Claims
- 1. A process for converting a non-homogeneous equilibrium block or graft copolymer into a homogeneous non-equilibrium polymer, comprising rapidly expanding a heated single-phase solution of said polymer in a supercritical fluid solvent across a small diameter nozzle, whereby said supercritical fluid solution is removed and the solid polymer is precipitated at a temperature which is no more than 30.degree. C. above the glass transition temperature of the polymer, and whereby, the non-equilibrium homogeneous morphology of the polymer is maintained.
- 2. A process according to claim 1 wherein the solubility of the polymer in the supercritical fluid solvent is at least about 0.0001% by weight.
- 3. A process according to claim 1 wherein the concentration of the polymers in the supercritical fluid is below the critical micelle concentration.
- 4. A process according to claim 1 wherein the supercritical fluid solvent is a member selected from the group consisting of chlorodifluoromethane, liquified CO.sub.2, N.sub.2 O, and C.sub.2 -C.sub.4 alkanes.
- 5. A process according to claim 1 wherein the polymer comprises:
- (a) a block or graff copolymer comprising two polymer units selected from the group consisting of polyolefins; the polystyrenes; the polyamides; silicone polymers; esters; polyacrylates; polycyanoacrylates; polymethacrylates; polycyanomethacrylates; polycarbonates; poly(dienes); poly(oxides); vinyl polymers; polyurethanes; polysulfones; cellulosic polymers; polyaminoacids; polyimides; and mixtures thereof.
- 6. A process according to claim 1 which is carried out at a pressure from about 2000 psi to about 10,000 psi and at a temperature from about 30.degree. C. t about 150.degree. C.
- 7. A process according to claim 1 wherein the polymer comprises polystyrene/poly(methyl methacrylate) block copolymer and the supercritical fluid solvent is chlorodifluoromethane.
- 8. A process according to claim 1 wherein the polymer is polystyrene/poly( 1,2-butadiene) block copolymer.
- 9. A solid, nonequilibrium homogeneous polymer prepared according to claim 1.
- 10. The process of claim 2, wherein the solubility of the polymer in the supercritical fluid solvent is from about 0.001% to about 5%.
Parent Case Info
This is a continuation of application Ser. No. 08/155,041, filed on Nov. 19, 1993, now U.S. Pat. No. 5,412,027, which was a Wrapper Continuation of application Ser. No. 07/675,764, filed on Mar. 27, 1991, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5412027 |
Shine et al. |
May 1995 |
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Continuations (2)
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Number |
Date |
Country |
Parent |
155041 |
Nov 1993 |
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Parent |
675764 |
Mar 1991 |
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