with water and alcohol and is dried overnight in a vacuum oven at about
60o-70o C [4]. The Kevlar fibers are all that is left and they are ready to be spun.
Kevlar yarn is spun in a process known as wet spinning. In this process, a solution of 100% anhydrous sulfuric acid and Kevlar fibers are pushed,
under pressure, through small holes [4]. The device that the dissolved polymer is passed through is called a spinneret. As the molecules pass through
the tiny holes in the spinneret they are all aligned in a uniform position [5]. As they leave the spinneret, the newly formed yarn is cooled and
solidified by cold water. Then the fiber is heated slightly, hardening it, and is spun up on a spool [6]. This is the final product of the Kevlar
production process and now the yarn is ready to be sold.
"
[Edited on 1-5-2015 by Tabun]
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IrC
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A few more patents which may be useful to study:
http://www.freepatentsonline.com/2071250.html
http://www.freepatentsonline.com/2130523.html
http://www.freepatentsonline.com/2374069.html
http://www.freepatentsonline.com/2462430.html
http://www.freepatentsonline.com/2327116.html
http://www.freepatentsonline.com/2284637.html
http://www.freepatentsonline.com/2333914.html
http://www.freepatentsonline.com/2451672.html
"Science is the belief in the ignorance of the experts" Richard Feynman
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