Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/02—Layer formed of wires, e.g. mesh
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
  • B32B5/32—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed at least two layers being foamed and next to each other
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
  • B32B5/18—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by features of a layer of foamed material
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/162—Selection of materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
  • B32B2260/02—Composition of the impregnated, bonded or embedded layer
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
  • B32B2260/04—Impregnation, embedding, or binder material
  • B32B2260/046—Synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2266/00—Composition of foam
  • B32B2266/06—Open cell foam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/10—Properties of the layers or laminate having particular acoustical properties
  • B32B2307/102—Insulating
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2311/00—Metals, their alloys or their compounds
  • B32B2311/12—Copper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2311/00—Metals, their alloys or their compounds
  • B32B2311/20—Zinc
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B2311/00—Metals, their alloys or their compounds
  • B32B2311/24—Aluminium
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B2001/742—Use of special materials; Materials having special structures or shape
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
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  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12007—Component of composite having metal continuous phase interengaged with nonmetal continuous phase
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12021—All metal or with adjacent metals having metal particles having composition or density gradient or differential porosity
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12014—All metal or with adjacent metals having metal particles
  • Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
  • Y10T428/12042—Porous component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
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  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12479—Porous [e.g., foamed, spongy, cracked, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
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  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12556—Organic component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12736—Al-base component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/249955—Void-containing component partially impregnated with adjacent component
  • Y10T428/249956—Void-containing component is inorganic
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/249961—With gradual property change within a component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/249967—Inorganic matrix in void-containing component
  • Y10T428/24997—Of metal-containing material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/249987—With nonvoid component of specified composition
  • Y10T428/249991—Synthetic resin or natural rubbers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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  • Y10T428/249991—Synthetic resin or natural rubbers
  • Y10T428/249992—Linear or thermoplastic

Definitions

• the present invention relates generally to metal composites and more particularly to metal/polymer composites.
• Fig. 1 shows the acoustic damping behavior of an aluminum alloy foam/phthalonitrile composite, heat treated under the various condition described in the accompanying Example
• Fig. 2, Fig. 3 and Fig. 4 show the results of damping measurements for a copper foam/phthalonitrile composite, over a frequency range of 0.1 to 10 Hz.
• Fig. 5, Fig. 6, and Fig. 7 show the damping behavior of a titanium foam phthalonitrile composite under different heat treatment conditions as described in Example 5.
• Fig. 8 and Fig. 9 show the damping behavior of a zinc foam/phthalonitrile composite under different heat treatment conditions as described in Example 5.
• Fig. 10 is a graph showing the Tan ⁇ over a frequency range of 0.1 to 10 Hz for various polymers and metal foams.
• Fig. 11 shows the damping behavior of a white rubber/aluminum alloy foam over the frequency range of 0.1 to 10 Hz.
• Fig. 12 shows the damping behavior of a red rubber/aluminum alloy foam over the frequency range of 0.1 to 10 Hz.
• Fig. 13 shows the damping behavior of an epoxy /aluminum alloy foam over the frequency range of 0.1 to 10 Hz.
• Fig. 14 shows the damping behavior of an acrylic polymer/aluminum alloy foam over the frequency range of 0.1 to 10 Hz.
• Fig. 15 shows the stress/strain diagram for an aluminum alloy foam/phthalonitrile composite that was heat treated at 280 °C for 18 hours, at 325 °C for 4 hours, and at 375 °C for 4 hours.
• Fig. 16 shows the stress/strain diagram for an aluminum alloy foam/acrylic composite.
• the metal foam of the present invention may be any porous metal workpiece, particularly a metal foam, regardless of shape or percent density, having an open cell structure that permits impregnation with an uncured polymer.
• Particularly useful metals include aluminum, titanium, nickel, copper, iron, zinc, lead, silver, gold, platinum, tantalum, and alloys (including steel) based on these metals. Other metals may also be used. Aluminum and titanium and alloys thereof are particularly useful because of their low density.
• Metal foams may be produced by a variety of known methods. For example, a molten metal may be placed under high pressure so that it dissolves a non-reactive gas. When the pressure is released and the metal is allowed to cool, the dissolved gas escapes and leaves open-celled pores in the metal body. In other processes, foaming agents are added to molten metal. Another process mixes monomers with metal particles and heats the mixture to induce foaming and solidification of the resin. As used herein, the term “resin” encompasses prepolymers, monomers, and mixtures thereof. A "cured resin” is the cured polymer. With further heating, the metal particles consolidate and the polymer hydrolyzes. United States Patent No. 4,569,821, the entirety of which is incorporated herein by reference for all purposes, improves upon that process by substituting a stabilized hydrogel for the monomers, allowing more complete pyro lysis of the organic components during formation of the metal foam.
• Percent foam density and pore size also determine the number of polymer/metal interfaces that an acoustic vibration must traverse. As explained below, the polymer/metal interfaces contribute mainly to the sound damping capabilities of the composites of the present invention.
• a typical useful pore size is 5-100 pores/inch. More often, a pore size of about 10-50 pores/inch is used, and most often a pore size of about 10-40 pores/inch is used.
• the percent foam density is about 5- 40. More often, the percent foam density is about 8-10.
• the pores (also refe ⁇ ed to in the present specification and claims as "cells") within the metal foam have a locally uniform size and distribution.
• a foam has a locally uniform size and distribution of pores if most of the pores of the foam are surrounded by evenly distributed pores having approximately the same void diameter as the surrounded pore. Local non-uniformity in the size or distribution of the pores within the metal foam decreases the ability to predict the characteristics of the resulting composite.
• the metal foam may be divided into regions of different pore size, or may have a gradation of pores sizes in any direction along the metal foam, while maintaining locally uniform pore size, without harming the predictability of performance.
• the metal foam may be impregnated by any available method. Typically, the metal foam is impregnated by contacting it with a resin component.
• the resin component may be a neat resin or a neat blend of resins, or may include any catalysts, curing agents, or additives desired.
• the resin component may be a powder (of sufficiently small particle size to penetrate the pores of the metal foam), a melt, a room temperature liquid, or a solution, and may include mixtures of several prepolymers and/or monomers.
• a vacuum or positive pressure may be applied to assist the penetration of the resin component into the metal foam. Solvent, if present, is removed by evaporation.
• the resin component is then converted (solidified or consolidated by any method, typically heating to polymerize and/or cure the resin, or cooling to solidify a molten resin) to a solid bulk polymer (partially crosslinked, fully crosslinked, or non-crosslinked) that fills or partially fills the open-cells of the metal foam.
• the viscosity of the resin component i.e., the impregnant
• the impregnant viscosity should be selected to allow the metal foam to be completely impregnated with the resin component under practical processing conditions.
• a high impregnant viscosity may restrict the ability of the resin component to completely penetrate the open porous structure of the metal foam. This problem may be overcome by forcing, under positive pressure, the resin component into the pores of the foam.
• an appropriate impregnant viscosity may be selected empirically, without undue experimentation, given the guidance provided by this specification and the accompanying examples.
• Resin component in powder form can be forced into the pores of the metal foam by any method.
• the powdered resin component may be poured on top of the metal foam, and positive or negative pressure may be applied to the powder, forcing it into the pores of the foam.
• the metal foam may be vibrated to aid in impregnation.
• the polymeric component of the present invention is typically selected to have high intrinsic acoustic damping. Basically, the acoustic damping ability of a polymer is determined by its dynamic modulus at a given frequency. In the case of rubber materials, the acoustic damping ability of unhardened rubbers is significantly greater than that of hardened or fully hardened rubbers. In general, thermoplastics and thermosets, unlike elastomers, provide excellent results when used according to the presently claimed invention, whether cured or uncured.
• Polymers particularly useful in the present invention include phthalonitriles, epoxies, acrylics, silicones, polyurethanes, polyimides, polyvinyls, polycarbonates, natural rubbers, synthetic rubbers, phenolics, polyolefins, polyamides, polyesters, fluoropolymers, poly(phenylene ether ketones), poly(phenylene ether sulfones), poly(phenylene sulfides) and melamine-formaldehyde resins.
• the acoustic damping capabilities of the composite of the present invention arise in part from the acoustic properties of the polymerized resin component and in part from dissipation of energy at the polymer/metal interface. Energy is never transferred without loss at interfaces between different materials. Therefore, as the number of interfaces that an acoustic vibration must traverse increases, the percentage of dissipated acoustic energy also increases.
• a metal foam/polymer composite provides numerous interfaces between the polymer and the metal matrix.
• the acoustic damping properties of a polymer/metal matrix composite may be improved, in some cases, by forming the composite under conditions that avoid or minimize chemical or bonding between the metal and the polymer component. Bonding between the polymeric component and the interface may be controlled by the combination of metal and polymeric agent selected, the choice of curing agent and/or curing mechanism, and the application of a release agent, if any, to the metal foam before impregnation with resin component. In other cases, however, vibration of a bond between a metal foam and a polymer may be a loss mechanism that increases acoustical damping across the desired frequency range.
• the composite of the present invention should provide a sufficient number of polymer/metal interfaces to allow good acoustic damping.
• the smallest dimension of the metal foam is usually at least about 1.5 times the average void diameter of the metal foam. In many cases, for acoustic damping applications, the smallest dimension of the metal foam will be three or more times greater than the average void diameter of the metal foam.
• acoustic damping in these materials might be further improved by the inclusion of polymer/gas and/or gas/metal interfaces, which further increase the number of interfaces that an acoustic vibration must traverse through the composite.
• polymer/gas and/or gas/metal interfaces may be formed by many mechanisms, such as the use of a foamed resin component to produce the polymeric component of the composite, the dissolution of the neat resin or blend of resins in a solvent before impregnation, or the inclusion of minute amounts of gas, or materials that form a gas or a vapor during curing, within the resin component used to form the polymeric component.
• the amount of gas or gas forming materials should be sufficient to significantly enhance the acoustic damping capabilities of the composite, but should not provide sufficient gas to essentially destroy the structural integrity of the composite and/or the polymeric component thereof.
• the optimum amount of any gas or gas producing agent used in the resin component will vary depending upon the desired use for the composite and may be empirically determined without undue experimentation.
• Composites according to the present invention may be constructed to exhibit acoustic damping across a frequency band residing within a range of typically about 0.001-80 kHz.
• the precise frequency band, as well as the bandwidth over which a composite according to the present invention exhibits acoustic damping, is determined by the selected polymer, metal, pore size and percent foam density.
• the frequency range of damping may be extending by stacking together metal foam/polymer composites having different pore sizes, percent metal foam densities, polymers and/or metals.
• Pore size and percent metal foam density may also be varied, without stacking, by providing a metal foam having regions of different average pore size or having an average pore size that is graded in one or more directions. It may also be possible to vary the polymer used within a single sheet.
• a foam may be impregnated with a first resin component.
• the resin component- impregnated foam may then be subjected to pressure on, for example its upper surface, to force any portion of the first resin component out in the upper portion of the metal foam down into the lower portion.
• the resin component-impregnated foam may then be solidified while under this positive pressure.
• the upper portion of the metal foam may be impregnated with a second resin component.
• components manufactured using composites according to the present invention may alter the noise properties of machinery, aerospace vehicles, domestic vehicles, military vehicles, commercial vehicles, marine vehicles and maritime vehicles.
• composites according to the present invention are readily manufactured, for example, by resin transfer molding (RTM), resin infusion molding, or resin injection molding.
• Phthalonitrile monomer 4,4'-bis(3,4-dicyanophenoxy)biphenyl, was purchased from Daychem Laboratories. 10 g of the monomer was placed in an aluminum planchet and melted on a hot plate at 250 °C (monomer melts around 235 °C). The monomer melt was degassed for about 2h to eliminate trace amounts of solvent present. The phthalonitrile prepolymer was synthesized by adding 0.15- 0.168 g (1.5-1.68 wt%) of l,3-bis(3-aminophenoxy)benzene, obtained from National Starch Corporation, to the monomer melt. The melt was stirred for 15 min. and was used for fabrication of phthalonitrile/metal foam composite specimens.
• Example 2 Fabrication of phthalonitrile/aluminum foam composite
• the mold was then heated in an air circulating oven for 9h at 280 °C and cooled back to room temperature over a 3h span.
• the composite samples made with this prepolymer showed an incomplete penetration of the resin into the metal foam. Therefore, subsequent composite fabrications involved a slower curing prepolymer made with 1.5% curing additive.
• the prepolymer has an initial lower viscosity.
• Example 3 Fabrication of phthalonitrile/aluminum foam composite
• the composite samples made with this prepolymer showed a complete penetration of the resin through the metal foam.
• the mechanical and damping properties of the phthalonitrile/aluminum composite samples were evaluated after heat treatment at the following conditions: (A) 9h at 280°C (B) 18h at 280°C (C) 18h at 280, 4h at 325°C and (D) 18h at 280, 4h at 325,4h at 375 °C. Conditions (C) and (D) employed an inert atmosphere purge of argon.
• Example 5 Fabrication of phthalonitrile/titanium foam composite
• the mechanical and damping properties of the phthalonitrile/titanium composite samples were evaluated after heat treatment at the following conditions: (A) 9h at 280 °C (B) 18h at 280 °C (C) 18h at 280, 4h at 325 °C and (D) 18h at 280, 4h at 325,4h at 375 °C. Conditions (C) and (D) employed an inert atmosphere purge of argon.
• the mechanical and damping properties of the phthalonitrile/zinc composite samples were evaluated after heat treatment at the following conditions : (A) 9h at 280 °C (B) 18h at 280°C (C) 18h at 280, 4h at 325°C and (D) 18h at 280, 4h at 325, 4h at 375°C.
• Example 8 Fabrication of Aluminum Alloy Foam /Red Rubber Composite.
• Example 9 Fabrication of Epoxy /Aluminum Alloy Foam Composite.
• Epon 828 and an aromatic diamine were mixed thoroughly and placed into the aluminum mold.
• the composition was cured by heating at 65 °C for 5-6 hours.
• the epoxy /aluminum foam composite was used for evaluating damping and mechanical properties.
• Example 10 Fabrication of Acrylic/Aluminum Alloy Foam Composite.
• An aluminum mold, 3"x 2" was used for fabrication of composite specimens.
• 18 ml of catalyst B was added to 40 ml of resin A of the EPO-KWICK components and thoroughly mixed.
• the mixture was poured on top of several aluminum foam strips, I "x0.5"x0.185", contained in the aluminum mold.
• a vacuum was applied for 10 minutes to degas and consolidate the dispersion of the composition into the pores of the aluminum foam.
• the composition was cured by keeping at room temperature overnight.
• the acrylic/aluminum alloy foam composite was used for evaluating damping and mechanical properties.
• foams and filler materials For the purpose of demonstration, we have used selected foams and filler materials. Many metals or even high strength alloys can be used as skeleton material and also wide variety of filler materials can be used to design the composite possessing required strength and damping capability. Other factors such as environmental compatibility, temperature and chemical compatibility in addition to cost can dictate the choice of the materials to be used.
• the composites produced in Examples 3-9 were used for damping measurements.
• the samples were prepared with dimensions having 4.5 mm thickness, 10 mm width, and 32 mm length.
• the damping capacity of the samples were measured with a dynamic mechanical thermal analyzer (DMTA).
• DMTA dynamic mechanical thermal analyzer
• a small sinusoidal mechanical stress is applied to the sample and the resulting sinusoidal strain transduced.
• Comparison of the amplitude of the signals yields the complex dynamic modulus E * .
• the phase lag (d) of strain behind stress is measured and the storage modulus and loss factor of the material are calculated.
• Example 3 The aluminum alloy foam/phthalonitrile composite prepared in Example 3 was evaluated for its damping characteristics under 1 Hz frequency. The results of the damping measurements were shown in Fig. 1. The figure shows the damping behavior of the composite under different heat treatment conditions as described in Example 3. The damping measurements are plotted with temperature. It is noted that damping peak locations at a given temperature can be adjusted based on heat treatment of composite. The room temperature damping (flat portion of curve) is also higher than the best damping material such as VacrosilTM as shown in Fig. 10.
• Example 13 Damping Characteristics of Copper Foam Phthalonitrile Composite.
• the copper foam/phthalonitrile composite prepared in Example 4 was evaluated for its damping characteristics under 0.1 to 10 Hz frequency.
• the results of the damping measurements were shown in Fig. 2, Fig. 3, and Fig. 4.
• the figures show the damping behavior of the composite under different heat treatment conditions as described in Example 4.
• the damping measurements are plotted with temperature. It is noted that damping peak locations at a given temperature can be adjusted based on heat treatment of the composite.
• the room temperature damping (flat portion of curve) is also higher than the best damping material such as VacrosilTM as shown in Fig. 10.
• the titanium foam/phthalonitrile composite prepared in Example 5 was evaluated for its damping characteristics under 0.1 to 10 Hz frequency.
• the results of the damping measurements were shown in Fig. 5, Fig.6, and Fig 7.
• the figures show the damping behavior of the composite under different heat treatment conditions as described in Example 5.
• the damping measurements are plotted with temperature. It is noted that damping peak locations at a given temperature can be adjusted based on heat treatment of the composite.
• the room temperature damping (flat portion of curve) is also higher than the best damping material such as VacrosilTM as shown in Fig. 10.
• the zinc foam/phthalonitrile composite prepared in Example 6 was evaluated for its damping characteristics under 0.1 to 10 Hz frequency.
• the results of the damping measurements were shown in Fig. 8 and Fig. 9.
• the figures show the damping behavior of the composite under different heat treatment conditions as described in Example 5.
• the damping measurements are plotted with temperature. It is noted that damping peak locations at a given temperature can be adjusted based on heat treatment of the composite.
• the room temperature damping (flat portion of curve) is also higher than the best damping material such as VacrosilTM as shown in Fig. 10.
• Example 16 Damping Characteristics of Aluminum Alloy Foam/white rubber Composite.
• the aluminum alloy foam/white composite prepared in Example 7 was evaluated for its damping characteristics under 0.1 to 10 Hz frequency. The results of the damping measurements were shown in Fig. 11. This figure shows the damping behavior of the composite. The damping measurements are plotted with temperature. It is noted that damping characteristics are better than the best damping material such as VacrosilTM as shown in Fig. 10.
• Example 17 Damping Characteristics of Aluminum Alloy Foam/red rubber Composite.
• the Aluminum Alloy Foam/red rubber composite prepared in Example 8 was evaluated for its damping characteristics under 0.1 to 10 Hz frequency. The results of the damping measurements were shown in Fig. 12. This figure shows the damping behavior of the composite. The damping measurements are plotted with temperature. It is noted that damping characteristics are better than the best damping material such as VacrosilTM as shown in Fig. 10.
• Example 18 Damping Characteristics of Aluminum Alloy Foam/Epoxy Composite.
• the Aluminum Alloy Foam epoxy composite prepared in Example 8 was evaluated for its damping characteristics under 0.1 to 10 Hz frequency.
• the results of the damping measurements were shown in Fig. 13. This figure shows the damping behavior of the composite.
• the damping measurements are plotted with temperature. It is noted that damping characteristics are better than the best damping material such as VacrosilTM as shown in Fig.
• Example 10 The Aluminum Alloy Foam Acrylic composite prepared in Example 10 was evaluated for its damping characteristics under 0.1 to 10 Hz frequency. The results of the damping measurements were shown in Fig. 14. The figure shows the damping behavior of the composite. The damping measurements are plotted with temperature. It is noted that damping characteristics are better than the best damping material such as VacrosilTM as shown in Fig. 10.
• Example 20 Mechanical Properties of Aluminum Alloy Foam/Phthalonitrile Composite.
• Fig. 15 shows the stress/strain diagram for the composite which was heat treated at 280°C for 18 hours, at 325 °C for 4 hours, and at 375 °C for 4 hours. The figure shows that the composite exhibit superior mechanical properties relative to the cured phthalonitrile resin.
• Example 21 Mechanical Properties of Aluminum Foam/ Aery lie Composite.
• Fig. 16 shows the stress/strain diagram for the composite. The figure shows that the composite exhibit superior mechanical properties relative to the aluminum alloy foam.

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