METHOD OF IMPROVING ADHESION OF CARBON FIBERS WITH A POLYMERIC MATRIX

• US 20160311986A1
• Filed: 05/18/2016
• Published: 10/27/2016
• Est. Priority Date: 02/28/2012
• Status: Active Grant

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: Vautard, Frederic, Ozcan, Soydan, Paulauskas, Felix Leonard
• Granted Patent: US 10,457,785 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C08J 2333/04 esters
• CPC Class Codes: C08J 2363/00 Characterised by the use of epoxy resins; Derivatives of epoxy resins
• CPC Class Codes: C08J 2463/00 Characterised by the use of epoxy resins; Derivatives of epoxy resins
• CPC Class Codes: C08J 5/06 using pretreated fibrous materials
• CPC Class Codes: C08L 63/10 Epoxy resins modified by unsaturated compounds
• CPC Class Codes: Y10T 428/249948 Fiber is precoated
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]

Abstract

A functionalized carbon fiber having covalently bound on its surface a partially cured epoxy or amine-containing sizing agent, wherein at least a portion of epoxide or amine groups in the sizing agent are available as uncrosslinked epoxide or amine groups, which corresponds to a curing degree of epoxide or amine groups of no more than about 0.6. Composites comprised of these functionalized carbon fibers embedded in a polymeric matrix are also described. Methods for producing the functionalized carbon fibers and composites thereof are also described.

Claims

1-41. -41. (canceled)

42. A method of making a solid composite containing carbon fibers embedded in a polymeric matrix, the method comprising admixing carbon fibers with a polymer precursor resin, and curing the polymer precursor resin to form a cured polymeric matrix that contains said carbon fibers embedded therein, wherein said carbon fibers have covalently bonded on their surfaces a partially cured sizing agent comprised of an epoxy resin, wherein at least a portion of epoxide groups in the sizing agent are available as uncrosslinked epoxide groups, which corresponds to a curing degree of epoxide groups of no more than about 0.6.

43. The method of claim 42, wherein an amount of curing agent is selected that provides a curing degree of surface epoxide groups of no more than about 0.5.

44. The method of claim 42, wherein an amount of curing agent is selected that provides a curing degree of surface epoxide groups of no more than about 0.4.

45. The method of claim 42, wherein said polymeric matrix is a thermoset.

46. The method of claim 45, wherein said thermoset is derived from vinyl-addition polymerization of an unsaturated resin containing carbon-carbon double bonds.

47. The method of claim 46, wherein said unsaturated resin is a vinyl ester resin.

48. The method of claim 46, wherein said unsaturated resin is an unsaturated polyester resin.

49. The method of claim 42, wherein said polymeric matrix is derived from an acrylate or methacrylate resin.

50. The method of claim 42, wherein said polymeric matrix is a thermoplastic.

51. The method of claim 46, wherein said unsaturated resin is in admixture with at least one unsaturated reactive diluent that is cured with the unsaturated resin.

52. The method of claim 51, wherein said unsaturated reactive diluent is comprised of one or more compounds selected from the group consisting of styrene, divinyl benzenes, methacrylates, acrylates, and vinyl esters.

53. The method of claim 46, wherein said unsaturated resin is admixed with an unsaturated polymerizable monomer that includes a group reactive with epoxide in order for said carbon fibers to become covalently bonded with said unsaturated resin on curing the unsaturated resin.

54. The method of claim 53, wherein said group reactive with epoxide is a primary, secondary, or tertiary amine.

55. The method of claim 42, wherein the sizing agent includes reactive groups that react with and form covalent bonds with the carbon-carbon double bonds of the unsaturated resin.

56-85. -85. (canceled)

86. A method of making a solid composite containing carbon fibers embedded in a polymeric matrix, the method comprising admixing carbon fibers with a polymer precursor resin, and curing the polymer precursor resin to form a cured polymeric matrix that contains said carbon fibers embedded therein, wherein said carbon fibers have covalently bonded on their surfaces a partially cured amine-containing sizing agent, wherein at least a portion of amine groups in the sizing agent are available as uncrosslinked amine groups, which corresponds to a curing degree of amine groups of no more than about 0.6.

87. The method of claim 86, wherein an amount of curing agent is selected that provides a curing degree of surface amine groups of no more than about 0.5.

88. The method of claim 86, wherein an amount of curing agent is selected that provides a curing degree of surface amine groups of no more than about 0.4.

89. The method of claim 86, wherein said polymeric matrix is a thermoset.

90. The method of claim 86, wherein said thermoset is an acrylate resin, a vinyl sulfone resin, a vinyl ester resin, or a polyester resin that covalently bonds with amine groups of the sizing agent.

91. The method of claim 90, wherein said resin is an acrylate, a vinyl sulfone, a vinyl ester, a polyester, or an unsaturated resin containing an acrylate or a vinyl ester monomer in admixture with at least one unsaturated reactive diluent.

92. The method of claim 91, wherein said unsaturated reactive diluent is selected from the group consisting of styrene, divinyl benzenes, methacrylates, and vinyl esters.

93. The method of claim 86, wherein said polymeric matrix is a thermoplastic derived from a monomer containing a functionality that covalently bonds with the uncrosslinked amine groups of the sizing agent.

94. The method of claim 93, wherein said functionality is selected from an ester, a carboxylic acid, a urethane, an aldehyde, and a ketone.

95. The method of claim 93, wherein said thermoplastic is selected from polyether ether ketone (PEEK), polycarbonates, polymethacrylic acids, polyesters, polylactic acids, polyglycolic acids, polymethacrylates, polymethylacryaltes, Nylon 6, Nylon 6,6, polysulfones, polyvinylalcohols, polyimides, and thermoplastic polyurethanes.