Method for making a porous polymeric material
First Claim
1. A process for making a porous polymeric material, comprising the steps of:
- a. selecting a polymer;
b. identifying a first solvent that is capable of substantially dissolving a solid form of the polymer;
c. identifying a second solvent that does not substantially dissolve the polymer in solid form, but instead merely swells the solid polymer;
d. providing at least sufficient first solvent to said polymer as to substantially dissolve the polymer in the first solvent to form a solution;
e. adding a quantity of the second solvent to the solution, whereupon an entire volume of solution begins to gel without forming a precipitate;
f. continuing the adding of the second solvent until a viscosity of the gel increases to a point where the gel is suitable for shape-forming;
g. shape-forming the gel; and
h. removing the first and second solvents from the gel.
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Accused Products
Abstract
Porous polymers having a plurality of openings or chambers that are highly convoluted, with each chamber being defined by multiple, thin, flat partitions are produced by a new gel enhanced phase separation technique. In a preferred embodiment, a second liquid is added to a polymer solution, the second liquid causing the solution to increase in viscosity. With sufficient polymer and second liquid present, the increase in viscosity can be up to that of a gel. The gel can then be shaped as needed. Subsequent solvent extraction leaves the porous polymeric body of defined shape. The porous polymers have utility as medical prostheses, the porosity permitting ingrowth of neighboring tissue. A second material may be incorporated into the chambers, thereby creating a microstructure filling the voids of the macrostructure. A porous polymeric body manufactured by this process may incorporate biologically active agents, and which agents may be delivered in a time-staged delivery manner, where differing drugs may be delivered over differing periods.
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Citations
36 Claims
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1. A process for making a porous polymeric material, comprising the steps of:
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a. selecting a polymer;
b. identifying a first solvent that is capable of substantially dissolving a solid form of the polymer;
c. identifying a second solvent that does not substantially dissolve the polymer in solid form, but instead merely swells the solid polymer;
d. providing at least sufficient first solvent to said polymer as to substantially dissolve the polymer in the first solvent to form a solution;
e. adding a quantity of the second solvent to the solution, whereupon an entire volume of solution begins to gel without forming a precipitate;
f. continuing the adding of the second solvent until a viscosity of the gel increases to a point where the gel is suitable for shape-forming;
g. shape-forming the gel; and
h. removing the first and second solvents from the gel. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 29, 30, 31, 33, 34, 35, 36)
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2. A process for making a porous polymeric material, comprising the steps of:
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a. selecting a polymer;
b. identifying a first liquid that is capable of substantially completely dissolving a solid form of the polymer;
c. identifying a second liquid that does not substantially dissolve the polymer in solid form, but instead merely swells the solid polymer by being absorbed into its molecular structure, thereby increasing the mass of the polymer by at least about 35 percent by weight;
d. dissolving the polymer in the first liquid to form a solution;
e. adding a quantity of the second liquid to the solution, whereupon the entire volume of solution begins to gel without forming a precipitate;
f. continuing the adding of the second liquid until a viscosity of the gel increases to a point where the gel is suitable for shape-forming;
g. shape-forming the gel; and
h. removing the first and second liquids from the gel.
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3. A process for making a porous polymeric material, comprising the steps of:
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a. selecting a polymer;
b. identifying a first liquid that is capable of substantially completely dissolving a solid form of the polymer;
c. identifying a second liquid that does not substantially dissolve the polymer in solid form, but instead merely swells the solid polymer by being absorbed into its molecular structure, thereby increasing the mass of the polymer by at least about 35 percent by weight;
d. dissolving the polymer in the first liquid to form a solution;
e. adding a quantity of the second liquid to the solution, whereupon the entire volume of solution begins to increase in viscosity without visibly separating into multiple phases;
f. continuing the adding of the second liquid until the viscosity increases to a point where solution is suitable for shape-forming;
g. shape-forming the solution; and
h. removing at least the first liquid from the solution.
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15. A process for creating a composite body comprising a porous polymeric body using a gel enhanced phase separation technique, the process comprising:
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a. selecting a polymer for gelation;
b. identifying suitable first and second solvents for said polymer;
c. dissolving said polymer into said first solvent to form a solution having a quantity of polymer that will be appropriate for subsequent gelation;
d. adding a suitable second solvent to the solution that causes the solvent/polymer solution to thicken into a gel;
e. placing the gel in contact with at least one other material; and
f. removing the first and second solvent, thereby leaving a porous polymer and the at least one other material, wherein said porous polymer and said at least one other material are mechanically bound to each other. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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32. A process for making a porous polymeric body, substantially as herein described in the specification and as shown in the drawings.
Specification