Thank you Dio! I'm always afraid to take a closer look and lose myself.
That's a massive rabbit hole! If you look at citations alone. One document is another Talga patent and at a quick glance it describes the process for graphene production in detail.
View attachment 58004
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A suitable graphite material "Vittangi graphite", being a strong, conductive graphite bearing ore, was identified and is available to the Applicant in the Nunasvaara deposit in Sweden, being a predominantly microcrystalline flake Joint Ore Reserves Committee (JORC 2012) mineral resource of 9.8 Mt at 25.3% - 46.7% graphite (Cg). Grades for this deposit have been drill tested at an average of 35% Cg, with grades attaining up to 46.7% Cg. The rock strength has been measured at approximately 120 MPa and the resistivity at less than 10 Ohm-meter, for example 0.0567 Ohm-meter. A graphite deposit of the nature of the Nunasvaara deposit in Sweden would not be, and has not been to date, considered an appropriate source of graphitic material feedstock for the production of graphene. Graphite bearing ore obtained from the Nybrannan deposit as part of the Jalkunen Project is also a suitable material that is available to the Applicant for the production of graphene.
The graphite ore is extracted by known quarry mining methods with abrasive disks, saws or wires and other known non-explosive methods of rock extraction in an ore extraction step. The blocks of ore obtained have sizes which are suitable for transport, transfer movement, and handing. The blocks may be further cut into smaller shapes or forms of electrodes which are considered more suitable for presentation to an electrolytic process. The blocks may be cubic, cylindrical, trapezoidal, conical, or rectangular in shape and have a preferred minimum dimension of 50 mm and maximum dimension of 2000 mm. More particularly, the blocks have a minimum dimension of 100 mm and maximum dimension of 1000 mm, or still more particularly a minimum dimension of 150 mm and maximum dimension of 500 mm.
The ore blocks from the graphitic deposit are employed directly as electrodes in electrolysis for the production of nano-micro platelet graphite. In this embodiment the extracted graphite ore is used as the anode, copper metal is used as the cathode and the electrolytic treatment is carried out in the presence of a 1M ammonium sulphate solution having a pH of 6.5-7.5. The voltage applied to exfoliate the extracted graphite into nano-micro platelet graphite was 10V and the ammonium sulphate solution was concurrently stirred at lOOOrpm.
The nano-micro platelet graphite obtained after the electrolytic treatment has substantially unaltered properties relative to the graphite ore from which it is produced. Moreover, the obtained nano-micro platelet graphite exhibited increased interlayer spacing between adjacent graphitic sheets relative to the observed interlayer spacing of nano-micro platelet graphite obtained from synthetic graphite or highly ordered pyrolytic graphite (HOPG).
Following the electrolytic treatment and before further exfoliation of the micro- nano platelet graphite into graphene, sulphate anions were separated from the solution containing the micro-nano platelet graphite. This was achieved by subjecting the solution containing the micro-nano platelet graphite to a liquid-liquid separation treatment in which the solution was added to kerosene. Since sulphate anions are more soluble in kerosene than in water they readily migrate and are solubilised into the organic solvent, which facilitates their removal from the solution containing the micro- nano platelet graphite. The micro-nano platelet graphite obtained following this beneficiation treatment comprises 80-99% by weight of carbon.
The micro-nano platelet graphite obtained from the beneficiation treatment was then subjected to a combined chemical and high pressure exfoliation treatment. The chemical treatment involves mixing the micro-nano platelet graphite (100 g) with an aqueous ammonium tetrabutyl ammonium sulphate solution (0.5 wt %) to intercalate ammonium ions between the graphitic layers of the micro-nano platelet graphite. It will be appreciated that an ammonium persulphate solution (0.5 wt %) could be used instead of the ammonium sulphate solution. The aqueous ammonium sulphate solution additionally comprises Antiterra 250 (1 wt %) and/or DISPERBYK 2012 (2 wt %) both of which are manufactured by BYK. This solution is then kept at room temperature and pressure for a period of 7 days to increase the content of intercalated ammonium ions between the graphitic layers.
The solution containing the intercalated micro-nano platelet graphite and surfactants is then subjected to a high pressure treatment in an M-l 10Y high pressure pneumatic homogenizer which involves the use of a high pressure jet channel in an interaction mixing chamber. The solution containing intercalated micro-nano platelet graphite and surfactants is pumped from opposite sides of the homogeniser into the mixing chamber. This causes two highly accelerated liquid dispersion streams to collide with pressurised gas (1200 bar), resulting in de-agglomeration of the graphitic layers and the exfoliation of single-layer and few-layer graphene in high yield. The combination of high pressure and reduced bond strength between adjacent graphitic layers of the micro-nano platelet graphite increases the amount of single-layer graphene and few-layer graphene that is formed relative to graphene that is exfoliated from graphite using a high sheer exfoliation route. Advantageously, it has been found that by following the method of the present invention the graphene yield could be increased by 20-40% relative to the graphene yields obtained when using conventional high shear treatments to exfoliate graphene from graphite.
Following the combined chemical and high pressure exfoliation treatment the solution obtained is ultra-centrifuged at 10,000-12,000 rpm for 30 minutes using a Fisher scientific Lynx 4000 or Beckmann Coulter (ProteomeLab® XL- A) centrifuge in order to substantially separate the exfoliated graphene from any residual nano-micro platelet graphite.
Example 2: Epoxy coated substrate preparation
A functionalised graphene composition was first prepared by dispersing graphene (1 wt%) in xylene (3.75 wt%) using a dispersing agent (0.25 wt%). In this embodiment the dispersing agent was BYK9076. This solution, which contains "pre- functionalised" graphene, i.e. graphene that has been functionalised with the BYK9076 dispersing agent, was then mixed with a polyamide hardener (23.75 wt%) and this solution was stirred for 5 minutes at 2000 RPM using a paint mixer to ensure that the graphene is homogeneously dispersed throughout the hardener and that graphene is further functionalised with the hardener to obtain functionalised graphene, i.e. graphene that is functionalised with the dispersing agent and with the hardener. 71.25 wt% of bisphenol A diglycidyl ether (DGEBA) resin was then added to the composition comprising functionalised graphene and this mixture was stirred for 5 minutes at 2000 RPM. The functionalised graphene and epoxy resin mixture was then coated onto a mild steel substrate and the steel substrate was thereafter subjected to a heat treatment of 150°C for 15 mins to cure the resin and to form a hardened coating having a dry film thickness of 45 microns.
Example 3 : Corrosion performance
Immersion test: An immersion test was carried out in accordance with ASTM D6943 to assess the corrosion resistance of a DGEBA epoxy coating without graphene and DGEBA epoxy coatings with different loadings (0.1%, 0.5%, 1%, 5%) of functionalised graphene. The coatings were scratched and then the coated substrates were immersed in a 3.5% NaCl solution. The results showed that the DGEBA epoxy coating exhibited severe corrosion and that the extent of corrosion decreases with increasing graphene content. The samples that contained 1 % and 5% functionalised graphene exhibited the least corrosion damage.
Electrochemical analysis: Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic Polarization (LP) tests were carried out to obtain a quantitative understanding of how the content of functionalised graphene in DGEBA epoxy coatings influences corrosion resistance and the rate of corrosion.
As shown in Figure 2, DGEBA epoxy coated samples without functionalised graphene (0%) provide the least coating impedance and hence resistance against corrosion. Figure 2 also shows that an increasing functionalised graphene content increases the impendence value and hence the coating resistance. In particular, it can be seen that the impedance value reached nine orders of magnitude when 1 % of functionalised graphene was incorporated into the DGEBA epoxy coating and that a significant increase in impendence was observed when the functionalised graphene content was increased from 0.5 % to 1 %.
Figure 3A shows the results of a set of potentiodynamic polarization experiments that were carried out to evaluate the effect of functionalised graphene content (0.1 wt% (A), 0.5 wt% (B), 1 wt% (C), and 5 (D) wt%) on the rate of corrosion. These experiments were carried out at 250 mV above and below the open circuit potential. From Figure 3A it can be seen that increasing the content of functionalised graphene in the DGEB A epoxy coating results in a significant reduction in the corrosion rate relative to the observed corrosion rate for DGEBA epoxy coatings without functionalised graphene (E).
Table 1 shows the results of a set of potentiodynamic polarization experiments that compared the rates of corrosion of an epoxy coating comprising 1 wt% of well dispersed functionalised graphene with an epoxy coating comprising non- functionalised graphene. This is also represented graphically in Figure 3B.
Table 1
The results showed that significant improvements in corrosion resistance could be obtained when the epoxy coating comprised well dispersed functionalised graphene rather than graphene that was merely added to the epoxy resin, i.e. it was not functionalised with the dispersing agent and the hardener prior to combining with the epoxy resin. Example 4: Adhesion test
A pull off adhesion test was carried out in accordance with ASTM G 4541. Experiments were carried out to investigate the adhesion strength of DGEBA epoxy coatings without graphene and DGEBA epoxy coatings that comprise 1 wt% graphene. As shown in Table 2 below, the pull off strength of the DGEBA epoxy coating is 2.6 MPa, whereas the pull off strength of the DGEBA epoxy coating with 1 wt % functionalised graphene is significantly higher at 4.8 MPa. The increased adhesion has been attributed, at least in part, to both the dispersing agent and the hardener forming a cross-linked network with the epoxy resin, whereas in the conventional DGBEA epoxy coating a cross-linked network is only formed between the hardener and the epoxy resin.
Table 2
Example 5: Tensile and elongation tests
Experiments were also carried out in accordance with ASTM D 882 to evaluate the tensile properties of DGBEA epoxy coatings and DGEBA epoxy coatings comprising 1 wt % functionalized graphene. Test samples were prepared by applying the coatings onto parchment paper using a bar applicator (75 microns wet film thickness). On curing, the coatings were peeled off and test samples were cut to the desired shape and size. The thickness and gauge length of the test samples were measured and thereafter they were mounted within the Universal Testing Machine. Table 3 below shows the tensile properties of DGBEA epoxy coatings and DGEBA epoxy coatings comprising 1 wt % functionalized graphene. In particular, Table 2 shows that significant improvements in tensile strength can be obtained by incorporating at least 1 wt% of functionalised graphene into the DGEBA epoxy coating. Moreover, it can be seen that the DGEBA epoxy coating comprising functionalised graphene exhibits a two-fold improvement in elongation relative to the DGEBA epoxy coating without graphene.
Table 3
Example 6: Abrasion strength test
Abrasive strength was measured using a Taber Abrasion method (ASTM D4060). A square steel substrate was first coated with (i) the functionalised graphene based DGEBA epoxy coating and (ii) the DGEBA epoxy coating without functionalised graphene. Then a hole measuring 1cm in diameter was drilled in the centre of the coated substrate. The weight of the coated substrate was measured and then the coated substrate was fixed to the Taber Abrasion tester with the help of a screw. Based on the hardness of the coating, different abrasive wheels can be used. CS17 wheels are generally used to test epoxy based systems. The coated substrate rotates for 1000 cycles, rubbing against the wheels, after which the weight of the substrate is measured again. The difference in the weight provides an estimate of the coating material loss and hence the abrasive strength of the coating. As shown in Table 4, the incorporation of functionalised graphene into the DGEBA epoxy coating significantly improves the abrasive strength of the coating relative to the DGEBA epoxy where functionalised graphene is absent from the coating matrix.
Table 4
Example 7: Weathering test
Experiments were carried out to evaluate the weathering properties of DGBEA epoxy coatings and DGEBA epoxy coatings comprising 1 wt % functionalized graphene. Experiments were conducted in accordance with ASTM G-154 using a QUV weatherometer. The coatings were subjected to a cyclic test with each cycle consisting of 8h of exposure to "UV light" at 60°C and thereafter condensation for 4h at 50°C. A spectrophotometer (BYK) was used to assess any changes in the colour and gloss of the coatings. Figure 4A shows the variation in colour change (ΔΕ) vs exposure, whereas Figure 4B shows the variation in gloss change (AG). The results indicate that the epoxy functional group in the epoxy coating (without functionalised graphene) deteriorates on exposure to UV light. Moreover, it can be seen that there is a sudden reduction in ΔΕ and AG within the first 200 hours of exposure to UV light. Although a decrease in ΔΕ and AG is also observed within the first 200 hours for epoxy coatings comprising functionalised graphene, the reduction is less severe. This improvement in colour change and gloss properties has been attributed to the presence of functionalised graphene in the coating matrix that is able to absorb UV radiation. Example 8: Water absorption test
The water absorption properties of the functionalised graphene epoxy coating, were compared with an organic zinc rich DGEBA epoxy primer and an inorganic zinc silicate primer. Figure 8 shows that overtime the functionalised graphene epoxy coating absorbs the least amount of water and that it absorbs much less than the zinc rich epoxy primer. Water uptake was calculated by measuring the changes in coating's electrical capacitance over long exposure to aqueous environments using electrochemical impedance spectroscopy (EIS). Capacitive technique is based on the principle that water permeation increases the electrical capacitance of coating. Example 9: Polyurethane coated substrate preparation
A functionalised graphene composition was first prepared by dispersing graphene (5 wt%) in water (4.5 wt%) using a dispersing agent (0.5 wt%). In this embodiment the dispersing agent was DISPERBYK2012. This solution, which contains "pre-functionalised" graphene, i.e. graphene that has been functionalised with the DISPERBYK2012 dispersing agent, was then mixed with a water based DMPA polyol dispersion (60 wt%) and this solution was stirred for 5 minutes at 2000 RPM using a paint mixer to ensure that the graphene is homogeneously dispersed throughout the polyol resin and that graphene cross-links with the polyol resin to obtain functionalised graphene, i.e. graphene that is functionalised with the dispersing agent and with the polyol. 30 wt% of 6-hexamethylene diisocyanate (HDI) hardener was then added to the composition comprising functionalised graphene and this mixture was stirred for 10 minutes at 2000 RPM. The functionalised graphene and HDI hardener mixture was then coated onto a mild steel substrate and the steel substrate was thereafter subjected to a heat treatment of 100°C for 15 mins to cure the DMPA resin and to form a hardened coating having a dry film thickness of 40 microns.
Example 10: Adhesion test
A pull off adhesion test was carried out in accordance with ASTM G 4541. Experiments were carried out to investigate the adhesion strength of polyurethane coatings without functionalised graphene and polyurethane coatings that comprising 5 wt% graphene. As shown in Table 5, the pull off strength of the polyurethane coating without functionalised graphene is 3.8 MPa, whereas the pull off strength of the functionalised graphene polyurethane coating is much higher at 5.4 MPa %.
Table 5
Example 11: Tensile and elongation tests
Experiments were also carried out in accordance with ASTM D 882 to evaluate the tensile properties of DMPA polyurethane coatings comprising 5 wt % functionalized graphene. Test samples were prepared by applying the coatings onto parchment paper using a bar applicator (75 microns wet film thickness). On curing, the coatings were peeled off and test samples were cut to the desired shape and size. The thickness and gauge length of the test samples were measured and thereafter they were mounted within the Universal Testing Machine. Table 6 below shows that significant improvements in tensile strength and elongation were obtained when 5 wt% of functionalised graphene is incorporated into the polyurethane coating. Table 6
Example 12: Abrasion strength test
Abrasive strength was measured using a Taber Abrasion method (ASTM D4060). A square steel substrate was coated with (i) the functionalised graphene based DMPA polyurethane coating and (ii) the DMPA polyurethane coating without functionalised graphene, and a hole measuring 1cm in diameter was drilled in the centre of the coated substrate. The weight of the coated substrate was measured and then the coated substrate was fixed to the Taber Abrasion tester with the help of a screw. The coated substrate was rotated for 1000 cycles against a CS17 abrasive wheel after which the weight of the substrate is measured again. As shown in Table 7, the incorporation of 5 wt% functionalised graphene into the DMPA polyurethane coating significantly improves the abrasive strength of the coating relative to the DMPA polyurethane coating where functionalised graphene is absent from the coating matrix.
Table 7
Example 13: Weathering test
Experiments were carried out to evaluate the weathering properties of polyurethane coatings formed in accordance with Example 9 comprising 5 wt% functionalised grapheme and polyurethane coatings without functionalised graphene. Experiments were conducted in accordance with ASTM G-154 using a QUV weatherometer. The coatings were subjected to a cyclic test with each cycle consisting of 8h of exposure to "UV light" at 60°C and thereafter condensation for 4h at 50°C. A spectrophotometer (BYK) was used to assess any changes in the colour and gloss of the coatings. Figure 5A shows the variation in colour change (ΔΕ) vs exposure, whereas Figure 5B shows the variation in gloss change (AG). The results indicate that at any given time the ΔΕ values observed for the polyurethane coatings comprising functionalised graphene were significantly lower than the ΔΕ values that were obtained for the corresponding polyurethane coating without functionalised graphene. Similarly, the AG values observed for the functionalised graphene polyurethane coating were less than those observed for the polyurethane coating without graphene.
The above embodiments are described by way of
example only. Many variations are possible without departing from the scope of the invention."
Functionalised Graphene Composition The present invention relates to a graphene composition for use in a coating composition that comprises a resin and a hardener, wherein the resin or the hardener is an active hydrogen-containing component and graphene in the graphene composition is...
patents.google.com
It gets even better:
View attachment 58005
That's a whole family of patents!! Holy shit. Semmel, you're sure to find plenty of numbers.
And pay attention to the release dates!