I’ve heard of plastics that are supposed to degrade. But I hadn’t expected to witness it myself.
I keep plastic carrier bags for re-use. They live in the cupboard under the sink, along with other re-usable containers and a few cleaning materials. I re-use the carrier bags when I go to the local shops, or take my old bottles and cans for recycling.
So today I was looking for old bags ready for their last use (‘cos they were going to get too dirty to re-use afterwards), and looked at the back of the cupboard. And there amidst the bags was a pile of flakes, from an old co-op carrier bag that had disintegrated. Nearby was a second bag that was just beginning to disintegrate.
Not sure how that happens. There was no sign of biological degrading (rotting/mould). The cupboard is dark, and wouldn’t get sunlight even when open. It doesn’t even get wet in there. The only thing that might be expected to provoke degradation is short bursts of moderate heat due to the pipes bringing water to the sink above.
These co-op bags are pretty good when new: more robust than those from some other suppliers. In future I’ll have to select them over others for early reuse, while they’re still intact.