The present invention relates to development of Conducting Polymer based composite as antistatic shield material for forming packages or for electrostatically sensitive components principally for protecting them from potential damages from electrostatic charges. 5
BACKGROUND AND PRIOR ARTS OF THE INVENTION
[002] Conducting polymers with an extended conjugated system, such as Polythiophene, Polypyrrole or Polyaniline, are known to be widely utilized due to their interesting electrical, optical and chemical characteristics, good thermal and environmental stability, low toxicity, easy polymerization, adjustable electrical 10 conductivity, etc. In addition they can be made from readily available and inexpensive starting materials. The current invention relates the fabrication of Polythiophene-Graphene grafted Carbon fiber composite as an efficient antistatic shield material for electronic components. The damage from electrostatic discharge has become major concern in electronic components and units. 15 Furthermore, Antistatic safety is also required for elements where relative motion between varied materials occurs like weaving machine hands, plane tyres and so on. Martin et al. (2004) have reported that PEDOT/PSS (poly (3,4-ethylenedioxythiophene) polystyrene sulfonate) composite plays an important commercial role in anti-static coatings or conductive coatings in electronic 20 components. Polythiophene based antistatic shield materials can be prepared either by chemical synthesis or it may be electrochemically deposited on the substrate surface. Furthermore, Kusy et al. (1986) observed that antistatic protection is also required for parts where relative motion between dissimilar materials occurs like weaving machine arms, airplane tyres, etc. Conventional 25 polymers commonly being used for packaging of various electronic equipments but due to their inherent electrical insulating nature, these polymers failed to dissipate the static or electrostatic charge. For this the use of conducting blends and composites with traditional polymers as an electrostatic charge dissipative
3
fabric is one of the promising application of conducting polymers which combines the mechanical properties of conventional polymers and electrical properties of conducting polymers.
[003] Following are the works done so far in the field of Conducting Polymers based antistatic shield Materials: 5
[004] WO 2013127500 relates to the fabrication of a layered structure which can be employed in the field of polarization filters, in particular for shielding polarization filters from electrostatic discharge and electromagnetic radiation. The shielding can serve on the one hand to increase the stability of polarization filters and on the other hand to improve the quality of the filters. The patent furthermore 10 relates to a process for the production of a layered structure which can be employed as shielding for polarization filters, and a device having a layered construction according to the patent. The layered structure according to invention comprises cellulose ester as polarizer layer and at least one conductor layer comprising a conductive polymer. The conductive polymer is chosen from the 15 group consisting of a thiophene, a polyacetylene, a polyparaphenylene, a polyaniline and a polypyrrole or a mixture of at least two of these.
[005] US 20100190924 relates to electrically conductive and non-conductive polymer composite materials suitable for use in electrically conductive materials, electromagnetic wave shielding materials, heating elements, antistatic materials, is 20 substitutes for existing polymer composites, and the like. This application also relates to methods of making the electrically conductive and non-conductive polymer composite materials. The conducting polymer composite is the blend of conducting polymer and conducting filler wherein the conducting filler is electro-conductive fillers selected from the group consisting of graphite, carbon black, 25 carbon fiber, carbon nanofiber, carbon nanotubes, intrinsically conducting materials, and mixtures thereof. The patent provides rapid, facile and low-cost methods for making conductive and non-conductive polymer composites, wherein the polymer composites are manufactured by in situ polymerization at room
4
temperature. Within a short period time (preferentially for example, less than 10 minutes) after being administered, the composition forms a network that develops with high strength and functional (for example, electrically conductive) composites. The resulting composites can be molded into any shape and/or size and exhibits excellent mechanical properties. According to one aspect, the 5 invention provides methods for making polymer composites from cyanoacrylate monomers and starches as filler by in situ polymerization. In another aspect, the invention provides methods for making conducting polymer composites from using the polymerized cyanoacrylate-starch polymer composites as a matrix.
[006] US 20150284141 relates to multi-layered materials as anti-static shield 10 comprising an electrically conductive layer and a support layer. This invention relates to anti-static materials which protect devices which are sensitive to electrostatic discharge and/or shock. The electrically conductive layer consists of an electrically conductive polymer or an electrically conductive polymer composite. The conjugated conductive polymer used for making electrically 15 conductive layer comprises poly(phenylenevinylenes), polyfluorenes, poly(spirobifluorenes), polythiophenes, poly(p-phenylenes), poly(anilines), poly(pyrroles), copolymers thereof, or mixtures thereof.
[007] EP 0554588 relates to a sheet or web material having antistatic properties. A sheet material is developed that comprising of a hydrophobic resin support or 20 paper support coated with at least one hydrophobic resin layer wherein said resin support or resin layer is coated with a transparent antistatic layer containing as an essential component an oxidatively polymerized polythiophene with conjugated polymer backbone in the presence of a polymeric polyanion compound. The antistatic layer is coated with an overlying adhering barrier layer applied from 25 aqueous polymer dispersion, i. e. polymer latex, wherein said polymer has hydrophilic functionality sufficient to render said overlying layer adherent to a thereon coated hydrophilic colloid-containing layer.
5
OBJECTS OF THE INVENTION:
[008] The primary objective of the present invention is development of Conducting Polymer-Graphene grafted carbon fiber as antistatic shield material for electronic components, chip carriers, electrostatically sensitive components and protecting them from potentially damages from electrostatic charges. 5
[009] Another objective of the invention to design conducting polymer composite incorporating filler materials and by selecting a medium of synthesis of prepared composite.
SUMMARY OF THE INVENTION
[0010] The present invention provides a process of synthesizing conducting 10 polymers with a filler material coated over a carbon fiber substrate in aqueous medium. The method comprising synthesizing Polythiophene with graphene as filler deposited over carbon fiber substrate, SDS and APS used as dopant and oxidant during the oxidative polymerization of thiophene monomer, testing the antistatic properties by John Chubb Instrument (JCI 155 v5) charge decay test 15 unit, and antistatic performance of prepared composite (50 x 70 mm2 Dimensions) by measuring the time on applying the positive as well as negative high corona voltage of 5000 V on the surface of material to be tested and recorded the decay time at 10 % cutoff. Investigation is performed for the anti-static behaviour of blank carbon fibre, polythiophene and polythiophene-graphene grafted carbon 20 fiber composites. The polythiophene and polythiophene-graphene grafted carbon fiber composites showed static decay time in the order of 0.2–0.5 sec at 10% cut-off. Based on the obtained results, it may be concluded that polythiophene and polythiophene-graphene grafted over carbon substrate can be utilized as effective shield materials for static charge. 25
[0011] The product part constitutes a polymer-graphene grafted carbon fiber composite as an antistatic protection shield material, said composite comprising
6
thiophene monomer, grapheme as filler material, and carbon fiber as substrate wherein thiophene (Th) monomer is polymerized to yield polythiophene (PTh).
[0012] The process part for preparing polymer-graphene grafted carbon fiber composite as an antistatic protection shield material, said process comprising the steps of using blank carbon fibre as antistatic shield material; synthesising SDS 5 doped PTh grafted on carbon fibre by in situ chemical oxidative polymerization of PTh in the presence of APS (ammonium per sulphate) as an oxidant; synthesising SDS doped PTh grafted with graphene decorated on carbon fiber; and further evaluation of performance of said SDS doped PTh grafted with graphene decorated carbon fiber. Further evaluation of performance of PTh-graphene 10 deposited carbon fiber composite shows the least anti-static decay time of 0.2 (s) while PTh-deposited carbon fibre composite shows 0.4 (s) for 10 % criterion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the drawings accompanying this specification:-
[0014] Fig. 1: Schematic of the synthesis of Polythiophene-Graphene grafted 15 carbon fiber composite by chemical oxidative polymerization process.
[0015] Fig. 2: XRD pattern of (a) Carbon fiber (b) PTh-CF composite and (c) PTh-CF-Graphene Composite
[0016] Fig. 3: FE-SEM images of (a) bare carbon fiber (b) PTh grafted on carbon fiber (c) PTh-Graphene composite grafted on carbon fiber 20
[0017] Fig. 4: Antistatic results of (a) Carbon Fiber (b) CF-PTh (c) CF-PTh-Graphene composite
DETAILED DESCRIPTION OF THE INVENTION
[0018] At the very outset of the detailed description, it may be understood that the ensuing description only illustrates a particular form of this invention. However, 25 such a particular form is only exemplary embodiment, and without intending to imply any limitation on the scope of this invention. Accordingly, the description
7
is to be understood as an exemplary embodiment and teaching of invention and not intended to be taken restrictively.
Materials and Reagents Used:
[0019] Thiophene (99% Sigma-Aldrich) was purified by distillation at reduced pressure and stored in a refrigerator before use. Sodium dodecyl sulfonate (SDS) 5 (Merck chemicals, India) used as a dopant, Ammonium per sulphate (APS) (Merck chemicals, India) used as oxidant and hydroxyl peroxide (H2O2, 30% solution) (Merck chemicals, India) used as a co-oxidant. Acetone, methanol, and chloroform are all analytical grade reagents purchased from Rankem Limited, India, and were used as received. Graphene (XG Sciences, United States) was 10 used as such without any purification. Double deionized water (specific resistivity of 106 Ω cm) was used to prepare aqueous solutions. Carbon fibre felt (3DTorayca T-300 carbon fibres 3D structure) purchased from Toray, USA.
[0020] The present invention describes a process for synthesizing Polythiophene 15 with Graphene by using SDS as dopant, APS as oxidant and carbon fiber as substrate in an aqueous medium. The method comprises synthesizing Polythiophene with graphene as filler deposited over carbon fiber substrate wherein SDS and APS used as dopant and oxidant during the oxidative polymerization of thiophene monomer, then testing the antistatic properties by 20 John Chubb Instrument (JCI 155 v5) charge decay test unit. Antistatic performance of prepared composite (50 x 70 mm2 dimensions) by measuring the time on applying the positive as well as negative high corona voltage of 5000 V on the surface of material to be tested and recorded the decay time at 10 % cutoff. The polymer chosen for deposition over carbon fiber substrate is Polythiophene 25 and the like. The medium of polymerisation was aqueous i.e. deionised water used as solvent and the like. The dopant and oxidant chosen was Sodium dodecyl sulphate (SDS) and ammonium per sulphate (APS) during the polymerization of monomer thiophene and the like. The monomer thiophene encapsulated with
8
graphene and deposited over carbon fiber substrate. The prepared samples tested by John Chubb Instrument (JCI 155 v5) charge decay test unit. The antistatic performance of prepared composite (50 x 70 mm
2 Dimensions) evaluated by measuring the decay time on applying the positive as well as negative high corona voltage of 5000 V on the surface of material to be tested and recorded the decay 5 time at 10 % cutoff.
[0021] The PTh coated carbon fiber was prepared by in-situ chemical oxidative polymerization of PTh in the presence of APS. Initially, we have taken 0.05 – 0.2 M Thiophene monomer and 0.05 – 0.2 M SDS used as dopant was taken in a beaker and then homogenized at 10,000 – 15,000 rpm for 2 hrs in ultrasonicator to 10 form a stable emulsion. After homogenization, the carbon fiber used as substrate cut with the dimension of 50 mm × 70 mm on which coating will perform is put into the emulsion of above prepared mixture and allowed to soak with the emulsion. After those 0.05 – 0.2 M APS taken into the burette and was added drop wise to the solution with continuous shaking on a rotary shaker by providing 0-5 ̊ 15 C temperature to the reaction by placing large ice cubes around the rotary shaker for 12-48 hrs. Ultrasonication is done on the whole solution for 4-8 hrs. After that, PTh decorated carbon fiber was obtained which is then washed with de-ionized water and then dried in vacuum oven for 12-48 hrs at 30-70 ºC.
[0022] For the preparation of Polythiophene grafted graphene deposited over 20 carbon fiber felt substrate, the protocol used at the first Step is to take 0.05 – 0.2 M Thiophene monomer and 0.05 – 0.2 M Sodium dodecyl Sulphate (SDS) solution was taken in beaker and then homogenized at 10000 - 15000 rpm for 1-3 hrs to form a stable emulsion. In second step, the carbon fiber with dimensions 50 mm × 70 mm is put into the emulsion solution. In third step, 0.05 – 0.2 gm 25 graphene is added into the above prepared mixture with carbon fiber. Then, 0.05 – 0.2 M APS solution act as oxidant for polymerisation reaction is taken in a burette and added drop wise to the above prepared solution with continuously shaking on a rotary shaker by providing 0-5 ºC temperature to the reaction by placing large
9
ice cubes. Then after continuous shaking up to 6hrs prepared sample was filtered, washed and dried in oven at 30-70 °C.
Embodiments
[0023] In one embodiment of the invention, the monomer chosen for study is thiophene. 5
[0024] In another embodiment of the invention, the filler material taken is graphene and substrate used for deposition of Polythiophene-Graphene Layer is Carbon fiber.
[0025] In another embodiment of the invention, the medium of polymerization choose is aqueous (Deionized Water used as solvent). 10
[0026] In yet another embodiment of the invention, the dopant and oxidant chosen for above study was Sodium Dodecyl sulphate (SDS) and Ammonium per Sulphate (APS).
[0027] In yet another embodiment of the invention, the temperature of the polymerization condition was kept between 0-5°C. 15
[0028] In still another embodiment of the invention, the filler to monomer ratio was kept 0.25:1.
[0029] In still another embodiment of the invention, dopant to monomer and oxidant to monomer ratio was kept 1:1.
[0030] In further embodiment of the invention, the medium for the study was 20 aqueous i.e. deionised water used as solvent.
[0031] In further embodiment of the invention, the polymerisation reaction time was kept between 6-8 hours.
[0032] In yet further embodiment of the invention, the obtained composite was dried in vacuum oven at 50°C. 25
10
[0033] In still further embodiment of the invention, the prepared samples antistatic properties tested by John Chubb Instrument (JCI 155 v5) charge decay test unit.
Table 1: Room temperature anti-static decay (s) time from JCI plots
S. No.
Sample
Antistatic Decay (s)
1/e 10%
1.
CF
0.218 0.5
2.
PTh-CF
0.187 0.4
3.
PTh-Graphene-CF
0.181 0.2
5
[0034] The following examples are given to illustrate the process of the present invention and should not be construed to limit the scope of the present invention. However, the best mode requirement is served through the examples.
Example 1
Synthesis of SDS doped PTh grafted on Carbon Fiber: 10
[0035] The PTh coated carbon fiber was prepared by in-situ chemical oxidative polymerization of PTh in the presence of APS. Initially, we have taken 0.1 M Thiophene monomer and 0.1 M SDS used as dopant was taken in a beaker and then homogenized at 12000 rpm for 2 hrs in ultrasonicator to form a stable emulsion. After homogenization, the carbon fiber used as substrate cut with the 15 dimension of 50mm×70mm on which coating will perform is put into the emulsion of above prepared mixture and allowed to soak with the emulsion. After those 0.1 M APS taken into the burette and was added drop wise to the solution with continuous shaking on a rotary shaker by providing 0-5 ̊C temperature to the reaction by placing large ice cubes around the rotary shaker for 24 hrs. 20
11
Ultrasonication is done on the whole solution for 6 hrs. After 6 hrs, PTh decorated carbon fiber was obtained which is then washed with de-ionized water and then dried in vacuum oven for 24 hrs at 50 ºC.
Example 2
Synthesis of SDS doped PTh grafted with Graphene decorated on Carbon 5 Fiber:
[0036] The synthesis comprising following steps:
[0037] Step 1: 0.1 M Sodium dodecyl Sulphate (SDS) dopant solution was mixed with 0.1M Thiophene solution to make a homogeneous blend. The blend was homogenized at 10000 - 15000 rpm for 2 hrs to form a stable and uniform 10 emulsion solution.
[0038] Step 2: Then the 3D carbon fiber felt with dimensions 50 mm × 70 mm was put into the above prepared emulsion solution.
[0039] Step 3: Then, 0.1 g graphene is added into the above prepared mixture with carbon fiber. 15
[0040] Step 4: Then, 0.1 M APS solution act as oxidant for polymerisation reaction is taken in a burette and added drop wise to the above prepared solution with continuously shaking on a rotary shaker by providing 0-5 ºC temperature to the reaction by placing large ice cubes.
[0041] Step 5: Then after continuous shaking up to 6 hrs prepared sample was 20 filtered, washed and dried in oven at 50°C and final product named as PTh-Graphene-CF.

Claims:We Claim:
1. A polymer-graphene grafted carbon fiber composite as an antistatic protection shield material, said composite comprising thiophene monomer, graphene as filler material, and carbon fiber as substrate.
2. The composite as claimed in claim 1, wherein thiophene (Th) monomer is polymerized to yield polythiophene (PTh).
3. A process for preparing polymer-graphene grafted carbon fiber composite as an antistatic protection shield material, said process comprising the steps of:
a) using blank carbon fibre as antistatic shield material;
b) synthesising SDS doped PTh grafted on carbon fibre by in situ chemical oxidative polymerization of PTh in the presence of APS (ammonium per sulphate) as an oxidant;
c) synthesising SDS doped PTh grafted with graphene decorated on carbon fiber; and
d) Further evaluation of performance of said SDS doped PTh grafted with graphene decorated carbon fiber .
4. The process as claimed in claim 3 wherein synthesising SDS doped PTh grafted on carbon fibre by in situ chemical oxidative polymerization of PTh is performed by taking 0.1 M Thiophene monomer with 0.1 M SDS used as dopant in a beaker and then homogenizing at 12000 rpm for 2 hrs in ultrasonicator to form a stable emulsion.
5. The process as claimed in claim 4 wherein after homogenization, the carbon fiber used as substrate cut in the dimension of 50 mm × 70 mm on which coating is performed by putting into the emulsion and allowed to soak with the emulsion.
6. The process as claimed in claim 4, wherein 0.1 M APS is added drop wise to the solution with continuous shaking on a rotary shaker at 0-5 °C for 24 hrs followed by ultrasonication for 6 hrs in order to obtain PTh decorated carbon fiber which is then washed with de-ionized water and then dried in vacuum oven for 24 hrs at 50 ºC.
7. The process as claimed in claim 3, wherein synthesising SDS doped PTh grafted with graphene decorated on carbon fiber is performed by adding 0.1 g graphene into PTh decorated carbon fiber.
8. The process as claimed in claim 7, wherein 0.1 M APS solution is further added drop wise with continuous shaking on a rotary shaker at 0-5 ºC as an oxidant for polymerisation reaction.
9. The process as claimed in claim 8, wherein the final product PTh-Graphene-CF is obtained after continuous shaking up to 6 hrs, filtered, washed and dried in oven at 50 °C.
10. The process as claimed in claim 3, wherein further evaluation of performance of PTh-graphene deposited carbon fiber composite shows the least anti-static decay time of 0.2 (s) while PTh-deposited carbon fibre composite shows 0.4 (s) for 10 % criterion.
, Description:FIELD OF THE INVENTION
[001] The present invention relates to development of Conducting Polymer based composite as antistatic shield material for forming packages or for electrostatically sensitive components principally for protecting them from potential damages from electrostatic charges.
BACKGROUND AND PRIOR ARTS OF THE INVENTION
[002] Conducting polymers with an extended conjugated system, such as Polythiophene, Polypyrrole or Polyaniline, are known to be widely utilized due to their interesting electrical, optical and chemical characteristics, good thermal and environmental stability, low toxicity, easy polymerization, adjustable electrical conductivity, etc. In addition they can be made from readily available and inexpensive starting materials. The current invention relates the fabrication of Polythiophene-Graphene grafted Carbon fiber composite as an efficient antistatic shield material for electronic components. The damage from electrostatic discharge has become major concern in electronic components and units. Furthermore, Antistatic safety is also required for elements where relative motion between varied materials occurs like weaving machine hands, plane tyres and so on. Martin et al. (2004) have reported that PEDOT/PSS (poly (3,4-ethylenedioxythiophene) polystyrene sulfonate) composite plays an important commercial role in anti-static coatings or conductive coatings in electronic components. Polythiophene based antistatic shield materials can be prepared either by chemical synthesis or it may be electrochemically deposited on the substrate surface. Furthermore, Kusy et al. (1986) observed that antistatic protection is also required for parts where relative motion between dissimilar materials occurs like weaving machine arms, airplane tyres, etc. Conventional polymers commonly being used for packaging of various electronic equipments but due to their inherent electrical insulating nature, these polymers failed to dissipate the static or electrostatic charge. For this the use of conducting blends and composites with traditional polymers as an electrostatic charge dissipative fabric is one of the promising application of conducting polymers which combines the mechanical properties of conventional polymers and electrical properties of conducting polymers.
[003] Following are the works done so far in the field of Conducting Polymers based antistatic shield Materials:
[004] WO 2013127500 relates to the fabrication of a layered structure which can be employed in the field of polarization filters, in particular for shielding polarization filters from electrostatic discharge and electromagnetic radiation. The shielding can serve on the one hand to increase the stability of polarization filters and on the other hand to improve the quality of the filters. The patent furthermore relates to a process for the production of a layered structure which can be employed as shielding for polarization filters, and a device having a layered construction according to the patent. The layered structure according to invention comprises cellulose ester as polarizer layer and at least one conductor layer comprising a conductive polymer. The conductive polymer is chosen from the group consisting of a thiophene, a polyacetylene, a polyparaphenylene, a polyaniline and a polypyrrole or a mixture of at least two of these.
[005] US 20100190924 relates to electrically conductive and non-conductive polymer composite materials suitable for use in electrically conductive materials, electromagnetic wave shielding materials, heating elements, antistatic materials, is substitutes for existing polymer composites, and the like. This application also relates to methods of making the electrically conductive and non-conductive polymer composite materials. The conducting polymer composite is the blend of conducting polymer and conducting filler wherein the conducting filler is electro-conductive fillers selected from the group consisting of graphite, carbon black, carbon fiber, carbon nanofiber, carbon nanotubes, intrinsically conducting materials, and mixtures thereof. The patent provides rapid, facile and low-cost methods for making conductive and non-conductive polymer composites, wherein the polymer composites are manufactured by in situ polymerization at room temperature. Within a short period time (preferentially for example, less than 10 minutes) after being administered, the composition forms a network that develops with high strength and functional (for example, electrically conductive) composites. The resulting composites can be molded into any shape and/or size and exhibits excellent mechanical properties. According to one aspect, the invention provides methods for making polymer composites from cyanoacrylate monomers and starches as filler by in situ polymerization. In another aspect, the invention provides methods for making conducting polymer composites from using the polymerized cyanoacrylate-starch polymer composites as a matrix.
[006] US 20150284141 relates to multi-layered materials as anti-static shield comprising an electrically conductive layer and a support layer. This invention relates to anti-static materials which protect devices which are sensitive to electrostatic discharge and/or shock. The electrically conductive layer consists of an electrically conductive polymer or an electrically conductive polymer composite. The conjugated conductive polymer used for making electrically conductive layer comprises poly(phenylenevinylenes), polyfluorenes, poly(spirobifluorenes), polythiophenes, poly(p-phenylenes), poly(anilines), poly(pyrroles), copolymers thereof, or mixtures thereof.
[007] EP 0554588 relates to a sheet or web material having antistatic properties. A sheet material is developed that comprising of a hydrophobic resin support or paper support coated with at least one hydrophobic resin layer wherein said resin support or resin layer is coated with a transparent antistatic layer containing as an essential component an oxidatively polymerized polythiophene with conjugated polymer backbone in the presence of a polymeric polyanion compound. The antistatic layer is coated with an overlying adhering barrier layer applied from aqueous polymer dispersion, i. e. polymer latex, wherein said polymer has hydrophilic functionality sufficient to render said overlying layer adherent to a thereon coated hydrophilic colloid-containing layer.

OBJECTS OF THE INVENTION:
[008] The primary objective of the present invention is development of Conducting Polymer-Graphene grafted carbon fiber as antistatic shield material for electronic components, chip carriers, electrostatically sensitive components and protecting them from potentially damages from electrostatic charges.
[009] Another objective of the invention to design conducting polymer composite incorporating filler materials and by selecting a medium of synthesis of prepared composite.
SUMMARY OF THE INVENTION
[0010] The present invention provides a process of synthesizing conducting polymers with a filler material coated over a carbon fiber substrate in aqueous medium. The method comprising synthesizing Polythiophene with graphene as filler deposited over carbon fiber substrate, SDS and APS used as dopant and oxidant during the oxidative polymerization of thiophene monomer, testing the antistatic properties by John Chubb Instrument (JCI 155 v5) charge decay test unit, and antistatic performance of prepared composite (50 x 70 mm2 Dimensions) by measuring the time on applying the positive as well as negative high corona voltage of 5000 V on the surface of material to be tested and recorded the decay time at 10 % cutoff. Investigation is performed for the anti-static behaviour of blank carbon fibre, polythiophene and polythiophene-graphene grafted carbon fiber composites. The polythiophene and polythiophene-graphene grafted carbon fiber composites showed static decay time in the order of 0.2–0.5 sec at 10% cut-off. Based on the obtained results, it may be concluded that polythiophene and polythiophene-graphene grafted over carbon substrate can be utilized as effective shield materials for static charge.
[0011] The product part constitutes a polymer-graphene grafted carbon fiber composite as an antistatic protection shield material, said composite comprising thiophene monomer, grapheme as filler material, and carbon fiber as substrate wherein thiophene (Th) monomer is polymerized to yield polythiophene (PTh).
[0012] The process part for preparing polymer-graphene grafted carbon fiber composite as an antistatic protection shield material, said process comprising the steps of using blank carbon fibre as antistatic shield material; synthesising SDS doped PTh grafted on carbon fibre by in situ chemical oxidative polymerization of PTh in the presence of APS (ammonium per sulphate) as an oxidant; synthesising SDS doped PTh grafted with graphene decorated on carbon fiber; and further evaluation of performance of said SDS doped PTh grafted with graphene decorated carbon fiber. Further evaluation of performance of PTh-graphene deposited carbon fiber composite shows the least anti-static decay time of 0.2 (s) while PTh-deposited carbon fibre composite shows 0.4 (s) for 10 % criterion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In the drawings accompanying this specification:-
[0014] Fig. 1: Schematic of the synthesis of Polythiophene-Graphene grafted carbon fiber composite by chemical oxidative polymerization process.
[0015] Fig. 2: XRD pattern of (a) Carbon fiber (b) PTh-CF composite and (c) PTh-CF-Graphene Composite
[0016] Fig. 3: FE-SEM images of (a) bare carbon fiber (b) PTh grafted on carbon fiber (c) PTh-Graphene composite grafted on carbon fiber
[0017] Fig. 4: Antistatic results of (a) Carbon Fiber (b) CF-PTh (c) CF-PTh-Graphene composite
DETAILED DESCRIPTION OF THE INVENTION
[0018] At the very outset of the detailed description, it may be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only exemplary embodiment, and without intending to imply any limitation on the scope of this invention. Accordingly, the description is to be understood as an exemplary embodiment and teaching of invention and not intended to be taken restrictively.
Materials and Reagents Used:
[0019] Thiophene (99% Sigma-Aldrich) was purified by distillation at reduced pressure and stored in a refrigerator before use. Sodium dodecyl sulfonate (SDS) (Merck chemicals, India) used as a dopant, Ammonium per sulphate (APS) (Merck chemicals, India) used as oxidant and hydroxyl peroxide (H2O2, 30% solution) (Merck chemicals, India) used as a co-oxidant. Acetone, methanol, and chloroform are all analytical grade reagents purchased from Rankem Limited, India, and were used as received. Graphene (XG Sciences, United States) was used as such without any purification. Double deionized water (specific resistivity of 106 O cm) was used to prepare aqueous solutions. Carbon fibre felt (3DTorayca T-300 carbon fibres 3D structure) purchased from Toray, USA.

[0020] The present invention describes a process for synthesizing Polythiophene with Graphene by using SDS as dopant, APS as oxidant and carbon fiber as substrate in an aqueous medium. The method comprises synthesizing Polythiophene with graphene as filler deposited over carbon fiber substrate wherein SDS and APS used as dopant and oxidant during the oxidative polymerization of thiophene monomer, then testing the antistatic properties by John Chubb Instrument (JCI 155 v5) charge decay test unit. Antistatic performance of prepared composite (50 x 70 mm2 dimensions) by measuring the time on applying the positive as well as negative high corona voltage of 5000 V on the surface of material to be tested and recorded the decay time at 10 % cutoff. The polymer chosen for deposition over carbon fiber substrate is Polythiophene and the like. The medium of polymerisation was aqueous i.e. deionised water used as solvent and the like. The dopant and oxidant chosen was Sodium dodecyl sulphate (SDS) and ammonium per sulphate (APS) during the polymerization of monomer thiophene and the like. The monomer thiophene encapsulated with graphene and deposited over carbon fiber substrate. The prepared samples tested by John Chubb Instrument (JCI 155 v5) charge decay test unit. The antistatic performance of prepared composite (50 x 70 mm2 Dimensions) evaluated by measuring the decay time on applying the positive as well as negative high corona voltage of 5000 V on the surface of material to be tested and recorded the decay time at 10 % cutoff.
[0021] The PTh coated carbon fiber was prepared by in-situ chemical oxidative polymerization of PTh in the presence of APS. Initially, we have taken 0.05 – 0.2 M Thiophene monomer and 0.05 – 0.2 M SDS used as dopant was taken in a beaker and then homogenized at 10,000 – 15,000 rpm for 2 hrs in ultrasonicator to form a stable emulsion. After homogenization, the carbon fiber used as substrate cut with the dimension of 50 mm × 70 mm on which coating will perform is put into the emulsion of above prepared mixture and allowed to soak with the emulsion. After those 0.05 – 0.2 M APS taken into the burette and was added drop wise to the solution with continuous shaking on a rotary shaker by providing 0-5 ° C temperature to the reaction by placing large ice cubes around the rotary shaker for 12-48 hrs. Ultrasonication is done on the whole solution for 4-8 hrs. After that, PTh decorated carbon fiber was obtained which is then washed with de-ionized water and then dried in vacuum oven for 12-48 hrs at 30-70 ºC.
[0022] For the preparation of Polythiophene grafted graphene deposited over carbon fiber felt substrate, the protocol used at the first Step is to take 0.05 – 0.2 M Thiophene monomer and 0.05 – 0.2 M Sodium dodecyl Sulphate (SDS) solution was taken in beaker and then homogenized at 10000 - 15000 rpm for 1-3 hrs to form a stable emulsion. In second step, the carbon fiber with dimensions 50 mm × 70 mm is put into the emulsion solution. In third step, 0.05 – 0.2 gm graphene is added into the above prepared mixture with carbon fiber. Then, 0.05 – 0.2 M APS solution act as oxidant for polymerisation reaction is taken in a burette and added drop wise to the above prepared solution with continuously shaking on a rotary shaker by providing 0-5 ºC temperature to the reaction by placing large ice cubes. Then after continuous shaking up to 6hrs prepared sample was filtered, washed and dried in oven at 30-70 °C.
Embodiments
[0023] In one embodiment of the invention, the monomer chosen for study is thiophene.
[0024] In another embodiment of the invention, the filler material taken is graphene and substrate used for deposition of Polythiophene-Graphene Layer is Carbon fiber.
[0025] In another embodiment of the invention, the medium of polymerization choose is aqueous (Deionized Water used as solvent).
[0026] In yet another embodiment of the invention, the dopant and oxidant chosen for above study was Sodium Dodecyl sulphate (SDS) and Ammonium per Sulphate (APS).
[0027] In yet another embodiment of the invention, the temperature of the polymerization condition was kept between 0-5°C.
[0028] In still another embodiment of the invention, the filler to monomer ratio was kept 0.25:1.
[0029] In still another embodiment of the invention, dopant to monomer and oxidant to monomer ratio was kept 1:1.
[0030] In further embodiment of the invention, the medium for the study was aqueous i.e. deionised water used as solvent.
[0031] In further embodiment of the invention, the polymerisation reaction time was kept between 6-8 hours.
[0032] In yet further embodiment of the invention, the obtained composite was dried in vacuum oven at 50°C.
[0033] In still further embodiment of the invention, the prepared samples antistatic properties tested by John Chubb Instrument (JCI 155 v5) charge decay test unit.
Table 1: Room temperature anti-static decay (s) time from JCI plots
S. No. Sample Antistatic Decay (s)
1/e 10%
1. CF 0.218 0.5
2. PTh-CF 0.187 0.4
3. PTh-Graphene-CF 0.181 0.2

[0034] The following examples are given to illustrate the process of the present invention and should not be construed to limit the scope of the present invention. However, the best mode requirement is served through the examples.
Example 1
Synthesis of SDS doped PTh grafted on Carbon Fiber:
[0035] The PTh coated carbon fiber was prepared by in-situ chemical oxidative polymerization of PTh in the presence of APS. Initially, we have taken 0.1 M Thiophene monomer and 0.1 M SDS used as dopant was taken in a beaker and then homogenized at 12000 rpm for 2 hrs in ultrasonicator to form a stable emulsion. After homogenization, the carbon fiber used as substrate cut with the dimension of 50mm×70mm on which coating will perform is put into the emulsion of above prepared mixture and allowed to soak with the emulsion. After those 0.1 M APS taken into the burette and was added drop wise to the solution with continuous shaking on a rotary shaker by providing 0-5 °C temperature to the reaction by placing large ice cubes around the rotary shaker for 24 hrs. Ultrasonication is done on the whole solution for 6 hrs. After 6 hrs, PTh decorated carbon fiber was obtained which is then washed with de-ionized water and then dried in vacuum oven for 24 hrs at 50 ºC.
Example 2
Synthesis of SDS doped PTh grafted with Graphene decorated on Carbon Fiber:
[0036] The synthesis comprising following steps:
[0037] Step 1: 0.1 M Sodium dodecyl Sulphate (SDS) dopant solution was mixed with 0.1M Thiophene solution to make a homogeneous blend. The blend was homogenized at 10000 - 15000 rpm for 2 hrs to form a stable and uniform emulsion solution.
[0038] Step 2: Then the 3D carbon fiber felt with dimensions 50 mm × 70 mm was put into the above prepared emulsion solution.
[0039] Step 3: Then, 0.1 g graphene is added into the above prepared mixture with carbon fiber.
[0040] Step 4: Then, 0.1 M APS solution act as oxidant for polymerisation reaction is taken in a burette and added drop wise to the above prepared solution with continuously shaking on a rotary shaker by providing 0-5 ºC temperature to the reaction by placing large ice cubes.
[0041] Step 5: Then after continuous shaking up to 6 hrs prepared sample was filtered, washed and dried in oven at 50°C and final product named as PTh-Graphene-CF.