5. Conclusion

The multi-nanolayer coextrusion process enables several polymers to be combined in a very high number of alternating layers (up to several thousand). This increase in the number of layers is accompanied by a reduction in the individual thickness of each layer, which can reach the nanometric scale if process flows are well controlled. Numerous studies have shown that nanostratification can, in some cases, lead to substantial improvements in properties, well beyond the predictions of mixing laws, linked to complex interfacial and/or confinement phenomena, and thus to changes in polymer behavior.

Thanks to these improved properties, the process has met with a favorable response from the industrial world right from the start, resulting in a constant need to develop tools for reducing layer thickness. Although a few tools are now on the market, the number of applications...