Plastics for low temperatures
Plastics for low temperatures
(OP)
I need to find a plastic that will hold up in a -300 degree F. enviroment. It will not be a constant exposure but a frequent interval of every 12 hours for about 1 minute at a time. I know teflon is good for low temps but it also needs to be a moldable plastic.
Does anybody have any suggestions?
Thanks in advance,
CADShark
Does anybody have any suggestions?
Thanks in advance,
CADShark






RE: Plastics for low temperatures
At -184C I think almost all thermoplastics will go to their brittle phase. Wether or not this generates breaks from thermal shock will depend on design and rate of cooling as well as material choice.
I have never seen data for less than -40 degC, so in the words of Captain Kirk, maybe you are about "to bravely go where no man has gone before".
I will see what I can dig up from my old data.
Maybe other injection mouldable flourocarbons might do the job
Regards
pat
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RE: Plastics for low temperatures
Not true Pat - the ban has been lifted. See
http://www.millenniumchem.com/Products+and+Services/Pro... Good News for users of Cadmium Pigments
Regards,
Peter P
RE: Plastics for low temperatures
Sorry, This should have been in Plastic molds/fabricating engineering.
Regards,
Peter P
RE: Plastics for low temperatures
RE: Plastics for low temperatures
No stress involved, just thermal shock. I have other machined metal parts contained within the plastic but there Coef is higher.
Sealguy,
Forgot about the PFA's and the PCTFE. We need the plastic to be injection moldable.
Has anyone dealt with VESPEL or LUSTRAN? I heard they are good for low temps too.
CADShark
RE: Plastics for low temperatures
Also the plastic will almost certainly go through a second order transition in the range from ambient to -184C, which will cause it to contract somewhat more than the co-efficent of expansion would indicate as it passes through that phase change.
I think sealguy gave you your answer with the injection mouldablr fluorocarbons. Why don't you ask their manufacturers for details.
The figur's you need are co-efficient of expansion and elongation at break, for both properties over the temperature range involved.
Problem is I expect no one has tested for this.
Can you get test plaques or pices of barstock of the canditate materials, drill a hole the appropriate size to allow for mould shrinkage in one of them, heat the plaque, and super cool an insert, place the insert in the hole, allow the whole deal to normalise overnight, then cool the part to -190C
Regards
pat
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RE: Plastics for low temperatures
RE: Plastics for low temperatures
degree celsius. I think this will be cheaper than Teflon, and work better too.
Ståle Eliassen
RE: Plastics for low temperatures
Keep in mind that it has high CTE, and relativly low mechanical strenght.
RE: Plastics for low temperatures
RE: Plastics for low temperatures
RE: Plastics for low temperatures
i know they are good for ski boot parts which need reasonable impact strength at -40 deg C, but thats a long way from -300F
Regards
pat pprimmer@acay.com.au
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