From: Alan \"Uncle Al\" Schwartz <email@example.com>
Subject: Re: Questions on Soft Clear PVC & Plastics
Date: 24 Feb 1996 23:07:57 GMT
Poly(vinyl chloride) neat is a clear, glass-like resin.
Finely powdered PVC resin in, for instance di-octyl phthalate, is fairly
stable at room temp. If you heat it up in a mold the ester dissolves in
the polymer and the whole mass fuses into a soft (depends upon how much
and what plasctizer) whole. Consider Tygon tubing or shower curtains.
Plasticized PVC has wonderful short-term physical properties, it is
biologically inert, cheap to manufacture, and valued-added to sell.
The entire planet is contaminated with phthalate plasticisers slowly
blooming from untold gigatons of plastized PVC, Naugahyde and whatnot.
The oily stuff which deposits inside your auto's windshield is
plasticizer from your plastic upholstery.
Now comes the fun part. Oddly enough, just about every class of chemical
which strongly triggers a gas chromatograph's electron capture detector
has many members which are potent mutagens by the Ames test, and which
show other inimical chronic biological effects. Phthalates make EC
detectors shoot off-scale, but appear to be harmless - maybe. They also
resist environmental degradation and concentrate in body fat, amplifying
up the food chain.
PVC itself is a real nuisance at disposal time. Burning PVC relases vast
amounts of HCl, which corrodes incinerators. PVC and PET are hard to
distinguish. Only a few ppm of PVC in recycled PET turns nice white PET
insulation fluff into black crud.
Alan "Uncle Al" Schwartz
UncleAl0@ix.netcom.com ("zero" before "@")
"Quis custodiet ipsos custodes?" The Net!