Axially oriented confined crystallization multilayer films
A method of forming a confined crystallization multilayer film includes coextruding a plurality of first polymer layers and a plurality of second polymer layer to form a multilayer film wherein each first polymer layer is sandwiched between second polymer layers and axially orienting the multilayer film at a temperature below the melting temperature (T m ) of the second polymer layer and to a thickness such that each first polymer layer forms a high aspect ratio substantially crystalline lamellae.
1. A method of forming a confined crystallization multilayer film, the method comprising:
providing a multilayer film that includes a plurality of first polymer layers and a plurality of second polymer layers wherein each first polymer layer is sandwiched between second polymer layers, the first polymer layers having a melting temperature (T m ) below the melting temperature (T m ) of the second polymer layers; and
axially orienting the multilayer film at a temperature below the melting temperature (T m ) of the second polymer layers and to a thickness such that each first polymer layer forms a high aspect ratio substantially crystalline lamellae, the multilayer film being substantially impermeable to gas diffusion.
2. The method of claim 1 , wherein the first polymer layers and the second polymer layers are coextruded to form the multilayer film.
3. The method of claim 1 , the multilayer film being biaxially oriented after coextrusion.
4. The method of claim 1 , the first polymer layers comprising a first polymer selected from the group consisting of high-density polyethylene, polyethylene oxide, polyamide, polyester, polycaprolactone, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene, copolymers thereof, and combinations thereof.
5. The method of claim 1 , the second polymer layers comprising a second polymer selected from the group consisting of polypropylene, polystyrene, maleic anhydride-modified polypropylene (PPgMA), PET, polycarbonate, acrylics/methacrylics, polyesters, polyurethanes, polyamides, polyimides, polyphosphazenes, epoxy resins, hybrid polyester polymers, nylon, low-density polyethylene, polyoxymethylene, copolymers thereof, and combinations thereof.
6. The method of claim 1 , the first polymer layers after axial orientation having an average thickness of about 10 nm to about 500 nm.
7. The method of claim 1 , the aspect ratio of the substantially crystalline lamellae being at least about 5.
8. The method of claim 1 , the second polymer layers being immiscible or partially miscible with the first polymer layers.
9. The method of claim 1 , wherein the multilayer film is drawn at a draw ratio of about 3:3 to about 5:5.
10. The method of claim 1 , wherein the multilayer film is axially oriented at a temperature above the melting temperature (T m ) of the first polymer layers and below the melting temperature (T m ) of the second polymer layers and to a thickness such that each first polymer layer forms a high aspect ratio substantially crystalline lamellae.
11. The method of claim 1 , wherein the multilayer film is axially oriented at a temperature at or below the melting temperature (T m ) of first polymer layers and between the glass transition temperature (T g ) and the cold crystallization temperature (T cc ) of the second polymer layers.
12. The method of claim 11 , wherein the first polymer layers are melt recrystallized after axial orientation to reduce gas permeability of the multilayer film.
13. A method of forming a confined crystallization multilayer film, the method comprising:
providing a multilayer film that includes a plurality of first polymer layers and a plurality of second polymer layers wherein each first polymer layer is sandwiched between second polymer layers, the first polymer layers having a melting temperature (T m ) below the melting temperature (T m ) of the second polymer layers; and
axially orienting the multilayer film at a temperature above the melting temperature (T m ) of the first polymer layers and below the melting temperature (T m ) of the second polymer layers and to a thickness such that each first polymer layer forms a high aspect ratio substantially crystalline lamellae, the multilayer film being substantially impermeable to gas diffusion.
14. The method of claim 13 , wherein the first polymer layers and the second polymer layers are coextruded to form the multilayer film.
15. The method of claim 13 , the multilayer film being biaxially oriented after coextrusion at a draw ratio of about 3:3 to about 5:5, the first polymer layers after biaxial orientation having an average thickness of about 10 nm to about 500 nm.
16. The method of claim 13 , the substantially crystalline lamellae extending in a plane substantially parallel to the multilayer film and the aspect ratio of the substantially crystalline lamellae being at least about 5.
17. The method of claim 13 , the second polymer layers being immiscible or partially miscible with the first polymer layers.
18. The method of claim 17 , the first polymer layers comprising a first polymer selected from the group consisting of high-density polyethylene, polyethylene oxide, polyamide, polyester, polycaprolactone, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene, copolymers thereof, and combinations thereof.
19. The method of claim 17 , the second polymer layers comprising a second polymer selected from the group consisting of polypropylene, polystyrene, maleic anhydride-modified polypropylene (PPgMA), PET, polycarbonate, acrylics/methacrylics, polyesters, polyurethanes, polyamides, polyimides, polyphosphazenes, epoxy resins, hybrid polyester polymers, nylon, low-density polyethylene, polyoxymethylene, copolymers thereof, and combinations thereof.
20. A method of forming a confined crystallization multilayer film, the method comprising:
providing a multilayer film that includes a plurality of first polymer layers and a plurality of second polymer layers wherein each first polymer layer is sandwiched between second polymer layers, the first polymer layers having a melting temperature (T m ) below the melting temperature (T m ) of the second polymer layers; and
axially orienting the multilayer film at a temperature at or below the melting temperature (T m ) of the first polymer layers and between the glass transition temperature (T g ) and the cold crystallization temperature (T cc ) of the second polymer layers to a thickness such that each first polymer layer forms a high aspect ratio substantially crystalline lamellae, the multilayer film being substantially impermeable to gas diffusion.
21. The method of claim 20 , wherein the first polymer layers are melt recrystallized after axial orientation to reduce gas permeability of the multilayer film.
22. The method of claim 21 , wherein the first polymer layers and the second polymer layers are coextruded to form the multilayer film.
23. The method of claim 21 , the multilayer film being biaxially oriented after coextrusion at a draw ratio of about 3:3 to about 5:5, the first polymer layers after biaxial orientation having an average thickness of about 10 nm to about 500 nm.
24. The method of claim 21 , the substantially crystalline lamellae extending in a plane substantially parallel to the multilayer film and the aspect ratio of the substantially crystalline lamellae being at least about 5.
25. The method of claim 21 , the second polymer layers being immiscible or partially miscible with the first polymer layers.
26. The method of claim 25 , the first polymer layers comprising a first polymer selected from the group consisting of high-density polyethylene, polyethylene oxide, polyamide, polyester, polycaprolactone, polyvinylidene fluoride, polytetrafluoroethylene, polyvinylidene, copolymers thereof, and combinations thereof.
27. The method of claim 25 , the second polymer layers comprising a second polymer selected from the group consisting of polypropylene, polystyrene, maleic anhydride-modified polypropylene (PPgMA), PET, polycarbonate, acrylics/methacrylics, polyesters, polyurethanes, polyamides, polyimides, polyphosphazenes, epoxy resins, hybrid polyester polymers, nylon, low-density polyethylene, polyoxymethylene, copolymers thereof, and combinations thereof.
28. The method of claim 1 , the first polymer layers comprising polyethylene oxide (PEO) and the second polymer layers comprising polypropylene.
29. The method of claim 1 , the first polymer layers comprising polyvinylidene fluoride-polytetrafluoroethylene (PVDF-TFE) and the second polymer layers comprising PET.
30. The method of claim 13 , the first polymer layers comprising polyethylene oxide (PEO) and the second polymer layers comprising polypropylene.
31. The method of claim 13 , the first polymer layers comprising PVDF-TFE and the second polymer layers comprising PET.
32. The method of claim 20 , the first polymer layers comprising PEO and the second polymer layers comprising polypropylene.
33. The method of claim 20 , the first polymer layers comprising PVDF-TFE and the second polymer layers comprising PET.