ME418 Lecture 5 PVC - Polyvinylchloride

ME418 Lecture 5 PVC - Polyvinylchloride - Called Cancer...

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5: PVC - Polyvinylchloride Tuesday, February 19, 2008 First discovered by Baron von Liebig in 1835 Acetylene + HCl in sunlight with mineral deposits Plastic material that did not appear to melt o Turned yellow, then brown, then decayed and released HCl Waldo Semon replaced shower curtains (cloth with polyisoprene - vulcanized rubber) o Mixed PVC with a plasticizer (Dioctyl phthalate - DOP) o Plasticizer: Low MW material / additive Lowers melting point by separating molecules to improve flow Allows hard materials to be soft at room temperature Shoe soles, window frames, car seats  Directly influences process ability Lowers processing temperature less than degradation temperature Incredible Material (elastic rubber to rigid plastic) but dark sides exist o Vinyl chloride monomer (well-known carcinogen) 90% of worlds PVC produced between New Orleans and Baton Rouge
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Unformatted text preview: Called Cancer Alley o Stabilizers • Cheapest are lead products • Low regulation from imported products o Plasticizers • Inexpensive can be dangerous / carcinogenic • Some emulate estrogen (interfere with sexual development) o Burning PVC • Chlorine is ~60% of the mass • Turns into CO 2 and HCl • Disposal: Incineration / Landfills o US: 500 million pounds in 2001 o Contributes 35-66% of chlorine into waste stream o Dioxin Releases • Municipal Incinerators - 55% of dioxin releases • Household burning - 20% of dioxin releases o 2-4billion pounds sent to US landfills in 2001 o Additives seep out into surrounding environment, soften adjacent plastics o PVC used as a landfill liner • Some companies working on phasing out PVC...
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