[net.consumers] Lifetime of foam products

wmartin@brl-tgr.ARPA (Will Martin ) (11/15/84)

Lately, I have noticed various plastic foam pieces deteriorating or
disintegrating. This reminded me that I had also seen such an effect
in the past; the classic example is the foam mat on the old AR turntable.
I have even seen references in print to the effect that those foam mats
all disintegrated. I've seen foam pieces in such places as the battery
compartment of a portable radio just turn to crumbles. 

Does anyone know what is going on here? I don't know what type of plastic
these foams are made from; could some chemist on the net discuss this?
Does this stuff have an actual "lifetime", and it will disintegrate after
"n" years from being formed, no matter how carefully it is treated or stored?
Or is this due to environmental effects, like temperature changes and 
airborne contaminants? 

I'm worried that many consumer products have pieces of foam built in as
cushioning or to take advantage of the foam's springiness, like on
a battery-compartment door. Were all these uses of foam done with no
knowledge of the fact that the foam will deteriorate? Or will some last
much longer than other types? How can we determine what type we have,
and what should be used to replace it?

Will Martin

USENET: seismo!brl-bmd!wmartin     or   ARPA/MILNET: wmartin@almsa-1.ARPA

paulb@hcrvax.UUCP (Paul Bonneau) (11/18/84)

[Out vile jelly!]

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keithd@cadovax.UUCP (Keith Doyle) (11/20/84)

>Lately, I have noticed various plastic foam pieces deteriorating or
>disintegrating...... 

>Does anyone know what is going on here?....

>Will Martin

I've wondered that myself.  I've noticed that the black 'static' foam
used to store static sensitive I.C.'s turns to a kind of sticky-black-
powder-goo after a few years.  I found some of it at the bottom of a
parts junk box and it took me a while to figure out what it was.  Also,
I have a pair of Sennheiser headphones, the standard studio type with the
yellow foam ear-pieces, and the foam has recently fallen apart.  Seems as
if there is some built in obsolescence, or something.  Couch and mattress
foam seems to get powdery in time too, I've noticed.  Time for some new
hi-tech foam products I guess.

Keith Doyle
{ucbvax,ihnp4,decvax}!trwrb!cadovax!keithd
"You'll PAY to know what you REALLY think!"

david@bragvax.UUCP (David DiGiacomo) (11/27/84)

In article <5783@brl-tgr.ARPA> wmartin@brl-tgr.ARPA (Will Martin ) writes:
>Lately, I have noticed various plastic foam pieces deteriorating or
>disintegrating.

Ultraviolet radiation and ozone depolymerize plastics.  For best
results, keep windows closed and fluorescent lamps off while plastic
products are in use.  Don't use plastics near brush-type electric motors
or welders.  Never put plastics in an EPROM eraser.

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