Machine Direction–Oriented Film Technology

Shear Piezoelectricity of Poly(l-lactide) Films Manufactured by Extrusion–Orientation: An Insight on Process–Structure–Property Relationships

“…This configuration ensures flexibility, conveniency, and good film quality at our laboratory scale. However, a continuous process could be easily envisioned at the industrial scale using dedicated calendaring–MDO units with a direct coupling. , …”

“…Actually, the processing of PLA into US-PLA could be easily handled at the industrial scale by standard processing technologies of the plastic/textile industry. Incorporation of additives into PLA could be done by twin-screw extrusion, and its subsequent transformation into US-PLA films only requires single-screw extruders with machine-direction orientation stations (MDO). , Intense uniaxial elongational flows are applied by MDO, and this process continuously manufactures highly oriented films with good control over orientation conditions (draw ratio, strain rate, stretching temperature, annealing temperature in stretched state, etc.). MDO consequently seems to be an ideal processing technique for large-scale production of US-PLA films with enhanced shear piezoelectric properties, but to the best of our knowledge, extrusion processing coupled to MDO has never been investigated for this purpose.…”

Effect of Temperature on Flow-Induced Crystallization of Isotactic Polypropylene: A Molecular-Dynamics Study

“…Commercially, flow is applied to cast or blown films using a carefully designed apparatus made by rolls, known as machine direction orientation (MDO) . During the MDO process, the semicrystalline film is heated to a temperature close to the melting temperature of the polymer, and then it is uniaxially stretched at a draw ratio close to 10, or even more in some cases . Finally, the film is thermally treated in order to lock the new properties obtained from the stretching.…”

“…Finally, the film is thermally treated in order to lock the new properties obtained from the stretching. This process has been proven to have a strong effect on the microstructure transformation from spherulitic to fibrillar and enhances barrier properties and tensile strength at break . In the laboratory scale, it has been shown that by applying elongational flow with high strain rate to a supercooled melt at a temperature close to the melting point, not only morphology is affected, but kinetics as well, resulting in an increase of up to 6 orders of magnitude of the crystallization rate and in an ultrahigh performance …”