Re: RE- Re: Polyethylene

Subject:  Re: RE- Re: Polyethylene
  Date:   Sun, 15 Jun 1997 22:38:58 +0500
  From:  "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
    To:   Tesla List <tesla-at-pupman-dot-com>

On Sun, 15 Jun 1997 17:48:22 -0400 Daryl P. Dacko
<mycrump-at-cris-dot-com> wrote;

> Polyethylene is a thermoplastic, and will melt, and it is possible to 
> recycle it.

This is the impression I have always had! Polyethylene is one of 
those plastics that are BOTH thermoplastics AND thermo-setting 
plastic. Bakalite by contrast is thermo-setting but it is NOT a

> Polyethylene and polyproplyene don't really 'melt', they (above a 
> certain critical temperature) just get softer and softer. Usually 
> you can't get them hot enough to flow by themselves without a fair
> amount of degradation of their propertys.
> The crosslinking you heard about is used to stiffen the polymer and
> give it propertys that it wouldn't have otherwise. If it were carryed
> out too far, the polymer wouldn't melt, true enought, just like 
> thermoset plastics, but just a little helps... 

If memory serves me there is an irradiated form of polyethylene that 
is not a thermoplastic.

> A way you =could= recycle it would be to use what's called compression
> moulding. You make a frame the same thickness as the sheet of plastic
> you want to make, lets say 18 inches square and 90 mills thick. You
> cut out a hole in the center to leave a border arount the outside...

Your suggested procedure sounds good! With a little experimentation 
it just might work! Thanks for the info!!!


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