Hi all,

I just finished writing a comprehensive article on "brittle plastic disease" for MacDat's knowledge base. Notably, it includes electron microscope photography of a brittle part which shows exactly what's happening at a microscopic level.

A big thanks goes out to polymatt for letting me use the photos, and for Blaise at Cubic Labs for helping him analyze the plastics. You should definitely watch his video here:

Here's a link to the article: https://www.macdat.net/repair/kb/brittle_plastic_disease.html

Let me know if there's anything you think I should add/change.

Like the simplistic webpage.

I would change the white arrows used to point towards areas being zoomed to a different color, like red or green.

Oh, those weren't my photos. They're screen grabs from polymatt's video, so they were already like that. I would have probably made them red if I was marking them myself.

>> 3lectr1c said:

Hi all, I just finished writing a comprehensive article on "brittle plastic disease" for MacDat's knowledge base. Notably, it includes electron microscope photography of a brittle part which shows exactly what's happening at a microscopic level. A big thanks goes out to polymatt for letting me use the photos, and for Blaise at Cubic Labs for helping him analyze the plastics. You should definitely watch his video here: Here's a link to the article: https://www.macdat.net/repair/kb/brittle_plastic_disease.html Let me know if there's anything you think I should add/change. Click to expand...

Thanks so much for sharing.

I watched the video and the summary of the brittleness explanation was that the use of a brominated flame retardant combined with off-gassing caused micro-fissures which led to the case falling apart.

Honestly, I wish we had no flame retardants at all for the sake of not having to de-yellow so much, but this insight into brittleness adds yet another important reason.

Not to mention the fact that it's not so great for the environment....

I wonder how modern plastics will fare 25-30 years from now?

Something I find interesting is that plastics from 50-80 years ago (vinyl records, for example), are about as flexible and solid as the day they were pressed, provided they're stored and cared for properly (even those that are severely abused actually hold up pretty well too, in the sense that they don't get brittle). I suspect that one of the reasons for it is a lack of bromine, and also I suppose vinyl is a more stable material than ABS for reasons I can't begin to know.

That said, if a record were to exhibit micro fissures and craters from off gassing constituent chemicals similarly to ABS, it seems to me that the vast majority of them would have been rendered unplayable by now regardless of how well cared for, as that kind of deterioration would almost certainly cause severely damage or destruction of the fine grooves, if the records didn't crumble into pieces from basic handling first.

c

I don't know how widespread BFRs were in plastics - not all plastics with them are marked ABS-FR or something of that nature. You'd need to do chemical analysis of a wide sample range of different brittle and non-brittle plastics to find anything conclusive on what different factors are most important in causing plastic to deteriorate in this way. All we can really say, as useful as the analysis on the Halikan's plastics is, is that in this case, BFRs are likely the main factor behind its deterioration.

I don't think it's unreasonable to say that the same is likely true of the Mac plastics stamped as ABS-FR, but I don't think we can say anything conclusive about all the many different plastics found on, say, vintage laptops which in my experience are usually marked ABS-PC.

Also worth noting that this doesn't confirm that BFRs are the cause behind plastics yellowing. The Halikan's plastics looked more or less the correct color, based on original marketing photos I have. I'm not saying this isn't true, just that this particular testing doesn't prove/disprove that.


The Halikan's original broken plastics


Original marketing photo from Chaplet Systems