To read about F's and my London trip, start here and click "newer post" to continue the story.

Thursday, February 23, 2006

R and I attended another American Chemical Society meeting and talk tonight. This talk was about polymers made from lignin which is extracted from wood pulp. Our speaker said that this is very green, because wood is renewable, and that it will reduce our dependency on petrochemicals. However, he talked a lot about styrene. During the Q&A I asked if their styrene was derived from petroleum or if they were recycling it. He said that they are using petrochemically-derived styrene but that you can produce acetylene (C2H2) from lignin and make other chemicals; specifically, you can hit it with benzene and make styrene. Hello, benzene is a petrochemical too. I suppose the other chemicals he was talking about - little bitty hydrocarbons like methane and propene and so forth - could be produced in fermentation vats, but I'm not seeing benzene being produced that way.

Oh well. It was an interesting talk. He showed us a diagram of an extrusion device consisting of a screw being turned by some sort of motor. The stuff being extruded is introduced between the threads at the motor end of the screw and is forced along its length as the screw turns, until it is pushed through a dye at the end to form whatever shape you want. You can start with deep threads and make them progressively shallower if you want to compress your material before you extrude it.

This reminded both me and R of a time when F was quite small. She had some blocks with holes in them that you could drop marbles through, and messing around as kids will, she forced play-dough through one of the blocks. "Look, Mommy, I'm making a worm!" she said. I admired her worm, and then I told her that that process was called "extrusion" and she could say that she was "extruding" a worm. Then I suggested that she go and tell her daddy that she was extruding a worm. Which she did. R's shock and horror overtook him before he asked could himself how a very small child would know that word and he shouted, "From where?" We've laughed about that ever since, but I'm secretly glad that R is not as mischievous as I am. I don't think I would like it if he was.

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