Methods of preparing polymer nanocomposites
Methods of forming nanocomposites comprising a polymer and metal nanoparticles are disclosed. The nanoparticles are disposed within a matrix of the polymer. In particular, the nanoparticles are formed in situ in an extruder. The methods comprise providing a reaction mixture comprising a polymer, a metal precursor, and a solvent and extruding the reaction mixture to form a polymer nanocomposite. The methods overcome nanoparticle dispersion issues arising from melt blending processes.
1. A method for producing a dispersion containing a polymer and nanoparticles, comprising:
providing a solution comprising a metal precursor and a solvent, wherein the metal precursor is not in the form of nanoparticles;
combining the solution with a polymer to form a mixture; and
extruding the mixture to form the dispersion;
wherein the extrusion step occurs at a melt temperature above the degradation temperature of the metal precursor and wherein the mixture has a residence time of at least 35 seconds;
wherein the solution comprises from about 1 to about 30 wt % of the total weight of the polymer and the solution;
wherein the dispersion contains metal nanoparticles, metal oxide nanoparticles, or a combination thereof;
wherein the nanoparticles have an interparticle distance of from 0.1 nm to about 1500 nm in the dispersion; and
wherein the nanoparticles comprise from about 0.125 to about 5 wt % of the total weight of the nanoparticles and the polymer.
2. The method of claim 1 , wherein the dispersion further comprises a stabilizer to.
3. The method of claim 2 , wherein the stabilizer is added to the mixture.
4. The method of claim 1 , wherein the metal precursor is a metal salt.
5. The method of claim 1 , wherein the solvent is water.
6. The method of claim 1 , further comprising: providing an additive to the dispersion.
7. The method of claim 6 , wherein the additive is added prior to, during, or after the extrusion of the dispersion.
8. The method of claim 6 , wherein the additive is a stabilizer.
9. The method of claim 1 , wherein the nanoparticles in the dispersion comprise from about 0.125 to about 2 wt % of the total weight of the nanoparticles and the polymer.
10. The method of claim 1 , wherein the nanoparticles in the dispersion comprise about 0.125 wt %, about 0.25 wt %, about 0.5 wt %, about 1 wt %, or about 2 wt % of the total weight of the nanoparticles and the polymer.
11. The method of claim 1 , wherein the metal precursor contains zinc or silver, wherein the extrusion step occurs at a melt temperature of at least 150° C., and wherein the nanoparticles in the dispersion comprise from about 0.125 to about 2 wt % of the total weight of the nanoparticles and the polymer.
12. The method of claim 1 , wherein the extrusion step utilizes a twin screw extruder.
13. The method of claim 1 , wherein the metal precursor contains zinc or silver.
14. The method of claim 1 , wherein the metal precursor contains a Group 11 element, Group 12 element, or a transition metal.
15. A molded article comprising the dispersion produced by the method of claim 1 .
16. The molded article of claim 15 , wherein the dispersion contains silver and/or zinc.
17. An article of manufacture comprising the dispersion produced by the method of claim 1 .
18. A method for producing a dispersion containing a polymer and nanoparticles, comprising:
providing a solution comprising a metal precursor and a solvent, wherein the metal precursor is not in the form of nanoparticles;
combining the solution with a polymer to form a mixture; and
extruding the mixture at a melt temperature above the degradation temperature of the metal precursor and wherein the mixture has a residence time sufficient to form the dispersion;
wherein the solution comprises from about 1 to about 30 wt % of the total weight of the polymer and the solution;
wherein the dispersion contains metal nanoparticles, metal oxide nanoparticles, or a combination thereof;
wherein the nanoparticles have an interparticle distance of from 0.1 nm to about 1500 nm in the dispersion; and
wherein the nanoparticles comprise from about 0.125 to about 5 wt % of the total weight of the nanoparticles and the polymer.