Methods and pressure vessels for solid-state microcellular processing of thermoplastic rolls or sheets
Disclosed herein are methods and pressure vessels for solid-state microcellular processing of thermoplastic rolls and sheets. In one embodiment, the present invention is directed to a method for making a gas impregnated interleaved roll, which method comprises: providing a pressure vessel having an internal pressure chamber and a rotatable shaft horizontally positioned within the pressure chamber; placing an interleaved roll about the rotatable shaft and within the pressure chamber, wherein the interleaved roll is made from a thermoplastic material sheet interleaved together with a gas-channeling material sheet; pressurizing the pressure chamber to a selected pressure; rotating the rotatable shaft having the interleaved roll thereabouts (thereby rotating the interleaved roll) while under pressure for a selected period of time; and depressurizing the internal chamber to yield the gas impregnated interleaved roll. In other embodiments, the invention is directed to multi-chambered pressure vessels for gas impregnation of thermoplastic rolls, sheets, and films.
1. A method for making a gas impregnated interleaved roll, comprising:
providing a pressure vessel having an internal pressure chamber and a rotatable shaft positioned within the pressure chamber;
placing an interleaved roll about the rotatable shaft and within the pressure chamber, wherein the interleaved roll is made from a thermoplastic material sheet interleaved together with a gas-channeling material sheet;
pressurizing the pressure chamber to a selected pressure; rotating the rotatable shaft having the interleaved roll thereabouts while under pressure for a selected period of time; and
depressurizing the internal chamber to yield the gas impregnated interleaved roll.
2. The method of claim 1 wherein the thermoplastic material sheet is made of polyetherimide (PEI) or polyetherketoneketone (PEKK).
3. The method of claim 2 wherein the selected pressure ranges from about 3.5 MPa to about 7.1 MPa.
4. The method of claim 3 wherein the selected period of time is greater than about 10 hours.
5. A method for making a gas impregnated interleaved roll, comprising:
providing a pressure vessel having an internal pass-through multi-chambered cavity, wherein the multi-chambered cavity includes at least two outer pressure chambers sandwiching a central pressure chamber, and wherein a rotatable shaft is longitudinally positioned within each of the two outer and central pressure chambers of the multi-chambered cavity;
placing an interleaved roll about the rotatable shaft and within one of the two outer pressure chambers, wherein the interleaved roll is made from a thermoplastic material sheet interleaved together with a gas-channeling material sheet;
pressurizing the one of the two outer pressure chamber to a first selected pressure;
rotating the rotatable shaft having the interleaved roll thereabouts while under the first selected pressure for a first selected period of time;
conveying the interleaved roll to the central pressure chamber while under pressure;
rotating the rotatable shaft having the interleaved roll thereabouts while under a second selected pressure for a second selected period of time;
conveying the interleaved roll to the other one of the two outer pressure chambers while under pressure;
rotating the rotatable shaft having the interleaved roll thereabouts while under a third pressure for a third selected period of time; and
depressurizing the other one of the two outer pressure chambers to yield the gas impregnated interleaved roll.
6. The method of claim 5 wherein the thermoplastic material sheet is made of polyethylene terephthalate (PET), polystyrene (PS), polycarbonate (PC), or acrylonitrile butadiene styrene (ABS).
7. The method of claim 6 wherein the selected first, second, and third pressures each range from about 3.5 MPa to about 7.1 MPa.
8. The method of claim 7 wherein the sum of the selected first, second, and third period of times is greater than about 1 hour.
9. The method of claim 8 wherein the selected first, second, and third pressures are each about the same.