Thursday, November 18, 2010

spinning vinyl

My collection of vinyl records still sits in my living room under a coffee table, though I haven't played them in years.  I have a turntable and a component system that is old enough to play them but it's just too much work, and a lot of the music I have is not interesting to me anymore.

I expect I would encounter some trouble if I tried to play them anyhow, since many of them were made when records were stamped on thin vinyl, which would warp over time if not occasionally rotated.  Letting them sit on one side for years could have caused some major problems.

I spent a lot of time as an adolescent listening to records, so just talking about them gets me feeling a little nostalgic. 

LP (long play) records like this are called vinyl because they are made from polyvinyl chloride.  Vinyl chloride is CH2CHCl, an alkene with a chlorine attached to the sp2-hybridized carbon, aka the vinyl position.  Addition reactions can be used to produce polymers which often end up bearing the names of their raw materials, or suggestions of what those raw materials are:  polyvinyl chloride (PVC), polyethylene (HDPE and LDPE), and polystyrene (PS) are all made from alkenes, through addition reactions that cause them to polymerize.

Organic students may recognize, if they think of it, that after forming a carbocation in an addition reaction one could imagine another molecule of the original alkene behaving as a nucleophile...the double bond itself is rich in electron density.  This is the underlying principle of the addition polymerization reactions that allow us to make all these different plastics.

Wikipedia has relatively informative articles on LP records, and on vinyl chloride.  PVC is not very environmentally friendly if you consider the problems that come along with handling the vinyl chloride monomer which it is made of, though some have argued it is very environmentally friendly precisely because it lasts so long--and often is used in applications to replace wood, or other plastics with shorter lifespans.

A few years ago a great (but admittedly biased) documentary about PVC was put out by Bullfrog Films.  You can watch the trailer here, and it's in our College Library.  It's worth your time and presents the serious problems associated with PVC with great humor.  And you know what's funny and ironic?  The videocasette that the film is on is probably made guessed it:  PVC.

No comments: