It seems that improving the annealing process of printed parts from current 3D printers could, at best, reach the maximum crystallization of pure stereoregular

It seems that improving the annealing process of printed parts from current 3D printers could, at best, reach the maximum crystallization of pure stereoregular PLA polymers. Due to the two enantiomers of lactic acid, there are four different PLA polymers with different stereochemical structures: PLLA, PDLA, racemic PLA (PDLLA), and meso-PLA. It is only the the PLLA and PDLA stereoregular polymers that show crystalline characteristics. However, research indicates that mixing the PLLA and PDLA polymers allows the formation of a stereocomplex that has a much greater degree of crystallization. Note that this is a physical mixture of the two stereoregular polymers rather than a polymerization of the two lactic acid enantiomers, so the PLLA/PDLA stereocomplex (greater crystallization than either of the PLLA or PDLA polymers) is very different than the PDLLA polymer (which is amorphous, meaning non-crystalline). Perhaps what we need is a 3D printer that uses one PLLA filament and one PDLA filament. The two filaments would be melted and combined in the nozzle of the printer. As the mixture of the two polymers annealled, allowing the stereocomplex structure to form, the resulting material might have mechanical properties that are superior to either of the parent filaments.