Selective, controlled manipulation of polymers
AssigneeMassachusetts General Hospital
InventorOrhun MURATOGLU
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Abstract
The present invention provides partial and complete shielding approaches to alter the cross-linking characteristics of irradiated polymers, such as polyethylene. Irradiated polymers and fabricated articles, such as medical prosteses, comprising irradiated polymers also are provided.
Claims18
A cross-linked polymeric composition comprising polymers, wherein the polymeric composition has a gradient of cross-link density in a direction perpendicular to the direction of irradiation, wherein a part of the polymeric composition was preferentially shielded with a shield of varying shape, cross-section or thickness in order to provide the gradient of crosslink density to the part shielded with the shield of the varying shape, cross-section or thickness, wherein the shape of the shield or cross section is rectangular, circular, triangular, square, shape of an interior or exterior part of a medical implant, ring-shaped, disc-shaped, or a combination of shapes, and wherein the gradient of crosslink density is in a direction perpendicular to the direction of irradiation on the preferentially shielded polymeric composition.
A method of making a cross-linked polymeric composition comprising polymers, wherein the cross-linked polymeric composition has a gradient of crosslink density in a direction perpendicular to the direction of irradiation, wherein the method comprising:
- a) shielding a part of the polymeric composition preferentially with a shield of varying shape, cross-section or thickness, wherein the shape of the shield or cross section is rectangular, circular, triangular, square, shape of an interior or exterior part of a medical implant, ring-shaped, disc-shaped, or a combination of shapes;
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- b) irradiating the preferentially shielded polymeric composition of a) in order to provide the gradient of crosslink density to the part shielded with the shield of the varying shape, cross-section or thickness, and wherein the gradient of crosslink density is in a direction perpendicular to the direction of irradiation on the preferentially shielded polymeric composition.
A medical prosthesis comprising an irradiated polymeric composition comprising polymers, wherein the prosthesis has a gradient of crosslink density in a direction perpendicular to the direction of irradiation, wherein a part of the polymeric composition was preferentially shielded with a shield of varying shape, cross-section or thickness in order to provide the gradient of crosslink density to the part shielded with the shield of the varying shape, cross-section or thickness, wherein the shape of the shield or cross section is rectangular, circular, triangular, square, shape of an interior or exterior part of a medical implant, ring-shaped, disc-shaped, or a combination of shapes, and wherein the gradient of crosslink density is in a direction perpendicular to the direction of irradiation on the preferentially shielded polymeric composition.
A method of making a medical prosthesis comprising an irradiated polymeric composition, wherein the medical prosthesis has a gradient of crosslink density in a direction perpendicular to the direction of irradiation, the method comprising:
- a) preferentially shielding a part of the polymeric composition with a shield of varying shape, cross-section or thickness, wherein the shape of the shield or cross section is rectangular, circular, triangular, square, shape of an interior or exterior part of a medical implant, ring-shaped, disc-shaped, or a combination of shapes;
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- b) irradiating the preferentially shielded polymeric composition of a) in order to provide the gradient of crosslink density to the part shielded with the shield of the varying shape, cross-section or thickness, and wherein the gradient of crosslink density is in a direction perpendicular to the direction of irradiation on the preferentially shielded polymeric composition.
Dependencies are inferred from the claim text.