-Mario- -Mario-:
Regina Regina:
I think it's a pile of crap too. What's the difference in plastic for a Nalgene water bottle and what you buy in the store? They're both polycarbonate plastic.
All plastic bottle... of any kind should not be refilled.... they release too much harmful chemicals.
If leaching chemicals were such a problem, then new bottles are even more so. Plastic will off-gas non-polymerized chemicals more when it's new, less after it's older. That's because the chemicals that have not combined to form plastic have left, either by off-gassing or leaching. Furthermore, new bottles will sit in a warehouse, transport truck, and store shelves much longer than water you put in yourself. So there will be much more chemicals in a new bottle than a refilled one.
As for bacteria, it's called washing. If you don't wash a plate or cup or fork or spoon, then you could get bacteria. There won't be any more bacteria in a washed water bottle than any other washed dishes. And you know what bacteria will be there, it's stuff from your own kitchen. If you're worried about scratches, just look at the bottle. If it becomes milky white with scratches then don't use it. If it's still clear then it doesn't have scratches. Simple.
Polycarbonate has the advantage it's much harder and stronger than PET. There will be fewer scratches, hence much less chance of that bacteria boogieman. Besides, clear polycarbonate also shows scratches, again if it's so scratched you can't see through it then don't use it; if it's still clear then it isn't scratched so use it.
So back to chemical residue. The detailed chemical steps to make polycarbonate are:
acetone + phenol + hydrochloric acid -> bisphenol-A
bisophenol-A + sodium hydroxide -> sodium salt of bisophenol-A
carbon monoxide + chlorine -> phosgene
sodium salt of bisophenol-A + phosgene -> polycarbonate
Those who are sharp will notice what bisphenol-A reacts with: phosgene. That's a poison gas used in World War 1. If there's any of that in the plastic it would be toxic. In fact breathing it is poisonous, so it couldn't be used for hockey helmet visors either. But it doesn't off-gas because the manufacturing process ensures all the phosgene gas is reacted to form plastic. There isn't anything to leach out.
If you want to know other plastics, let's start with PET:
naphthalene is an olefin, a large hydrocarbon: C10H8
terebinth is refined terpentine
naphthalene + terebinth -> terephthalic acid
terephthalic acid + glycol -> Polyethylene Terephthalate (PET)
High Density PolyEthylene (HDPE):
ethylene + ½ O2 -> ethylene oxide
ethylene oxide + water -> ethylene glycol over a silver catalyst @ 250°C
polymerize using a catalyst
Acrylic technically known as Polymethyl Methacrylate (PMMA):
ethylene -> propylene
propylene -> glycerol
glycerol -> acrolein
acrolein + O2 -> acrylic acid
polymerization of acrylic acid
So if you're looking for the ideal material to use for food, use acrylic. It's hard like polycarbonate, not soft and squishy like PET. Don't use polystyrene, it yellows rapidly from UV light.
A number of plastics have nasty chemical intermediates. For example, nylon uses hydrogen cyanide in an early step. Melamine uses ammonia and urea. PVC or vinyl uses chlorine gas. The pink binder used to hold fibres together for fibreglass "pink" insulation is phenolformaldehyde, made from phenol and formaldehyde. The pink stuff is a lot less toxic than the yellow stuff they used to use for fibreglass, that was ureaformaldehyde. Yup, if you have yellow fibreglass in your walls you do have a little ureaformaldehyde, it's a tiny amount compared to foam insulation (UFFI) but there is a little there.
The one plastic that does leach significantly is ABS. To put it simply, that is a co-polymer of butadiene rubber (BR) with styrene. ABS stands for Acrylonitrile Butadiene Styrene. It's strong and resists stomach acid (puke) so is useful for drain pipes, but don't use it for drinking water because it does leach chemicals.
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