# US 11,898,021 B2 · Polymeric composites with tunable properties > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,898,021 B2 - Document ID: US11898021B2 - Status: Granted - Kind: B2 - Application number: 16/733,462 - Filed: 2020-01-03 - Published: 2020-07-09 - Granted: 2024-02-13 - Earliest claimed: 2019-01-04 - Assignees: Syracuse University - Applicants: Wanliang Shan - Inventors: Wanliang Shan - Web page: https://patentgrep.com/patent/US11898021B2 ## CPC - C08J 9/0085: {Use of fibrous compounding ingredients (C08J9/0076 takes precedence)} - B29B 7/90: Fillers or reinforcements {, e.g. fibres} - B29C 70/68: by incorporating or moulding on preformed parts, e.g. inserts or layers {, e.g. foam blocks (mould constructions therefor B29C33/12; joining preformed parts by moulding B29C65/70)} - C08J 9/0066: {Use of inorganic compounding ingredients} - C08J 9/009: {Use of pretreated compounding ingredients} - C08K 3/04: Carbon - C08K 3/08: Metals - C08K 7/06: Elements - C08K 9/02: Ingredients treated with inorganic substances - C08K 9/10: Encapsulated ingredients - B29K 2083/00: Use of polymers having silicon, with or without sulfur, nitrogen, oxygen, or carbon only, in the main chain, as moulding material - B29K 2307/04: Carbon - B29K 2505/00: Use of metals, their alloys or their compounds, as filler - B29K 2705/10: Copper - C08J 2203/06: CO2, N2 or noble gases - C08J 2300/26: Elastomers - C08J 2383/04: Polysiloxanes - C08K 2003/0862: {Nickel} - C08K 2201/001: Conductive additives - C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29) - B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS ## Abstract A variety of polymeric composites with tunable mechanical stiffness and electrical conductivity are claimed herein. For example, the composite may have an elastomeric matrix, a plurality of tunable particles, and a plurality of conductive fibers embedded in the matrix. The composites may also be a tunable foam matrix and an elastomeric matrix. In some embodiments, the composites are a low melting point alloy (LMPA) foam infiltrated by an elastomer, whose stiffness can be tuned by more than two orders of magnitude through external heating. In other embodiments, the composite may be a conductive particle-fiber-matrix three-component composite capable of changing its elastic rigidity rapidly and reversibly when powered with electrical current. ## Claims ### Claim 1 A composite material having a tunable stiffness, comprising: an elastomeric matrix having an elastic modulus between 10 kPa and 1 MPa; a metallic component combined with the matrix, wherein the metallic component comprises a plurality of metal alloy particles having a diameter between 5 and 50 micrometers and a melting point that is above room temperature and no more than 62 degrees Celsius; a plurality of conductive fibers combined with the matrix and forming a percolative network with the metallic component; and wherein the composite material has a first Young's modulus at room temperature and a second Young's modulus when heated above the melting point of the plurality of metal alloy particles by an application of electrical energy to the composite material such that a ratio of the first Young's modulus to the second Young's modulus is between 4.33 and 5.05 inclusively. ### Claim 2 (depends on 1) The composite material of claim 1, wherein the metal alloy comprises Field's metal. ### Claim 3 (depends on 1) The composite material of claim 1, wherein the plurality of conductive fibers are formed from nickel coated carbon fibers. ### Claim 4 (depends on 1) The composite material of claim 1, wherein the elastomeric matrix is polydimethylsiloxane. ### Claim 5 (depends on 1) The composite material of claim 1, wherein the elastomeric matrix comprises an elastomeric foam. ### Claim 6 (depends on 5) The composite material of claim 5, wherein the metallic component comprises a metallic foam. ### Claim 7 (depends on 6) The composite material of claim 6, wherein the elastomeric foam and the metallic foam form a bicontinuous network. ### Claim 8 (depends on 7) The composite material of claim 7, wherein the elastomeric foam is formed from polydimethylsiloxane. ### Claim 9 (depends on 8) The composite material of claim 8, wherein the metallic foam comprises includes a bismuth alloy. ### Claim 10 (depends on 1) The composite material of claim 1, wherein the elastomeric matrix is present in a volume fraction of between 45 and 60 percent, the metallic component is present in a volume fraction of between 29 and 45.9 percent, and the plurality of conductive fibers are present in a volume fraction of between 8.2 and 11.4 percent.