PVC is THE worst, or THE best plastic, depending on how you look at it.
It's worst features are it's lifecycle contribution to toxic chemical waste, and toxicity to workers (now much better than it was in the 1960's due to stringent laws and practices). It is uniquely among plastics made with toxic Chlorine, and the Vinyl Chloride precursor is one of the most toxic gasses there is.
Fortunately Vinyl Chloride isn't one of the usual breakdown products of PVC when it burns. But what is, Dioxins, are still very toxic, low level exposures won't necessarily kill you right away so much as giving you cancer later.
So, don't burn the stuff. Fortunately, and on the good side, PVC doesn't burn easily, with combustion point as high as 450 degrees Celsius or 842 degrees Fahrenheit. That's way way above the burning point of most other plastics, wood, paper, etc. At that point, you're melting lots of metals, in fact I solder at a mere 720 degrees F. When I solder vinyl coated wire, the vinyl sometimes melts but rarely burns (mere singing). I've never seen it catch fire.
Unfortunately, some does get burned anyway, in the inferno of building fires, auto and plane crashes, etc. And municipal incinerators.
PVC is actually very special among plastics, being amorphous in nature (made possible by the highly polar Chlorine atom), highly viscous when melted and very easily molded into complex and detailed shapes (LP records have a micro grove that requires precision so great it's a challenge to read optically…pressed on a mechanical stamper…no other plastic can do anything like that, it's almost a miracle).
Here's a great puff piece on PVC where I learned about the wonderfulness of PVC.
I still prefer other plastics, such as polyethylene, when possible, and especially for wire dielectrics.
With Urethanes, the breakdown product in fire, which is easier to stimulate, is cyanide gas, also known as Zyklon B. For immediate exposure, I am thinking that must be worse than the Dioxins from burning PVC. Urethane foam generally contains a fire retardant--so I'm not sure how the mixture compares to PVC products, despite PVC's inherent superior fire resistance.
It's worst features are it's lifecycle contribution to toxic chemical waste, and toxicity to workers (now much better than it was in the 1960's due to stringent laws and practices). It is uniquely among plastics made with toxic Chlorine, and the Vinyl Chloride precursor is one of the most toxic gasses there is.
Fortunately Vinyl Chloride isn't one of the usual breakdown products of PVC when it burns. But what is, Dioxins, are still very toxic, low level exposures won't necessarily kill you right away so much as giving you cancer later.
So, don't burn the stuff. Fortunately, and on the good side, PVC doesn't burn easily, with combustion point as high as 450 degrees Celsius or 842 degrees Fahrenheit. That's way way above the burning point of most other plastics, wood, paper, etc. At that point, you're melting lots of metals, in fact I solder at a mere 720 degrees F. When I solder vinyl coated wire, the vinyl sometimes melts but rarely burns (mere singing). I've never seen it catch fire.
Unfortunately, some does get burned anyway, in the inferno of building fires, auto and plane crashes, etc. And municipal incinerators.
PVC is actually very special among plastics, being amorphous in nature (made possible by the highly polar Chlorine atom), highly viscous when melted and very easily molded into complex and detailed shapes (LP records have a micro grove that requires precision so great it's a challenge to read optically…pressed on a mechanical stamper…no other plastic can do anything like that, it's almost a miracle).
Here's a great puff piece on PVC where I learned about the wonderfulness of PVC.
I still prefer other plastics, such as polyethylene, when possible, and especially for wire dielectrics.
With Urethanes, the breakdown product in fire, which is easier to stimulate, is cyanide gas, also known as Zyklon B. For immediate exposure, I am thinking that must be worse than the Dioxins from burning PVC. Urethane foam generally contains a fire retardant--so I'm not sure how the mixture compares to PVC products, despite PVC's inherent superior fire resistance.
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