CONTINUOUS BORON NITRIDE NANOTUBE YARNS AND METHODS OF PRODUCTION

• US 20150033937A1
• Filed: 07/30/2014
• Published: 02/05/2015
• Est. Priority Date: 07/30/2013
• Status: Active Grant

• Current Assignee: University of New Hampshire
• Original Assignee: University of New Hampshire
• Inventors: Lashmore, David S., Bennett, Tyler
• Granted Patent: US 10,458,049 B2
• Time in Patent Office: Days
• US Class Current: 89/36.02
• CPC Class Codes: C01B 21/0641 Preparation by direct nitridation of elemental boron
• CPC Class Codes: C01B 21/0646 Preparation by pyrolysis of boron and nitrogen containing compounds
• CPC Class Codes: C01B 21/0648 After-treatment, e.g. grinding, purification transformation of hexagonal into cubic or wurtzitic boron nitride C04B35/5831
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/13 Nanotubes
• CPC Class Codes: C01P 2004/136 Nanoscrolls, i.e. tubes having a spiral section
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C04B 2235/524 Non-oxidic, e.g. borides, carbides, silicides or nitrides
• CPC Class Codes: C04B 2235/526 characterised by the length of the fibers
• CPC Class Codes: C04B 2235/5264 characterised by the diameter of the fibers
• CPC Class Codes: C04B 2235/5284 Hollow fibers, e.g. nanotubes
• CPC Class Codes: C04B 35/5831 based on cubic boron nitrides or Wurtzitic boron nitrides, including crystal structure transformation of powder
• CPC Class Codes: C04B 35/6229 based on boron nitride
• CPC Class Codes: C04B 35/80 Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: D02G 3/02 Yarns or threads characterised by the material or by the materials from which they are made
• CPC Class Codes: D02G 3/16 Yarns or threads made from mineral substances
• CPC Class Codes: D02G 3/442 Cut or abrasion resistant yarns or threads
• CPC Class Codes: D10B 2101/14 Carbides; Nitrides; Silicides; Borides
• CPC Class Codes: D10B 2507/00 Sport; Military
• CPC Class Codes: F41H 1/02 Armoured or projectile- or missile-resistant garments; Composite protection fabrics F41H5/04 takes precedence
• CPC Class Codes: F41H 5/02 : Plate construction

Abstract

A method and apparatus for producing boron nitride nanotubes and continuous boron nitride nanotube yarn or tapes is provided. The apparatus includes rotating reaction tubes that allow for continuous chemical vapor deposition of boron nitride nanotubes. The rotation of the reaction tubes allows the boron nitride nanotubes to be spun into yarns or made into tapes, without post process or external rotation or spinning of the gathered nanotubes. Boron nitride nanotube yarns or tapes of great length can be produced as a result, thereby providing industry with a readily useable format for this type of material. Dopants such as carbon can be added to engineer the band gap of the nanotubes. Catalysts may be formed outside or inside the reactor.

Claims

1-56. -56. (canceled)

57. A continuous boron nitride nanotube yarn having a length greater than 15 cm, the yarn comprising:

a plurality of boron-nitride nanotubes including a first boron-nitride nanotube and a second boron-nitride nanotube, the first and second boron-nitride nanotubes each have an aspect ratio of greater than 10,000;

1 and each forming a helix around a common axis wherein the first and second boron-nitride nanotubes each have a pitch angle between 2° and

50°

.

58. The boron nanotube yarn of claim 57 wherein the pitch angle is between 5°

and 45°

.

59. The boron nanotube yarn of claim 57 wherein the first and second nanotubes each have an aspect ratio of greater than 100,000:

1.

60. A high temperature composite comprising the nanotube yarn of claim 57.

61. Body armor comprising the nanotube yarn of claim 57.

62. A boron nitride composite comprising cubic boron nitride and the boron nitride nanotube yarn of claim 57.

63. A method of producing boron-nitride nanotube continuous yarn, the method comprising:

feeding a boron containing gas species a nitrogen containing gas species, the nitrogen containing gas species and the boron containing gas species being the same or different, a carrier gas, and a catalyst or a catalyst precursor into a plurality of reaction tubes, each reaction tube having a first portion at a first temperature and a second portion at a second temperature greater than the first temperature;

rotating the reaction tubes around a common axis while the boron, nitrogen and catalyst flow from the first portion to the second portion of each of the plurality of reaction tubes;

growing boron-nitride nanotubes towards an end of each of the plurality of reaction tubes; and

combining the boron-nitride nanotubes into a yarn as the nanotubes exit the reaction tubes.

64. The method of claim 63 further comprising at least one of:

gathering the yarn on a bobbin under tension control, wherein the bobbin and tension control is either inside or outside of the reaction chamber;

combining a catalyst precursor with a reducing agent;

adding a dopant to the carrier gas;

growing boron nitride nanotubes in a furnace reactor downstream of the end of the rotating reaction tubes;

gathering boron nitride nanotubes exiting the reaction tubes;

holding the gathered boron nitride nanotubes together; and

allowing the reaction tubes to spin the boron nitride nanotubes into a

65. The method of claim 63 wherein the boron containing gas species and the nitrogen containing gas species are within the same compound or complex.

66. The method of claim 65 wherein the boron and nitrogen containing gas species is selected from at least one of h-BN, c-BN, BH₂NH₃, BN, BNH₆, dimethylamine borane ((CH₃)₂NH.BH₃), the boron ammoniate complex (H₃BNH₃) and borazine (BH)₃(NH)₃.

67. The method of claim 63 wherein the boron containing gas species and the nitrogen containing gas species are different compounds or species and the nitrogen containing gas species is selected from pure nitrogen, ammonia, BH₂NH₃, NaNH₄ and NH₄Cl and the boron containing gas species is selected from B₂H₆, BH₂NH₃, BN, B₂O₂, NaNH₄, or H₃BO3, B₃N₃H₆ and B₁₀H₁₄.

68. The method of claim 63 wherein at least one of:

(a) the carrier gas is selected from helium, nitrogen, argon and ammonia;

(b) the catalyst or catalyst precursor comprises at least one of a transition metal, sulphur and oxygen;

(c) the catalyst or catalyst precursor comprises at least one of iron, nickel or cobalt;

(d) the catalyst precursor comprises an organo-metallic compound, a sulfur containing organic compound, or both;

(e) a first catalyst precursor comprises iron penta-carbonyl or ferrocene and a second catalyst precursor or a catalyst aid precursor comprises at least one of thiophene, nickelocene and cobaltocene;

(f) the catalyst precursor is combined with a reducing agent at a temperature below 25°

C.;

(g) the catalyst is formed by reducing a metallic cation to a metal or metal alloy and the reducing agent is selected from at least one of sodium borohydride, dimethylamine borane, hydrazine or sodium hypophosphate;

(h) a solution of the catalyst precursor is added to a solution of the reducing agent wherein the reducing agent solution is at a temperature of less than or equal to 50°

C.; and

(i) the catalyst is a metallic particle having an average size of less than or equal to 30 nm.

69. The method of claim 63 wherein the catalyst is essentially free of carbon and comprises at least one of a transition metal, two or more metals, iron and at least one of copper, cobalt and nickel.

70. The method of claim 63 wherein at least one of the boron containing gas species, the nitrogen containing gas species and the catalyst precursor is sublimed to reach the vapor phase and are each introduced into the reaction stream without a nebulizer or atomizer.

71. An apparatus for producing boron-nitride nanotubes, the apparatus comprising:

a mixing zone configured to receive catalyst, nitrogen and boron sources;

a plurality of reaction tubes fluidly connected to the mixing zone, the reaction tubes rotationally mounted around a common axis; and

at least one heater constructed and arranged to heat the plurality of reaction tubes.

72. The apparatus of claim 71 wherein the apparatus is fluidly connected to a catalyst source, a nitrogen source, a boron source and a source of a carrier gas.

73. The apparatus of claim 71 wherein the heater is positioned centrally between the plurality of reaction tubes and the mixing zone is heated.

74. The apparatus of claim 71 wherein the apparatus comprises a rotating assembly and a stationary assembly and wherein there is a gastight seal between the rotating assembly and the stationary assembly and the rotating assembly is supported by one or more rotational bearings comprising a ceramic or high temperature bearing.

75. The apparatus of claim 71 comprising a plurality of sublimers wherein the sublimers are in fluid communication with, and upstream of, the mixing zone.

76. The apparatus of claim 71 further comprising a microprocessor, the microprocessor controlling one or more of the rotational speed, the carrier gas flow rate, the temperature of a sublimer, the temperature of a reaction tube or the speed of a take up spool and in response to a change in process parameters, the microprocessor alters at least one of the rotational speed, the carrier gas flow rate, the temperature of a sublimer, the temperature of a reaction tube or the speed of a take up spool.