Electrostatic dissipative composite material
A method of forming an electrostatic dissipative composite material includes preparing a mixture comprising a polyamic acid precursor and a non-carbonaceous resistivity modifier. The polyamic acid precursor reacts to form polyamic acid. The method also includes dehydrating the polyamic acid to form polyimide. The polyimide forms a polymer matrix in which the non-carbonaceous resistivity modifier is dispersed.
1 . A method of forming an electrostatic dissipative composite material, the method comprising:
preparing a mixture comprising a polyamic acid precursor and a non-carbonaceous resistivity modifier, the polyamic acid precursor reacting to form polyamic acid; and
dehydrating the polyamic acid to form polyimide, the polyimide forming a polymer matrix in which the non-carbonaceous resistivity modifier is dispersed.
2 . The method of claim 1 , further comprising adding a second polyamic acid precursor, resulting in the polyamic acid precursor and the second polyamic acid precursor reacting to form polyamic acid.
3 . The method of claim 1 , further comprising mixing the mixture under high shear.
4 . The method of claim 1 , wherein the mixture has a Hegman grind gauge value not greater than 1 micron.
5 . The method of claim 1 , wherein the non-carbonaceous resistivity modifier includes a metal oxide, a metal carbide, a metal nitride, a metal boride, or a metal sulfide.
6 . The method of claim 5 , wherein the non-carbonaceous resistivity modifier includes a metal oxide.
7 . The method of claim 6 , wherein the metal oxide comprises an oxide of iron.
8 . The method of claim 6 , wherein the metal oxide comprises an oxide of copper.
9 . The method of claim 1 , further comprising milling the non-carbonaceous resistivity modifier.
10 . The method of claim 9 , wherein milling the non-carbonaceous resistivity modifier includes milling the non-carbonaceous resistivity modifier prior to preparing the mixture.
11 .- 20 . (canceled)
21 . A composite material comprising a polyimide matrix and a non-carbonaceous resistivity modifier, the composite material having a coefficient of thermal expansion not greater than about 30 ppm/° C. and having a surface resistivity of about 1.0×10 5 ohm/sq to about 1.0×10 13 ohm/sq.
22 . The composite material of claim 21 , wherein the non-carbonaceous resistivity modifier is selected from the group consisting of NiO, FeO, MnO, Co 2 O 3 , Cr 2 O 3 , CuO, Cu 2 O, Fe 2 O 3 , Ga 2 O 3 , In 2 O 3 , GeO 2 , MnO 2 , TiO 2-x , RuO 2 , Rh 2 O 3 , V 2 O 3 , Nb 2 O 5 , Ta 2 O 5 , WO 3 , SnO 2 , ZnO, CeO 2 , TiO 2-x , ITO (indium-tin oxide), MgTiO 3 , CaTiO 3 , BaTiO 3 , SrTiO 3 , LaCrO 3 , LaFeO 3 , LaMnO 3 , YMnO 3 , MgTiO 3 F, FeTiO 3 , SrSnO 3 , CaSnO 3 , LiNbO 3 , Fe 3 O 4 , MgFe 2 O 4 , MnFe 2 O 4 , CoFe 2 O 4 , NiFe 2 O 4 ZnFe 2 O 4 , Fe 2 O 4 , CoFe 2 O 4 , FeAl 2 O 4 , MnAl 2 O 4 , ZnAl 2 O 4 , ZnLa 2 O 4 , FeAl 2 O 4 , MgIn 2 O 4 , MnIn 2 O 4 , FeCr 2 O 4 , NiCr 2 O 4 , ZnGa 2 O 4 , LaTaO 4 , NdTaO 4 , BaFe 12 O 19 , 3Y 2 O 3 .5Fe 2 O 3 , Bi 2 Ru 2 O 7 , B 4 C, SiC, TiC, Ti(CN), Cr 4 C, VC, ZrC, TaC, WC, Si 3 N 4 , TiN, Ti(ON), ZrN, HfN, TiB 2 , ZrB 2 , CaB 6 , LaB 6 , NbB 2 , MoSi 2 , ZnS, Doped-Si, doped SiGe, III-V, II-VI semiconductors, and a mixture thereof.
23 . The composite material of claim 22 , wherein the non-carbonaceous resistivity modifier is selected from the group consisting of NiO, FeO, MnO, Co 2 O 3 , Cr 2 O 3 , CuO, Cu 2 O, Fe 2 O 3 , Ga 2 O 3 , In 2 O 3 , GeO 2 , MnO 2 , TiO 2-x , RuO 2 , Rh 2 O 3 , V 2 O 3 , Nb 2 O 5 , Ta 2 O 5 , and WO 3 .
24 .- 32 . (canceled)
33 . The composite material of claim 22 , wherein the non-carbonaceous resistivity modifier includes a carbide material.
34 .- 35 . (canceled)
36 . The composite material of claim 22 , wherein the non-carbonaceous resistivity modifier includes a nitride material.
37 . (canceled)
38 . The composite material of claim 22 , wherein the non-carbonaceous resistivity modifier includes a boride.
39 .- 43 . (canceled)
44 . The composite material of claim 22 , wherein the non-carbonaceous resistivity modifier includes an oxide of iron.
45 . The composite material of claim 22 , wherein the non-carbonaceous resistivity modifier includes an oxide of copper.
46 . The composite material of claim 21 , wherein the composite material comprises at least about 20 wt % of the non-carbonaceous resistivity modifier.
47 . The composite material of claim 46 , wherein the composite material comprises at least about 55 wt % of the non-carbonaceous resistivity modifier.
48 .- 51 . (canceled)
52 . The composite material of claim 21 , wherein the non-carbonaceous resistivity modifier has a volume resistivity of about 1.0×10 −2 ohm cm to about 1.0×10 7 ohm cm.
53 .- 54 . (canceled)
55 . The composite material of claim 21 , wherein the composite material exhibits a decay time not greater than about 0.5 seconds.
56 .- 57 . (canceled)
58 . The composite material of claim 21 , wherein the surface resistivity is about 1.0×10 5 ohm/sq to about 1.0×10 9 ohm/sq.
59 .- 68 . (canceled)
69 . The composite material of claim 21 , wherein the coefficient of thermal expansion is not greater than about 25 ppm/° C.
70 .- 72 . (canceled)
73 . The composite material of claim 21 , wherein the polyimide comprises the imidized product of pyromellitic dianhydride and oxydianiline.
74 .- 97 . (canceled)
98 . A composite material comprising a polyimide matrix and at least about 65 wt % particulate iron oxide, the polyimide matrix formed of the imidized product of pyromellitic dianhydride and oxydianiline, the composite material having a coefficient of thermal expansion not greater than about 30 ppm/° C. and having a surface resistivity of about 1.0×10 5 ohm/sq to about 1.0×10 13 ohm/sq.
99 . (Canceled)