Unfortunately the recyclability and the lack of toxicity are contradictory, they cannot be satisfied simultaneously for this kind of materials.
As long as the 2-dimensional polymeric sheets do not decompose, they will not be toxic, as they cannot enter a living cell (in the form of fine dust they could cause the same problems as any mineral dust, e.g. respiratory damage through purely mechanical action).
However if they do not decompose, they can be recycled only by burning.
If they can be decomposed into monomers by heat, light or chemicals, then the monomer can be recycled. However in that case some spontaneous decomposition will also occur in old objects made of the 2-dimensional polymer and the released monomer molecules would cause toxicity problems.
So only one of these 2 features must be chosen and optimized.
Plastics can be toxic by leaching additives without the polymer itself breaking down. Moreover, much of the damage caused by microplastics (i.e. only mechanically broken down) is poorly understood. At the very least, they seem to harbour novel collections of microbes that aren't necessarily benign.
Poly(lactic acid) can be decomposed into lactate monomers by water, and the released lactate monomer can be oxidized to pyruvate and used as food by the Krebs cycle, or converted to glucose via gluconeogenesis. The lethal dose is in the grams per kilogram, so it won't cause toxicity problems.
As long as the 2-dimensional polymeric sheets do not decompose, they will not be toxic, as they cannot enter a living cell (in the form of fine dust they could cause the same problems as any mineral dust, e.g. respiratory damage through purely mechanical action).
However if they do not decompose, they can be recycled only by burning.
If they can be decomposed into monomers by heat, light or chemicals, then the monomer can be recycled. However in that case some spontaneous decomposition will also occur in old objects made of the 2-dimensional polymer and the released monomer molecules would cause toxicity problems.
So only one of these 2 features must be chosen and optimized.