I happened to be looking for a particular cord connector in a box of ‘stuff’. Said stuff comprised everything from cords, odd paperwork, broken sunnies, superfluous bits of vacuum cleaner attachments and misc odds and ends. Y’know, a box of STUFF.
And I came across a piece of phone line (wall jack one end, phone connector the other) that had MELTED into another piece of plastic (a dust jacket fom an old street directory). :eek:
About three weeks ago there was a smell of burning in the room where box lives (my office) and I put it down to an electrical problem in the light fitting (still waiting for an electrician to arrive btw)…however I suspect now that the smell may have emanated from the box of stuff as the plastic started to melt away.
There is no direct heat source that would explain the melting, nor did the melt site have any contact with other chemicals. There WERE some old tubes of facial moisturiser at the bottom of the box, but not in direct contact with the melted bits. Nothing else in the box of stuff is affected in any way.
Help me out here…because it is bloody scary that something so innocuous could be potentially so bloody dangerous.
Sure, I figured it must have been something like that, but if two plastics can have that sort of effect it’s downright dangerous to store such things together…which is exactly what 99% of the population do.
What exactly would this chemical reaction have been, and why aren’t such potential dangers brought to the attention of ordinary folk like me?
I would say unrelated, and don’t cancel the electrician.
While they look melted, they probably flowed together, and didn’t get hot.
What seems more likely is that the plasticisers leaking from the dust jacket caused the breakdown of the phone line insulation - straight chemical incompatibility. It could also be volatile chemicals from the moisturiser, doing the same thing to the phone line insulation, and just causing it to slump on to the dust jacket.
Phone line insulation is not very robust from chemical solvents, but it does maintain flexibility over many years.
Personally, I’d be surprised if there was a chemical reaction between them, however, it’s pretty easy to test. Put them back in contact with each other (two ‘virgin’ parts). Maybe even use some tape to ensure a solid connection, then leave it in a safe place (say, in your garage or basement away from anything flammable) and see what happens after an hour, a day, a month? Personally, I’m guessing nothing. If phone cords and dust jackets have been around for long enough and are both commonly found in random boxes and junk drawers, you’d think it wouldn’t be totally unheard of. But, like I said, it’s a pretty simple experiment. Maybe we’ll all be surprised.
You said the box wasn’t exposed to heat, but are you sure? Was it in the sun? Was anything hot ever in there? Are there any batteries in there? Did it ever sit in a car for more than a few hours? If it was in a closet, was it up on shelf near a light bulb?
There could be so many possibilities and while I’ve never heard of a phone jack melting…melting because it came into contact with some acetate, wouldn’t be the first thing that would spring to mind.
The box has been a ‘stuff’ box for many years. In the previous 18 months it sat in a cupboard (nowhere near a light or heat source), and now it is in my office which is dark on the brightest days (faces west with wide verandah outside).
Whatever caused the problem has happened in recent weeks because I would have noticed the issue before: I have cause to rummage through the box every week or so for ‘that elusive thing I’m looking for’ and nothing has been apparent before today.
Some plastics can auto-catalyse and de-polymerise. PVC can, but it seems it mostly takes place at elevated temperatures, and may need the presence of HCl to initiate it. It isn’t impossible that there has been a reaction between the two plastics which has initiated an autocatalytic reaction.
The presence of plasticisers in both the cord and the film may be the culprit, or at least part of the story, as well. It is odd how sometimes very old cords can become slightly sticky, and I suspect this is related to what you have seen.
I’d like to see pix of the alleged “melting”. Soft plastics can flow slowly & adhere over time. Which vaguely resembles melting but is also obviously different.
This stuff being in the OP’s junk box also increases the odds the stuck parts were underneath something heavier which pressed the parts together for months or years on end.
Bottom line: IMO there was almost certainly nothing involving high temperatures going on.
PVC items with plasticizers to make them more bendable can soften other PVC (or unrelated plastics?) to the point that they become the consistency of Jell-O even in climate controlled conditions. A lot of wiring is coated in PVC because it’s thermally stable, but there’s so many different formulations out there for different uses that it could definitely be a case of cross-contamination by the plasticizer. I think some other non-PVC plastics might have this effect too, like Silicones and TPR and such, especially if they’re blended.
yep. the plasticizers can easily attack and soften other plastics. when I had a truck with vinyl seats, leaving CD cases on the seat for any length of time would “craze” the surface of the case. Also, older plastic model kits with vinyl tires could leave “impressions” on plastic parts left in contact with the tires.
It’s quite common for plastics, especially cheaper ones, to become goopy, sticky, brittle or just disintegrate over long periods of time. It can be from UV light, unstable formulations, contact with antagonistic materials etc. Burning isn’t necessary
Anecdote - My kids had one of these big ‘gliders’ made of a foam plastic. A part broke off and when we tried to use super glue to reattach it we found the super glue did an amazing job of melting the foam plastic. The ‘amazing’ part was the plastic condensed so much it looked like it was actually disappearing.
