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    There was a problem with this polyketone when Shell first made it.pslc. They can still pack, but not as well as before. But the good part is that the polymer is now a lot tougher and less brittle.pslc.pslc. You see, carbonyl groups are very polar.pslc. To dissolve it you have to use something really weird like hexafluoroisopropanol.ws/macrog/images/ket00. This makes the polyketones very strong, but the down side is that it also makes them very brittle.gif" />

    Ethylene is dirt cheap; it's the monomer for polyethylene.ws/macrog/images/ket06. Let's see what one of these polymers looks like, next to a chain of good ol' polyethylene for comparison:


    For polyketones at a glance, click here!

    I would just love to tell you that many wonderful things are made of polyketones, but I can't.

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      These polyketones have another interesting property. Most high performance polymers are difficult to make, because the chemistry has to be just right for the reactions to work.gif" /> It's not much different. The bad part is that the melting temperature drops to about 220 oC, because the crystals aren't as strong.gif" />
      PolyketonesReference of this text is: http://www. These polar carbonyl groups are attracted to each other, and very strongly at that. This is not to be confused with a carillon, which is a musical instrument with differently pitched bells, which are often controlled with a piano-like keyboard. This is because oxygen is electronegative and draws electrons away from the carbon atom. A car part is no good if it dissolves when you spill gasoline on it.pslc. Ethylene is on the left and carbon monoxide is on the right.pslc. They won't dissolve in much of anything. But that's no problem with polyketones!

    This is all very nice, but really, now, what's the big deal? There are lots of high performance plastics out there.ws/macrog/images/ket08. The reaction is also easy to carry out.

    Here's some models of the monomers if you want to play with them. Propylene reacts just like ethylene does, so we end up with a polymer that looks like this:

    So what's so great about polyketones? Let's find out by taking a look at them. A polyketone is of course a polymer with a ketone group in the backbone chain. This attraction is so strong that while polyethylene melts at a mere 140oC, the polyketone doesn't melt until 255 oC!

    Keep watching this page. But those carbonyls do a lot. You see, these polymers are so new that not much has been made out of them yet.gif" />

    Every now and then you get an extra methyl group attached to one of the ethylene units
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