Compositions and methods for producing high strength composites
The present invention relates to compositions and methods for producing high strength composites. In one embodiment, a polymer matrix and a naturally-occurring inorganic material are melt processed to produce a high strength composite. In a preferred embodiment, the naturally-occurring inorganic material is volcanic ash. High strength composites of this invention have particular utility as building materials and automotive components.
1. A composition comprising:
(a) a thermoplastic matrix,
(b) volcanic ash, and
(c) a coupling agent, wherein the composition upon melt processing exhibits a flexural modulus of greater than 2000 MPa, a coefficient of thermal expansion of less than 70 μm/m and a density from 0.65 to 0.90 g/cm 3 .
2. The composition of claim 1 wherein the volcanic ash is expanded volcanic ash or unexpanded volcanic ash.
3. The composition of claim 1 , wherein the thermoplastic matrix is high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polyolefin copolymers, polystyrene, polystyrene copolymers, polyacrylates, polymethacrylates, polyesters, polyvinylchloride, fluoropolymers, liquid crystal polymers, polyamides, polyether imides, polyphenylene sulfides, polysulfones, polyacetals, polycarbonates, polyphenylene oxides, polyurethanes, thermoplastic elastomers, epoxies, alkyds, melamines, phenolics, ureas, vinyl esters or combinations thereof.
4. The composition of claim 1 further comprising a blowing agent.
5. The composition of claim 1 wherein the volcanic ash has an average Length:Diameter aspect ration of at least 4:1.
6. The composition of claim 1 further comprising a cellulosic filler.
7. The composition of claim 1 , further comprising one or more of antioxidants, light stabilizer, fibers, blowing agents, foaming agents, antiblocking agents, heat stabilizers, impact modifiers, biocides, compatibilizers, flame retardants, plasticizers, tackifiers, colorants, processing aids, lubricants, coupling agents, and pigments.
8. The composition of claim 1 , further comprising an impact modifier.
9. A method of forming a composite, comprising melt processing a thermoplastic matrix, volcanic ash, and a coupling agent, wherein the melt processed composition exhibits a flexural modulus of greater than 2000 MPa, a coefficient of thermal expansion of less than 70 m/m and a density from 0.65 to 0.90 g/cm 3 .
10. The method of claim 9 , wherein the melt processing includes extrusion, injection molding, batch mixing, blow molding or rotomolding.
11. The method of claim 9 , further comprising a blowing agent.
12. An article comprising a thermoplastic matrix, volcanic ash, and a coupling agent and wherein the article exhibits a flexural modulus of greater than 2000 MPa, a coefficient of thermal expansion of less than 70 μm/m and a density from 0.65 to 0.90 g/cm 3 .
13. The article of claim 12 , wherein the article is a sheet, concrete form, railroad tie, building material or an automotive component.