Aida said the new material is as strong as petroleum-based plastics but breaks down into its original components when exposed to salt.
If this means that it does not break down when exposed to just water, that’s a pretty big deal. Water solubility has been the major issue making biodegradable plastics useless for food packaging (typically you want to either keep the food wet and water in, or dry and water out - either way water permeability is a problem).
Of course most foods also contain salt, so… I guess that’s why the article talks about coatings. If the material has to be coated to keep it from breaking down too fast, what is the point? either the coating will prevent it from breaking down, or it just moves the problem to the coating not breaking down.
Food is a reasonable target for biodegradable packaging because you don’t really expect the food to sit around for more than a year (for long-term food packaging you just wouldn’t use a biodegradable material).
Packaging products that might have a long shelf life is more problematic. If the material breaks down in saltwater then it will start breaking down if someone picks it up with sweaty or recently washed hands.
If the material has to be coated to keep it from breaking down too fast, what is the point?
Presumably you could only coat certain faces of the material (like ones touching food). Or maybe the coating could degrade in another more time-known fashion. So if the coating would be expected to last no more then 3 years then after the plastic could start to degrade.
If this means that it does not break down when exposed to just water, that’s a pretty big deal. Water solubility has been the major issue making biodegradable plastics useless for food packaging (typically you want to either keep the food wet and water in, or dry and water out - either way water permeability is a problem).
Of course most foods also contain salt, so… I guess that’s why the article talks about coatings. If the material has to be coated to keep it from breaking down too fast, what is the point? either the coating will prevent it from breaking down, or it just moves the problem to the coating not breaking down.
Food is not the only thing that gets packaged. The worst example that comes to my mind is the way they package microSD cards.
Food is a reasonable target for biodegradable packaging because you don’t really expect the food to sit around for more than a year (for long-term food packaging you just wouldn’t use a biodegradable material).
Packaging products that might have a long shelf life is more problematic. If the material breaks down in saltwater then it will start breaking down if someone picks it up with sweaty or recently washed hands.
Presumably you could only coat certain faces of the material (like ones touching food). Or maybe the coating could degrade in another more time-known fashion. So if the coating would be expected to last no more then 3 years then after the plastic could start to degrade.