Self-reinforced ultra-high molecular weight polyethylene composites

• US 5,824,411 A
• Filed: 06/07/1995
• Issued: 10/20/1998
• Est. Priority Date: 08/20/1993
• Status: Expired due to Term

• Current Assignee: Poly-Med, Inc.
• Original Assignee: Poly-Med, Inc.
• Inventors: Deng, Meng, Shalaby, Shalaby W.
• Primary Examiner(s): WEISBERGER, RICHARD C
• Application Number:
  US08/480,848
• Time in Patent Office: 1,231 Days
• Field of Search: 428/364, 428/373, 428/902, 428/397, 428/500, 264/138, 264/163, 264/322, 264/323, 627/18, 627/23, 627/11
• US Class Current: 428/364
• CPC Class Codes: A61L 27/48 with macromolecular fillers
• CPC Class Codes: A61L 31/129 containing macromolecular fillers
• CPC Class Codes: B29C 67/24 characterised by the choice of material
• CPC Class Codes: B29C 70/04 comprising reinforcements only, e.g. self-reinforcing plastics
• CPC Class Codes: B29C 70/06 Fibrous reinforcements only
• CPC Class Codes: B29C 70/465 and impregnating by melting a solid material, e.g. sheets, powders of fibres
• CPC Class Codes: B29C 70/50 for producing articles of indefinite length, e.g. prepregs, sheet moulding compounds [SMC] or cross moulding compounds [XMC]
• CPC Class Codes: B29K 2023/0683 UHMWPE, i.e. ultra high molecular weight polyethylene
• CPC Class Codes: B29K 2105/101 Oriented
• CPC Class Codes: B29K 2105/24 crosslinked or vulcanised
• CPC Class Codes: B29L 2031/7532 Artificial members, protheses
• CPC Class Codes: C08L 2203/02 for biomedical use
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2205/16 Fibres; Fibrils
• CPC Class Codes: C08L 23/06 Polyethene
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: Y10S 428/902 High modulus filament or fiber
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/2973 Particular cross section
• CPC Class Codes: Y10T 428/31855 : Of addition polymer from unsaturated monomers

Abstract

The invention provides composites of ultra-high molecular weight polyethylene reinforced with ultra-high molecular weight polyethylene anisotropic reinforcement of high strength and modulus. The composites have superior mechanical properties relative to non-filled ultra-high molecular weight polyethylene, including higher strength, impact strength, increased creep resistance, and improved modulus. The composites may be sterilized for biomedical use, using gamma radiation and other techniques. Further, the composites are resistant to the effect of body fluids and have lower creep rates so that they will provide implant life. The composites may be cross-linked by exposure to an acetylene environment. Also, the composites find use in other high strength, high impact applications such as sports equipment.

Claims

1. A composite of high tensile and impact strength, elastic modulus, and creep resistance, the composite comprising:

an essentially non-oriented matrix of an ultra-high molecular weight polyethylene polymer; and

a reinforcement of ultra-high molecular weight polyethylene dispersed in and bonded to said matrix in sufficient amount to increase the tensile and impact strength, elastic modulus, and creep resistance of the composite above the tensile and impact strength, elastic modulus, and creep resistance of non-reinforced ultra-high molecular weight polyethylene matrix polymer, the reinforcement comprising up to about 12 percent by weight of the composite, the reinforcement selected from the group consisting of fibers, plies of fibers, and textile constructs;

wherein a unidirectionally reinforced segment of the composite exhibits a transverse strength equal to or greater than the strength of a non-reinforced ultra-high molecular weight polyethylene matrix polymer of substantially similar dimensions.

2. The composite of claim 1, wherein at least some of the matrix ultra-high molecular weight polymer is cross-linked.

3. The composites of claim 1, wherein the composite is sterilizable by a process comprising exposure to gamma irradiation.

4. The composite of claim 1, wherein the composite is sterilized and cross-linked, said sterilization and cross-linking produced by a process comprising exposing the composite to high energy radiation in the presence of an acetylene-containing environment.

5. The composite of claim 1, wherein impact strength of the composite after irradiation with a high energy beam of radiation is greater than impact strength of unreinforced ultra-high molecular weight polyethylene of the matrix polymer subjected to the same radiation.

6. A composite structure of self-reinforced ultra-high molecular weight polyethylene comprising:

an at least partially cross-linked, essentially non-oriented, matrix of an ultra-high molecular weight polyethylene polymer; and

a reinforcement of ultra-high molecular weight polyethylene polymer dispersed in and bonded to said matrix in sufficient amount to increase the tensile and impact strength, elastic modulus, and creep resistance of the composite above the tensile and impact strength, elastic modulus, and creep resistance of non-reinforced ultra-high molecular weight polyethylene matrix polymer, the reinforcement comprising up to about 12 percent by weight of the composite, the reinforcement selected from the group consisting of fibers, plies of fibers, and textile constructs;

wherein a unidirectionally reinforced segment of the composite exhibits a transverse strength equal to or greater than the strength of non-reinforced ultra-high molecular weight polyethylene matrix polymer of substantially similar dimensions.

7. The composite structure of claim 6, wherein the cross-linking is produced by a process comprising exposing the structure to high energy radiation in an acetylene-containing environment.