Process for preparing stable and homogeneous dispersions of sp2 carbon allotropes in lipophilic matrixes and related composite materials obtainable therefrom

Abstract

A process is described for preparing lipophilic matrix composites comprising dispersions of sp2 carbon allotropes comprising the steps of (A) mixing the sp2 carbon allotrope with a compound containing a pyrrole ring of formula (i) wherein: - R1 and R3 are, independently of each other, hydrogen or an alkyl group containing a number of carbon atoms ranging from 1 to 20; - R3 is a linear or branched aliphatic group, with or without unsaturation, unsubstituted and not containing functional groups such as for example OH, C=O, said R3 containing a number of carbon atoms ranging from 1 to 40; (B) heating the mixture; (C) mixing the mixture obtained in step (B) with a compound of a lipophilic nature that forms the matrix of a composite material obtaining a composite.

Description

[0001] PROCESS FOR PREPARING STABLE AND HOMOGENEOUS DISPERS IONS OF sp2CARBON ALLOTROPES IN LIPOPHILIC MATRIXES AND RELATED COMPOS ITE MATERIALS OBTAINABLE THEREFROM

[0002] DESCRIPTION

[0003] The present invention relates to a process for preparing homogeneous dispersions o f sp2carbon allotropes , in particular allotropes having at least one dimension smaller than 100 nm such as graphene and nanographite , which are stable in lipophilic matrixes due to the improved dispersion of said allotropes in said lipophilic matrixes .

[0004] In particular, the present invention relates to a process as defined above for facilitating the dispersion of sp2carbon allotropes and their compatibi lity in lipophilic matrixes such as elastomeric matrixes ( e . g . unsaturated elastomers such as natural rubber or saturated elastomers such as ethylene / propylene copolymers , which can be used to obtain gaskets , conveyor belts and the like ) and / or polymeric matrixes , including non-elastomeric ones , with the consequent improvement in dynamic-mechanical properties , such as a lower non-linearity of the elastic modulus ( G' when measured with shear stress ) and therefore a lower value of its variations (AG' ) as elongation varies , due to the reduction in the amount of the lattice formed by the allotrope itself; lubricating base oils resulting in better stability of allotrope dispersion in the lubricant; lubricating greases with improved lubricating power due to the homogeneous dispersion of the allotrope; waxy compounds such as paraffinic waxes, animal waxes, vegetable waxes or other waxy compounds (e.g. methyl esters of saturated fatty acids with a number of C atoms greater than or equal to C12 up to 32, e.g. derivatives of lauric acid, stearic acid) with improved stability of the carbon allotrope dispersion in the wax matrix, when the wax matrix is above its melting point. More particularly, the present invention relates to composite materials comprising functionalised sp2carbon allotropes, obtainable by the above process, which can be used as additives (e.g. masterbatch) for lubricating oils, lubricating greases, and / or elastomeric compositions.

[0005] In chemistry, allotropes are forms of chemical elements that differ in the way the atoms are bonded together.

[0006] Carbon is one of the chemical elements known in various allotropic forms and the classification of carbon allotropes is generally made on the basis of the hybridisation of the carbon atoms: carbon is sp3hybridised in diamond while carbon is sp2hybridised in carbon black, graphite, nano-graphite, graphene, fullerene, carbon nanotubes , almost all of which are generally used in the preparation of composite materials .

[0007] Graphites , carbon nanotubes and carbon black are made up of di f ferently organised layers of graphene , and a graphene layer is an aromatic polycondensate system consisting of a layer of carbon atoms with the thickness of a single carbon atom .

[0008] The aforementioned sp2carbon allotropes , hereafter also referred to as carbonaceous material , are polymeric in nature . Repetitive units are aromatic cycles , typically with 5 or 6 carbon atoms .

[0009] The sp2carbon allotropes are traditionally divided into "nano" and "nano-structured" .

[0010] A chemical is defined as "nano" when at least one dimension is less than 100 nm : graphene , nano-graphites , fullerene , and carbon nanotubes belong to this category .

[0011] Carbon black, on the other hand, which is used for reinforcing polymeric materials and for many other applications , is "nano-structured" in that it consists of fundamental spherical particles , which are nanometric in si ze , j oined to form aggregates in which these fundamental particles are held together by covalent bonds . These aggregates are larger than 100 nm . The thermomechanical stresses typical of the mixing action of carbon black with polymer matrixes and the thermomechanical stresses to which composite materials are subj ected during their application are unable to separate the aggregates into their fundamental components .

[0012] The sp2carbon allotropes have great electrical and thermal conductivity as a result of their aromatic nature and structure , respectively, and have the ability to impart important mechanical properties , e . g . mechanical reinforcement : both "nano" and "nano-structured" sp2carbon allotropes therefore have many diverse and large volume important applications .

[0013] In order to prepare a composite material that contains a sp2carbon allotrope, it is necessary to perform the mixing operation between the allotrope and the matrix o f the composite material in order to achieve a distribution and dispersion of the allotrope in said matrix .

[0014] In order to have a homogeneous distribution, the allotrope must be evenly distributed throughout the matrix of the composite material , whatever the state o f agglomeration and aggregation of the starting carbonaceous material . The fundamental spherical particles or layers o f carbon atoms of the allotrope aggregates must be dispersed in the matrix during mixing in order to have optimum dispersion .

[0015] However, it is well known how di f ficult it is to distribute and disperse graphitic materials , e . g . graphene , nano-graphites, fullerene, and to have a stable and homogeneous dispersion of graphitic layers in lipophilic matrixes, also in light of the fact that in some cases, e.g. cross-linking, the re-aggregation of graphitic layers occurs. See, for example, Galimberti, M., Cipolletti, V., Musto, S., Cioppa, S., Peli, G., Mauro, M., & Kumar, V.

[0016] (2014) . Recent advances in rubber nanocomposites . Rubber Chemistry and Technology, 87 (3) , 417-442, in which the preparation of elastomeric composites with a high surface area nanographite (HSAG) in synthetic isoprene rubber (poly ( 1 , 4-cis-isoprene ) ) is described.

[0017] The same mixing and re-aggregation problems in lipophilic matrixes are also reported in literature for other sp2carbon allotropes such as carbon nanotubes (CNTs) , carbon black.

[0018] The stability of sp2carbon allotropic dispersions in composite material matrixes is also a necessary condition for the composite material to be developed on an industrial scale .

[0019] One example is the coatings industry, where it is absolutely necessary to achieve homogeneous dispersions of carbonaceous materials, particularly carbon black. See, for example, Nsib, F., Ayed, N., & Chevalier, Y. (2006) Selection of dispersants for the dispersion of carbon black in organic medium. Progress in organic coatings, 55(4) , 303-310 .

[0020] One route taken to achieve better dispersion of sp2carbon allotropes is to functionalise said allotropes by introducing a speci fic type of substituent identi fied for the speci fic type of matrix under consideration . See the above-mentioned article .

[0021] Functionalisation reactions of sp2carbon allotropes can give rise to more or less labile bonds , i . e . covalent or suprammolecular bonds . In both cases , compounds are formed that can be defined as "adducts" . Covalent functionalisations form compounds that typically retain their chemical identity in the composite material and, once added to the composite material matrix, such adducts do not separate into their starting components . I f the functionalisation is supramolecular , the compound generally tends to separate into its components ( the substrate and the functionaliser ) in the composite material . This depends on the relative strength of the interactions between substrate , functionaliser and matrix .

[0022] In addition, the functionalisation of sp2carbon allotropes , hereafter also referred to as carbonaceous materials , appears to require speci fic chemical reactions , carried out with traditional chemical synthesis equipment , often using ingredients that are critical from the point of view of their impact on health and the environment , and also with the use of harsh process conditions.

[0023] Furthermore, it is known from literature that each functionalisation reaction introduces a specific type of substituent / functionaliser . That is, to introduce a certain type of functional group, a certain type of chemical reaction is required. It is therefore difficult to conceive of being able to use the same carbon allotropes, functionalised with the same type of chemical reaction, in matrixes having a different chemical nature (as they are destined for different sectors) but which have in common the fact of being a lipophilic matrix.

[0024] Therefore, in the field of composite materials having a lipophilic matrix and containing sp2carbon allotropes there is a highly perceived need for a method for preparing homogeneous dispersions of sp2carbon allotropes that are stable in any lipophilic matrix, in particular in lubricants (oils and / or greases) and waxy compounds, without the need for dispersants specific for the type of lipophilic matrix, so as to permit the widespread use of said sp2carbon allotrope dispersion in diverse fields but which have in common the use of a lipophilic matrix.

[0025] It would also be desirable to have a method as defined above that also allows for the preparation of a stable composite containing a high concentration of the dispersed carbonaceous material, e.g. around 1% by weight with respect to the weight of the lipophilic matrix but also greater than 1 % ( so-called masterbatch) , that is also homogeneously dispersible in the final lipophilic matrix o f the composite material so as to be employable as an additive .

[0026] It is there fore an obj ect of the present invention to provide a process for preparing composite materials comprising dispersions , concentrated or diluted, of sp2carbon allotropes in a l ipophilic matrix of a composite material , said process comprising the steps of

[0027] (A) Mixing, optionally in the presence of one or more solvents , a sp2carbon allotrope , in particular an allotrope having at least one dimension smaller than 100 nm, with a compound containing a pyrrole ring of formula

[0028] ( 1 ) wherein :

[0029] Ri and R2 are , independently o f each other, hydrogen or an alkyl group containing a number of carbon atoms ranging from 1 to 20, preferably 1 to 10, more preferably 1 to 5, even more preferably 1 to 2,

[0030] Ri, R2 preferably being an alkyl group as defined above ;

[0031] R3 is an unsubstituted linear or branched aliphatic group, with or without unsaturation, and not containing functional groups such as for example OH, C=O, said R3 containing a number of carbon atoms ranging from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, even more preferably from 6 to 20; or

[0032] R3is a polymer chain, preferably deriving from a polyamine, e.g. triethylenetetramine (TETA) , Diethylenetriamine (DETA) , and from polyisobutylene (DIB) and maleimide; or R3is a polymer chain composed of a polyetheramine containing a poly (oxyalkylene) chain, for example a jeffamine (5 8-Dimethyl-4 7 10- trioxatridecane-2r12-diamine) , said compound (i) being optionally obtained in situ in said step (A) by reaction of a 1,4-diketone with a primary amine R-NH2 having R=R3of the compound of formula (1) ;

[0033] (A' ) optionally removing one or more of said solvents, when present, to obtain a solid or semi-solid mixture;

[0034] (B) heating, preferably under stirring and / or mixing, the mixture comprising the sp2carbon allotrope and the pyrrole compound of formula (1) ;

[0035] (C) mixing, preferably under heating, the mixture obtained in step (B) with a compound of a lipophilic nature which constitutes the lipophilic matrix of a composite material to obtain a composite, preferably in the form of a paste, having a predetermined concentration of said sp2carbon allotrope in said lipophilic matrix; and optionally

[0036] (D) diluting, preferably by mixing, the composite obtained in step (C) with a compound of a lipophilic nature, equal to or different from that used in step (C) , to obtain a composite having a total concentration of said sp2carbon allotrope lower than the predetermined one obtained in step (C) .

[0037] The term "compound of a lipophilic nature which constitutes the matrix of a composite material" is understood here to identify the lipophilic matrix constituting the predominant component of a composite material in terms of concentration / quantity : the term "compound of a lipophilic nature" preferably excludes solvents such as toluene, heptane, xylene, hexane, ethyl acetate, acetone and isoprene rubbers (IR) , butadiene rubbers (BR) and the like.

[0038] In one embodiment of the invention, the compound of a lipophilic nature which constitutes the lipophilic matrix of the composite material is a compound having a molecular weight greater than 200 g / mol, and is not isoprene rubbers (IR) , butadiene rubbers (BR) and the like.

[0039] Steps (A) , (B) , (C) indicated above as separate steps conducted in sequence, can also be carried out

[0040] - all three simultaneously, adding the components (allotrope, pyrrole compound (i) and lipophilic matrix) individually in any order, under stirring. In this case the heating of step (B) may not be carried out if the mixing of step (C) causes the increase of temperature of the mixture thus heating it; or

[0041] - the first two steps (A) and (B) carried out simultaneously to obtain an addition product between the sp2carbon allotrope and the pyrrole compound (i) , which is then followed by step (C) in which the addition product, e.g. adduct, obtained from step (B) is mixed with the lipophilic matrix; without departing from the scope of the present invention.

[0042] Steps (A) and (B) conducted in sequence or simultaneously and before step (C) generally result in an addition compound in the form of an adduct with generally covalent bonds, although this is not binding for the purposes of the present invention. In fact, the term "adduct" is generally used to identify a compound obtained by means of an addition reaction, the components of which are bonded with more or less labile bonds ( supramolecular bonds or covalent bonds) , which can be obtained ex-ante in order to be used subsequently or be obtained in situ. In order to facilitate understanding of the examples in this description, the term "adduct" will be used to identify primarily the addition compound between allotrope and pyrrole compound (s) prepared ex-ante before being added to the lipophilic matrix, while the term "combination" , "mixture" of sp2carbon allotrope with pyrrole compound (i) will be used to indicate the fact that the allotrope and pyrrole compound (i) are added individually and simultaneously to the lipophilic matrix, irrespective of the type of covalent or supramolecular bond formed between the allotrope and the pyrrole compound (i) .

[0043] The existence of covalent or supramolecular bonds between the allotrope and the pyrrole compound (i) implies that the aforementioned components of the adduct are not individual as single elements. This can be indirectly verified by stability tests, XRD dif f ractograms and mechanical tests as will be detailed in the examples.

[0044] In a preferred embodiment, steps (A) , (B) and (C) are carried out simultaneously by adding, optionally while hot, the allotrope and the pyrrole compound (i) individually to the lipophilic matrix . This is advantageous mainly from an operational point of view ( one step one pot ) ; moreover, this mode can lead indif ferently to the formation of an adduct with covalent bonds between the components or of a product in which the allotrope and the pyrrole compound ( i ) have supramolecular bonds .

[0045] In accordance with the present invention, the singular indefinite article , "one" , is understood to also include the meaning of "at least one" , unless speci fied otherwise .

[0046] In the present description of the invention, unless otherwise speci fied, the values of the ranges include the extremes of the range .

[0047] In the present description of the invention, unless otherwise speci fied, the percentages ( % ) are to be understood by weight .

[0048] In the present description of the invention, the term " compri se" includes as a particular limiting case also its meaning as "consisting of" .

[0049] In the present description of the invention, the term " essentially consi sts of" means that

[0050] - the composition or method necessarily includes the listed ingredients or steps ; and that

[0051] - the composition or method is open to unlisted ingredients or unlisted steps that do not materially af fect the basic and innovative properties of the composition or method.

[0052] In the present description of the invention, unless otherwise specified, "part" and "parts" means part by weight and parts by weight, respectively. DESCRIPTION OF THE DRAWINGS

[0053] Figures 1-3 illustrate three samples, one of which was prepared in accordance with the invention, of different paraffinic wax composites as prepared in the examples which have been visually evaluated in terms of stability according to METHOD 3 as described in the characterisation of the examples;

[0054] Figure 4 shows the trend of the elastic shear modulus G' along with the variation of the strain % (strain!) of a sample of a sole EPM rubber and of three samples of different composites based on EPM (lipophilic matrix) as prepared in the examples, two of which were obtained in accordance with the invention;

[0055] Figures 5-8 illustrate X-ray diffraction spectra of the four dissimilar materials in Figure 4;

[0056] Figures 9-12 illustrate X-ray diffraction spectra of a sample of SBS and of three different samples of composites based on SBS as prepared in the examples, two of which were obtained in accordance with the invention.

[0057] DETAILED DESCRIPTION OF THE INVENTION

[0058] The compound of formula (i) to be used in step (A) of the process according to the present invention can be obtained by the Paal Knorr reaction between a 1,4-diketone of formula and a primary amine R-NH2 where the R group of the primary amine is equal to, or has the same meaning as, the R3 group of the compound of formula (1) .

[0059] For example, in the case of the compound of formula (i) having RI=R2=CH3, the Paal Knorr reaction takes place by reacting the 2 , 5-hexanedione and a primary amine R-NH2 (with R corresponding to, and having the same meaning as, R3) according to the following synthesis diagram known in the state of the art:

[0060] The primary amines R-NH2 that can be used to obtain the compound (i) defined above can be either aliphatic (with or without unsaturation) or polymeric.

[0061] Primary amines may include: Oleylamine (e.g. Armeen OL, industrial grade 95%) ;

[0062] - Dodecylamine (e.g. Commercial dodecylamine with industrial grade 98%) ;

[0063] - Octadecylamine, Stearylamine (e.g. commercial industrial grade 99%) ;

[0064] - PIBSI (polyisobutylene succinimide) is a primary polymeric amine obtained, for example, by reacting polyisobutylene (PIB) with maleic anhydride and the subsequent reaction with a polyamine, e.g. triethylenetetramine (TETA) .

[0065] In step (A) of the process of the invention, it is possible to mix the sp2carbon allotrope with compound (i) which has been prepared earlier in a step (AO) , or with compound (i) which is already available on the market, or to obtain said compound (i) in situ during the execution of the mixing step (A) , as will be explained in detail below, without thereby departing from the scope of the present invention .

[0066] In a preferred embodiment of the invention, compound (i) is already ready before step (A) is carried out because it has been prepared earlier in a step (AO) or is commercially available.

[0067] In an embodiment, the compound of formula (i) has an R3group chosen from an alkyl, alkenyl or alkynyl, aryl, alkyl-aryl, alkenyl-aryl , alkynyl-aryl group, and having a number of carbon atoms as defined above. Preferably R3 is an oleyl (monovalent oleic acid radical) , octadecyl, dodecyl, stearyl (monovalent stearic acid radical) group.

[0068] Preferred examples of the compound of formula (i) are:

[0069] 2 , 5-dimethyl-l-oleyl-lH-pyrrole (oleyl pyrrole, OP) of formula

[0070] 2 , 5-dimethyl-l -octadecyl- IH-pyrrole

[0071] (octadecylpyrrole, ODcP) of formula

[0072] 2, 5-dimethyl-l-dodecyl-lH-pyrrole (dodecylpyrrole,

[0073] DodcP) of formula

[0074] In a particular embodiment, the compound of formula (i) can also be a compound in which R3is a polymer chain, e.g. derived from a polylsobutylene Succinimide, which in turn can be derived from reactions between polyisobutylene (PIB) , maleic anhydride and a polyamine, e.g. triethylenetetramine (TETA) .

[0075] In particular, when R3is a polymer chain, the compound of formula (i) can have the following formula

[0076] PIBSI-P (Pyrrolo-Polylsobutylene Succinimide) with n=l-30.

[0077] The compound PIBSI-P is obtained by the reaction between a polyisobutylene succinamide and a triethylenetetramine or similar polyamine of the TETA type.

[0078] In another embodiment, when R3is a polymer chain, the compound of formula (i) can have the following formula (I) The latter compound of formula ( I ) is obtained according to the following reaction

[0079] (hexanedione )

[0080] In another embodiment , when R3i s a polymer chain, the compound of formula ( i ) can have the same formula as the above formula ( I ) but wherein R3i s the monovalent radical derived from the following compound

[0081] The Applicant has found that the combined use of the compound of formula ( i ) with the sp2carbon allotrope in the present process according to the invention, allows to obtain homogeneous and stable dispersions of sp2carbon allotrope , particularly in the case of nanographite and graphene , in various lipophilic matrixes , in particular in the matrixes constituted by lubricating oils and / or greases and waxy compounds. Without wishing to be bound to any theory, it can be assumed that the compatibility of nanographite and / or graphene in the lipophilic matrix is favoured by the interaction of the compound (s) with the edges of the lamellae composing the nanographite, graphene and sp2carbon allotropic analogues having at least one dimension less than or equal to 100 micron (nano) .

[0082] The sp2carbon allotropes that may be used in the present process of the invention include carbon black (CB) , graphene, nano-graphites consisting of a few graphene layers (from a few units to a few dozen) , high surface area nano-graphites (HSAG) , graphite or graphene with a number of graphene layers comprised between 2 and 10,000, fullerene, single-walled or multi-walled carbon nanotubes (CNTs) , nanotoroids, nanocones, graphene nanoribbons, or mixtures thereof.

[0083] Preferably, the sp2carbon allotrope is chosen from among allotropes used as "nano" fillers such as graphene, nano-graphites consisting of a few graphene layers (a few units to a few dozen) , high surface area nano-graphites (HSAG) , e.g. comprised between 100 and 400 m2 / g, graphite, graphene, fullerene, and carbon nanotubes or mixtures thereof .

[0084] In a particularly preferred embodiment, the sp2carbon allotrope is chosen from graphene, nano-graphites consisting of a few graphene layers (a few units to a few dozen) , graphite, graphene, high surface area nanographites (HSAG) , e.g. comprised between 100 and 400 m2 / g, preferably comprised between 250 and 350 m2 / g.

[0085] The sp2carbon allotropes that can be used in the present invention may also contain functional groups such as, for example, hydroxyls, epoxides, aldehydes, ketones, carboxylic acids, without departing from the scope of the present invention.

[0086] In an embodiment, the mixing step (A) can also be conducted in the presence of one or more solvents, generally having a low-boiling point, such as apolar solvents, protic or aprotic polar solvents, e.g. alcohols, ketones, esters, amides.

[0087] Examples of low-boiling point alcohols are ethanol and isopropanol; examples of low-boiling point ketones are acetone and methyl ethyl ketone, preferably acetone; an example of a low-boiling point ester is ethyl acetate; an example of a low-boiling point amide is N-methyl pyrrolidone. Examples of apolar solvents are hydrocarbon solvents such as hexane, heptane, cyclohexane, toluene.

[0088] A preferred example of a solvent for step (A) is acetone .

[0089] The solvent in step (A) can advantageously be used to form a suspension / dispersion of the sp2carbon allotrope and / or to form a solution / suspension of compound ( i ) .

[0090] In an embodiment , the present process according to the invention may involve performing step (A) by preparing a dispersion of the sp2carbon allotrope to which the primary amine and diketone defined above are added so as to form the pyrrole compound ( i ) in si tu in step (A) .

[0091] In another embodiment , the step (A) of mixing the allotrope with compound ( i ) can take place by adding the sp2carbon allotrope and compound ( i ) to the solvent under stirring .

[0092] The stirring in said step (A) of dispersion of the allotrope with the pyrrole compound may be conducted by, for example , sonication, mechanical stirring, magnetic stirring, in the presence or absence of one or more solvents as defined above , using suitable mixing means such as , for example , a planetary mixer, Silverson mixer, sonicator, speedmixer, ball mills and the like .

[0093] The mixing means used in step (A) can operate with a speed ranging from 1500 rpm to 6000 rpm, or with a speed ranging from 60- 80 rpm, or with a speed ranging from 100 rpm to 1500 rpm, depending on whether solvent is used or not .

[0094] Where one or more solvents and / or stirring are used in step (A) , the order of addition o f the compound of formula ( i ) and the sp2carbon allotrope with respect to the solvents and / or stirring is not binding for the purposes of the present invention.

[0095] In an embodiment of the invention, it is possible to carry out step (A) by first preparing a suspension of the sp2carbon allotrope in a first solvent, then stirring / sonicating said allotrope suspension and subsequently adding to said suspension, again under stirring / sonication, the compound (i) , possibly dissolved in a second solvent, said first and second solvents being the same or different from each other.

[0096] In another embodiment of the process according to the invention, step (A) is conducted by adding the sp2carbon allotrope and the compound of formula (i) to the solvent as defined above, under stirring / sonication.

[0097] If one or more solvents are used in step (A) , it is preferable to carry out the subsequent step (A' ) of removing one or more of the solvents at the end of the successful mixing of the sp2carbon allotrope with the chemical compound of formula (i) so as to subject to heating, in step (B) , a solid mixture, e.g. powdery, or semi-solid, e.g. paste-like consistency, substantially free from solvent and comprising the mixture of the sp2carbon allotrope and the chemical compound of formula (i) .

[0098] The removal of one or more solvents in the optional step (A' ) can be carried out by methods known in the art such as evaporation, vacuum evaporation and the like.

[0099] The heating in step (B) takes place at a temperature generally comprised between 80-100°C and 170°C, preferably between 130°C and 170°C, more preferably between 130°C and 160°C, even more preferably around 150°C.

[0100] The heating temperatures of step (B) may be higher or lower than those used in step (C) of this process, preferably higher, depending on whether the process steps are conducted in sequence or simultaneously and on the type of lipophilic matrix.

[0101] Generally, the mixing step (C) with the lipophilic matrix takes place hot, particularly when the compound that can be used as a lipophilic matrix is solid at room temperature, e.g. waxes, semi-crystalline polymers, rubbers .

[0102] Step (C) is advantageously conducted under heating if the lipophilic matrix is in a solid physical state at room temperature, and thus heating takes place by operating at a temperature that depends primarily on the temperature at which the lipophilic matrix is in such a liquid or molten state as to facilitate the mixing thereof with the remaining components of the composite material.

[0103] In an embodiment, the heating step (C) is carried out by operating at a temperature of at least 80-100°C.

[0104] If step (C) is carried out at the same time as steps (A) and (B) so that the sp2carbon allotrope is mixed with the chemical compound of formula (i) and the lipophilic matrix at the same time, it is advantageous to carry out heating while mixing at a temperature that can range from 80°C to 150°C.

[0105] The heating indicated in steps (B) , (C) can be carried out by methods known in the art, for example by the use of oil baths, electric coils, electric plates, thermal fluids, irradiation with photons and the like, without departing from the scope of the present invention.

[0106] In the event that steps (A) , (B) and (C) are conducted separately in sequence, the heating in step (B) of the mixture comprising the sp2carbon allotrope and compound (i) is carried out from 50 to 150 minutes, preferably 100 to 140 minutes, more preferably 115 minutes to 125 minutes.

[0107] In the event that steps (A) , (B) and (C) are conducted simultaneously, the heating is carried out during the simultaneous mixing of the three components (allotrope, pyrrole compound and lipophilic matrix) from 130 minutes and 220 minutes, preferably between 150 minutes and 200 minutes, more preferably between 170 minutes and 190 minutes .

[0108] In step (C) , mixing between the lipophilic matrix, and the allotrope and pyrrole compound (i) , in individual or adduct form, can be carried out using the same mixing methodology and mixing means as in step (B) .

[0109] In particular, in step (C) , mixing under stirring can take place using, for example, a mixer operating at an rpm ranging from 1500 rpm to 6000 rpm, e.g. Silverson, or a mixer operating at around 60-80 rpm, e.g. Brabender, depending on the type of lipophilic matrix.

[0110] Mixing means that can advantageously be used in step (C) are, for example, Silverson mixer, Brabender® type internal mixer, depending on the viscosity and nature of the chosen lipophilic matrix and the temperature at which step (C) is carried out.

[0111] The compound of a lipophilic nature that makes up the lipophilic matrix of a composite material can be, for example, one or a combination of several compounds chosen from among:

[0112] - lubricating oils or base oils of mineral, synthetic or renewable raw material origin, used in lubricating compositions ;

[0113] - lubricating greases;

[0114] - solid compounds at room temperature (hereinafter also referred to as waxy compounds) , such as paraffinic waxes, animal waxes, vegetable waxes such as hydrocarbon compounds, saturated fatty acids, esters, e.g. methyl esters, of saturated fatty acids with a number of C atoms greater than or equal to C12 up to 32, e.g. esters of myristic, palmitic, lauric, stearic, hexacosanoic and similar acids, also known as "waxes", "paraffinic waxes" whose molecules have alkyl chains with a number of carbon atoms greater than or equal to 12 up to 32;

[0115] - polymeric matrixes, for example elastomers (e.g. gaskets, rubbery materials) , in particular "EPR / EPM" (rubbers based on ethylene - propylene copolymers) and typical block copolymers called SBS

[0116] (styrene / butadiene / styrene) ;

[0117] - combinations thereof.

[0118] Base oils can be chosen from mineral, synthetic, vegetable, animal and mixtures thereof.

[0119] Oils of mineral origin come from well-known crude oil refining processes such as, for example, distillation, deparaf f inization, deasphalting, dearomatization and hydrogenation .

[0120] Oils of synthetic origin preferably include hydrocarbon oils such as, for example, polymerized and hydrogenated terminal or internal olefins; alkylbenzenes; polyphenyls; alkylated diphenyl ethers; polyalkylene glycols and derivatives, where the terminal hydroxyl groups have been modified for example by esterification or etherification.

[0121] Another class of synthetic lubricant oils preferably comprises esters of carboxylic acids, either synthetic or of animal or vegetable derivation with a variety of alcohols or polyols.

[0122] A further class of synthetic lubricant oils preferably comprises the esters of carbonic acid with a variety of alcohols and polyols.

[0123] Preferably the vegetable oils are selected from soy, palm and castor oils, whereas the oils of animal origin are preferably selected from suet, lard or whale oil.

[0124] Another method for the classification of the base oils is the one defined by the American Petroleum Institute (API) in the publication "Engine Oil Licensing and Certification System" (API EOLCS, 1507 - Industry Services Department, Fourteenth Edition, December 1996, Addendum 1, 2014 and annex and March 2015 Version) .

[0125] The base oils are divided into five groups as a function of their chemical / physical and compositional characteristics. According to this classification, base oils that can be used in the lubricant formulations covered by the present invention can belong to all of the aforementioned API Groups, preferably to API Groups II, III, IV, V, and even more preferably to API Groups III, IV and V.

[0126] Lubricating greases that can be used in the present invention as a lipophilic matrix can be lubricating greases comprising a base oil as defined above and at least one main thickener / thickening agent, having different consistency according to the NLGI scale.

[0127] The solid compounds at room temperature (T= 15-25°C) that can be used as a lipophilic matrix in the present process according to the invention are generally waxy compounds, e.g. waxes, characterised by the following properties : a) Malleability at room temperature b) Low viscosity when molten c) Insolubility in water and water repellency.

[0128] Classes of waxes suitable for the purpose of the invention may be of different origins, e.g. mineral or synthetic, animal, vegetable, or mixtures thereof.

[0129] Examples of waxes of mineral or synthetic origin include paraffins, consisting mainly of pure alkanes, preferably long chain linear or blended; microcrystalline wax; polyethylene or poly alpha-olefin waxes; Fisher- Tropsch wax; and amide waxes (e.g. stearamide or oleamide) , or mixtures thereof.

[0130] Examples of waxes of animal origin include beeswax, lanolin or "Chinese wax" or mixtures thereof.

[0131] Examples of vegetable waxes include carnauba wax, myrtle wax, castor wax, esparto wax, jojoba wax or mixtures thereof .

[0132] Other examples of waxy compounds can be PCMs (Phase change materials) having a melting temperature (Tm) than ranges from 70°C to 120°C; hexadecane (Tm around 18°C) ; stearic acid (Tm around 69°C) ; myristic acid (Tm around 54°C) ; palmitic acid (Tm around 63°C) , or mixtures thereof.

[0133] Examples of polymer matrixes are amorphous or semicrystalline polymers, such as polyurethanes, polyamides, polyethers, polyesters, polycarbonates, poly ( vinylesters ) , poly ( vinylalcohol ) , copolymers of ethylene with vinylacetate or vinyl ( alcohol ) , polyolefins, such as poly ( ethylene ) and poly (propylene ) , ethylene-propylene copolymers, polymers derived from dienes, natural rubber, i.e. poly (1, 4-ci s-isoprene) , copolymer of styrene and butadiene .

[0134] In a preferred embodiment, the lipophilic matrix is chosen from

[0135] - Base oil, preferably belonging to the Group 3 class (e.g. ETRO 4) ;

[0136] - Ethylene-Propylene Copolymer EP(D)M, e.g. Dutral CO 054;

[0137] - Styrene-Butadiene-Styrene (SBS) linear block copolymer, e.g. Europrene SOL TH 2312;

[0138] - Paraffinic wax, preferably mixture of paraffinic waxes, e.g. Paramat. wax;

[0139] - combinations thereof, e.g. etro 4 base oil + SBS.

[0140] In a particularly preferred embodiment, the lipophilic matrix is a lubricant base oil or lubricating grease.

[0141] In another preferred embodiment, the lipophilic matrix is a paraffin wax.

[0142] Optionally, a surfactant comprising a compound containing sp2hybridised carbon atoms, preferably a polymeric surfactant, can be added to the mixture in step (C) .

[0143] Examples of polymeric surfactants include polar surfactants, non-polar surfactants or mixtures thereof.

[0144] Examples of surfactants that can be used in the process of the present invention are:

[0145] - Star-shaped polymer with approximately 16 polymer arms which consist of a hydrogenated styrene isoprene copolymer (e.g. SV261) ;

[0146] - Polymer with Pour Point Depressant characteristics obtained by combining alkyl methacrylic monomers (Mw 200000 Da) , e.g. HV32;

[0147] - Anionic oligomeric dispersant suitable for use in both solvent-based and water-based systems (e.g. KD24) ;

[0148] - dispersant based on Phosphoric ester and PEG (e.g. S23B) ;

[0149] - Polymeric dispersing additive consisting of polybutylene succinate and methylene bisisocyanate with the presence of PEG (e.g. S624) ;

[0150] - Non-ionic polymeric dispersant for dispersions which are based on solvents for advanced ceramics, electronic materials and nanomaterials (e.g. KD 14) ; Non-ionic surfactant derived from polyethoxylated sorbitan and oleic acid (e.g. SPAN 80) ;

[0151] - Hydrogenated styrene butadiene linear block copolymer with 30% styrene content (e.g. XLZ 18 A) .

[0152] In an embodiment, the surfactant is a non-polar surfactant compound.

[0153] In a preferred embodiment, the dispersants are chosen from SV261, HV 32, or combinations thereof.

[0154] In another embodiment, the compound of formula (i) defined above PIBSI-P is used in the process according to the invention in combination with a second compound of formula (1) .

[0155] According to a preferred embodiment of the process of the present invention, steps (A) , (B) , (C) are carried out simultaneously. In this preferred embodiment, at least one surfactant comprising a compound containing sp2hybridised carbon atoms is optionally added to the mixture of the sp2carbon allotrope and the pyrrole compound of formula (1) .

[0156] The predetermined concentration of the sp2carbon allotrope in the lipophilic matrix (even when made up of a mixture of different lipophilic matrixes) of the composite material obtained from step (C) is not binding for the purposes of the present invention. This predetermined concentration (e.g. in phm, where phm means per hundred parts of lipophilic matrix) may generally be in the range from

[0157] 0 . 5-50 phm,

[0158] - preferably between 1-35 phm, the lipophilic matrix may be a base oil , waxy compound, elastomer, lubricating grease or another type of matrix as defined above or mixtures thereof , preferably base oil , wax, lubricating grease as defined above .

[0159] In an embodiment , the predetermined concentration of the sp2carbon allotrope in the lipophilic matrix of the composite material obtained from step ( C ) may be greater than or equal to 10 phm up to 30-35 phm . In this case , we may talk about concentrated composites that can then be diluted or dispersed in the lipophilic matrix by carrying out step D) , without thereby departing from the scope o f the present invention .

[0160] In another embodiment , the prefixed concentration o f the sp2carbon allotrope in the lipophilic matrix of the composite material obtained from step ( C ) can vary in the range of 2-22 phm .

[0161] The amount of pyrrole compound of formula ( i ) used in relation to the amount of sp2carbon allotrope used to obtain the prefixed concentration is in the range from 3 phc to 50 phc (per hundred carbon, considering 100 phc to be the amount (by weight ) of allotrope used to obtain the aforementioned prefixed concentration . In an embodiment, the amount of pyrrole compound of formula (i) used with respect to the sp2carbon allotrope is comprised in the range of 5 phc to 10 phc .

[0162] In another embodiment, the amount of pyrrole compound of formula (i) used with respect to the sp2carbon allotrope is comprise in the range from 10 phc to 37 phc.

[0163] In the event that steps (A) , (B) are carried out in sequence to form an adduct to be added later in step (C) , this adduct can be added to the lipophilic matrix in quantities comprised between 10 phm and 50 phm.

[0164] The amount of surfactant (compound containing hybridised sp2carbon atoms) that can be used in addition to the mixture of sp2carbon allotrope and pyrrole compound of formula (i) is comprised between

[0165] - 5 phc and 50 phc,

[0166] - preferably between 10 phc and 30 phc,

[0167] - more preferably between 15 and 20 phc, where phc means "per hundred carbon parts" being 100 phc the amount (by weight) of the sp2carbon allotrope.

[0168] When the surfactant is used, the maximum value of the sum of the quantities of pyrrole compound (i) + surfactant, hereafter also referred to as "organic substance" is equal to 50 phc, preferably the maximum value of organic substance being 30 phc, the minimum value of organic substance being 8 phc. In an embodiment, the pyrrole compound is present in quantities of at least 15 phc, preferably at least 30 phc, in the absence of surfactant.

[0169] In another embodiment, the pyrrole compound is present in an amount of at least 15 phc and the surfactant is present in an amount of at least 15 phc.

[0170] In the event that step (C) is carried out separately and after steps (A) and (B) sequentially, the mixture of the sp2carbon allotrope with the chemical compound of formula (i) is heated in step (B) of the process of the invention in a temperature range between 100°C and 170°C, preferably between 130°C and 170°C, even more preferably between 140°C and 160°C.

[0171] In the event that steps (A) , (B) , (C) are carried out separately, the mixture of the sp2carbon allotrope with the chemical compound of formula (i) , for the formation of the adduct, is heated in step (B) of the process in a time interval between 50 minutes and 150 minutes, preferably between 100 minutes and 140 minutes, even more preferably between 115 minutes and 125 minutes (the time that is usually used is 120 minutes) .

[0172] If steps (A) , (B) and (C) are carried out simultaneously, the system is heated to a temperature range between 100°C and 170°C, preferably between 130°C and 170°C, even more preferably between 140°C and 160°C. In the event that steps (A) , (B) , (C) are carried out simultaneously, the mixture of the sp2carbon allotrope with the chemical compound of formula (i) , for the formation of the adduct, is heated in step (B) of the process in a time interval between 130 minutes and 220 minutes, preferably between 150 minutes and 200 minutes, even more preferably between 170 minutes and 190 minutes.

[0173] The composite materials obtained from step (C) with this process can be regarded as concentrated composite materials in terms of allotrope content and, due to their high stability, can be used in various fields as additives or as composite materials as such.

[0174] For example, the concentrated composite materials containing base oil and comprising the allotrope and pyrrole compound (i) described above, which are obtainable from step (C) of the present process, can be used as soluble "metal free" additives to be added to base oils (lipophilic matrix) in the preparation of lubricating compositions in the form of lubricating oils or greases in order to impart anti-friction and anti-wear properties to said lubricating compositions.

[0175] The composite materials based on waxy compounds (lipophilic matrix) and containing sp2carbon allotropes and the pyrrole compound (i) described above, which are obtainable in accordance with the present invention, can be used as cooling means for passive cooling of photovoltaic panels due to the thermal conductivity of such composites .

[0176] Composite materials which are obtainable from step ( C ) of the process in accordance with the present invention and are based on elastomers such as SBS , EPM, also containing sp2carbon allotropes and the pyrrole compound ( i ) as described above , , can be used as masterbatch additives to impart mechanical strength to gaskets , rubbery materials , coatings and generally to all elastomeric materials .

[0177] The above-mentioned additives are themselves stable over time , e . g . 120 hours , and this stability is an indication of the fact that the nanographite is exfoliated in the presence of the pyrrole compound according to the present preparation method, and does not tend to aggregate , whereas in the absence of the pyrrole compound, the nanographite shows aggregation due to the instability o f the composite .

[0178] This tendency towards non-aggregation has been observed in distinct types of lipophilic matrix . See the examples .

[0179] The present method and the composite materials obtainable or obtained from it have many advantages .

[0180] A first advantage lies in the use of allotrope functionalising compounds that are not critical from the point of view of health and environmental impact .

[0181] A second advantage lies in the use of process conditions that are not harsh, without the use of allotrope-speci fic dispersants depending on the di f ferent chemical nature of the lipophilic matrix .

[0182] A further advantage lies in the use of a single type o f allotrope functionalising agent for any type o f lipophil ic matrix, thus enabling the widespread use of said dispersion of sp2carbon allotropes in a variety of sectors that have lipophilic matrixes in common .

[0183] Another advantage lies in being able to prepare a stable , homogeneous composite containing a high concentration of the dispersed carbonaceous material , the so-called masterbatch, which is also homogeneously dispersible in the final lipophilic matrix of the composite material , e . g . base oil , elastomers , and also stable once diluted / dispersed in the final lipophilic matrix .

[0184] Some illustrative but not limiting examples of the present invention follow .

[0185] EXAMPLES

[0186] CHARACTERISATION METHODS

[0187] Stability test , by visual observation , of dispersions of nanographite , pyrrole compound and an optional surfactant in oil , at a nanographite concentration of 10 phm with respect to the oil considered 100 phm (concentrated composites , otherwise also defined as

[0188] "paste" ) (METHOD 1 ) The stability of the concentrated composite samples

[0189] (masterbatch) was investigated by keeping these samples under static conditions inside 50 ml Falcon™ (Corning) conical centrifuge tubes. The stability was assessed by measuring the height of the area with uniform blackest colour and the total height of the composite with a ruler with a millimetre scale after 24, 48, 120 and 216 hours. The height % of the composite showing the blackest uniform colour is calculated using the following equation:

[0190] 100 x (height of composite with blackest uniform colour) / (total height of composite)

[0191] The stability assessment is carried out by reporting "YES" and "NO" in Table 5.

[0192] "YES" is reported when the height of the dark area is > 98% of the initial height (see Table 5) .

[0193] - Stability test, by visual observation, of dispersions of nanographite, pyrrole compound and an optional surfactant in oil (concentrated composites, otherwise also defined as "paste") , diluted in oil at a concentration less than or equal to 0.1 vpasta / vfinaie% (paste vol / total vol of the diluted composition) (METHOD 2) :

[0194] The stability was investigated by keeping the composite samples under static conditions inside 50 ml Falcon™ ( Corning) conical centri fuge tubes , and performing a periodic visual check of the tube bottom . Physically, the tube was placed "upside down" to assess the presence of black composite deposit on the bottom .

[0195] - Stability test of composites based on paraffinic wax and adduct / combination of nanographite with pyrrole compound (Method 3) :

[0196] Wax-based composites containing nanographite with pyrrole compound were kept at 150 ° C ( in an oil bath) for 6 hours in a graduated cylinder . Removing the oil bath, the materials were then left to cool down to room temperature . Once room temperature was reached, the total height of the composite and the height of the composite showing the blackest uni form colour were measured using a ruler with a millimetre scale .

[0197] The height % of the composite showing the blackest uni form colour is calculated using the following equation : 100 x (hei ght of composi te wi th blackest uniform colour) / (total hei ght of composi te) .

[0198] The dispersion is considered stable i f the calculated height is 1 90 % of the initial height .

[0199] - Rheological characterisation of EPR-based composites and adduct / combination of nanographite with pyrrole compound by means of dynamic-mechanical shear tests (METHOD 4 ) : The rheological characterisation of elastomeric composites based on EPR and combination / adduct of nanographite and pyrrole compound (i) was carried out using an RPA (Rubber Process Analyser) rheometer.

[0200] The protocol followed for the rheological characterisation by means of annealing and strain-sweep tests is as follows: a first strain-sweep is performed at 60°C to cancel the previous thermo-mechanical history, between 0.2% and 100% as strain amplitude at a frequency of 1Hz, then an annealing test is performed again at 60°C for 15 minutes, keeping the strain at 0.2%, finally a second strain-sweep is performed, between 0.2% and 100% as strain amplitude at a frequency of 1Hz .

[0201] The elastic shear modulus G' was then measured as a function of strain amplitude.

[0202] The curves describing the dependence of the elastic modulus G' on the strain amplitude are shown in Figure 4.

[0203] The reduction in shear modulus G' at minimum strain and the difference AG' between the shear modulus values G' at minimum and maximum strain in the elastomers are associated with the reduction in the amount of lattice formed by the allotrope as reported in the literature, e.g. in Warasitthinon, N., Genix, A. C . , Sztucki, M., Oberdisse, J., & Robertson, C. G. (2019) . The Payne effect: Primarily polymer-related or filler-related phenomenon?. Rubber Chemistry and Technology, 92 (4) , 599-611.

[0204] - X-ray diffractometry of EPR and SBS as such and of EPR- and SBS-based composites containing adduct / combination of nanographite with pyrrole compound (Method 5) : Wide-angle X-ray diffraction (WAXD) patterns were performed in reflection, with a Bruker D8 Advance automatic diffractometer, with nickel-f iltered Cu-Ka radiation .

[0205] Since the diffraction angles of the peaks are 20, the patterns were recorded using a 20 range comprised between 4.7° and 90°. The spectra obtained were processed using MATLAB. X-ray analyses were performed by irradiating two orthogonal portions of each sample.

[0206] Each dif f ractogram (Figures 5, 6, 7, 8) therefore refers to the same sample which, irradiated at different intensities in two different orthogonal positions, produces two different dif fractograms (red line and blue line) whose trends are substantially similar.

[0207] - NMR Analysis:

[0208] It was conducted using a Bruker AV 400 spectrometer operating at 400 MHz (Bruker, Rheinstetten, Germany) and using deuterated chloroform (CDCI3) as a solvent.

[0209] MATERIALS

[0210] - Nanographite: HSAG nano24 graphite marketed by Asbury Carbon and having a surface area of approximately 350 m2 / g;

[0211] - EPR=Ethylene-Propylene copolymer elastomer, marketed by Versalis under the name Dutral CO 054 (EP(D)M) ;

[0212] - SBS= Styrene-Butadiene-Styrene Linear Block Copolymer, marketed under the name Europrene SOL TH 2312 by Versalis;

[0213] - Etro 4+ oil= Group 3 base oil, marketed by Petronas, with density=0.8348 kg / L;

[0214] - Paraffin wax= Mix of paraffin waxes, marketed by VWR Chemicals under the name Paramat; - Hexanedione= by Sigma-Aldrich, marketed by Merck (CAS

[0215] 110-13-4)

[0216] - Surfactants

[0217] EXAMPLES 1-3: Preparation of different pyrrole compounds of formula (i)

[0218] EXAMPLE 1: Synthesis of oleyl pyrrole (OP, 2,5- dimethyl- 1 -oleyl- IH-pyrrole )

[0219] 2 g oleylamine (leg., 5.23 mmol) and 597 mg 2,5- hexanedione (leg., 5.23 mmol) were poured into a 50 mL flask. Everything was placed under magnetic stirring for Ih at 130°C. After this time, the reaction mixture was cooled to room temperature. The pure product was obtained with a yield of 95%.

[0220] Below are the1H-NMR and13C-NMR data on the successful synthesis of oleyl pyrrole.

[0221] !H NMR (CDC13, 400 MHz) ; 5 (ppm)=5.81 (s, 2H, CH) , 5.55 (m, 2H, CH=CH) , 3,89-3, 87 (t, 2H, N- CH2-CH2- ) , 2,40 (s, 6H, CH3) , 2,20 (m, 4H, CH2-CH=CH-CH2) , 1,79 (m, 2H, N- CH2-CH2-R) , 1.49 (m, 22H, R-CH2-R) , 0.95 (m, 3H, CH3) .

[0222] 13C NMR (CDC13, 100 MHz) ; 5 (ppm) = 130.6, 127.6, 105.6, 43.72, 33.7, 32.01, 31.10, 29.78, 29.3, 27.5, 22.76, 14.16, 12.51.

[0223] Example 2: Synthesis of dodecyl pyrrole (DodcP, 2,5- dimethyl-1 -dodecyl- IH-pyrrole)

[0224] 16.24 g dodecylamine (1 eq., 87.61 mmol) and 10 g 2,5- hexanedione (1 eq., 87.61 mmol) were poured into a 250 mL flask. Everything was placed under magnetic stirring for 2 h at 130°C. After this time, the reaction mixture was cooled to room temperature. The pure product was obtained with a yield of 92%.

[0225] The1H-NMR and13C-NMR data on the successful synthesis of oleyl pyrrole are provided below.

[0226] !H NMR (CDC13, 400 MHz) ; 5 (ppm)=5.81 (s, 2H, CH) ,

[0227] 3.87- 3, 89 (t, 2H, N-CH2-CH2-) , 2.41 (s, 6H, CH3) , 1.80 (m, 2H, N-CH2-CH2-CH2-R) , 1.49 (m, 18H, CH2) , 0.95 (m, 3H, CH3) .

[0228] 13C NMR (CDC13, 100 MHz) ; 5 (ppm) = 127.27, 105.03,

[0229] 43.72, 32.01, 31.10, 29.78, 27.05, 22.76, 14.16, 12.51.

[0230] Example 3: Synthesis of octadecyl pyrrole (ODcP; 2,5- dimethyl-1 -octadecyl- IH-pyrrole) 0.5 g octadecanamine (1.85 mmol) and 0.2 g 2,5- hexanedione (1.85 mmol) were poured into a 10 mL glass vial equipped with a magnetic stirrer. The mixture was left stirring at 130°C for 3 h. The reaction time was chosen on the basis of the literature on the synthesis of pyrrole compounds at similar temperatures. After this time, the reaction mixture was cooled to room temperature. The pure product was obtained with a yield of 0.518 g (73%) .

[0231] Below are the1H-NMR and13C-NMR data on the successful synthesis of octadecyl pyrrole.

[0232] !H NMR (CDC13, 400 MHz) ; 5 (ppm) =5.81 (s, 2H, CH) ,

[0233] 3.78-3.74 (t, 2H, N-CH2-CH2- ) , 2.27 (s, 6H, CH3) , 1.66 (m, 2H, N-CH2-CH2-CH2-R) , 1.37 (m, 2H, CH2-CH3) 1.33 (m, 12H, CH2) , 0.95 (m, 3H, CH3) .

[0234] 13C NMR (CDC13, 100 MHz) ; 5 (ppm) = 127.27 , 105.03,

[0235] 43.72, 32.01, 31.10, 29.78, 27.05, 22.76, 14.16, 12.51.

[0236] Example 3a: Synthesis of pyrrole compound (i) having an R3polymeric chain (PIBSI-P) of formula

[0237] In an Erlenmeyer flask containing 850 mL of xylene, with mild heating and magnetic stirring 200.535g of PIBSI 1300-HEPA were dissolved of formula and molecular weight 1665 g / mol (1300 (PIB) + 98 (maleic anhydride) + 285 (HEPA) - 18 (H2O) ) .<

[0238] Then the contents of the flask were transferred into a 2L round-bottom flask equipped with magnetic stirrer and Dean-Stark trap, washing the beaker with an additional 50 mL of solvent (xylene) .

[0239] The reaction mixture was brought to a temperature of 110°C, then 16 mL of hexanedione (~15.58g, 0.136 moles) was added by dripping with a syringe.

[0240] The temperature was raised to 140°C to reflux and maintained as such for 7 hours, then heated for a further 8 hours the next day to 145°C until the theoretical amount of water was collected in the Dean-Stark trap (~4 ml) .

[0241] EXAMPLES 4-6: Preparation of adducts / combination of pyrrole compounds and nanographite

[0242] Example 4: Synthesis of the Nanographite / Oleyl pyrrole (OP) adduct

[0243] 85 mL of acetone is placed in a 250 mL round-bottom flask. 1 g of HSAG nano24 graphite (14 mmoles; molecular weight 72) is added to acetone , under magnetic stirring and, subsequently, 0.3 g (0.87 mmoles; molecular weight 345) of Oleyl Pyrrole (OP, ) prepared in example 1 are also added .

[0244] The above mixture is brought from room temperature to 90°C. After the acetone has completely evaporated, again under magnetic stirring, the temperature is raised to 180°C and kept constant for 2 h.

[0245] After this time, the mixture was placed in a sintered glass Buchner funnel (Buchner filter) for thorough washing with acetone and then the mixture was recovered and weighed, recovering 90-95% of adduct. In such a mixture, the OP is 30 phc with respect to the nanographite.

[0246] Example 5: Synthesis of the nanographite / dodecyl pyrrole DodcP adduct

[0247] In a 50 mL round-bottom flask, HSAG nano24 (200 mg, 2.8 mmol, molecular weight 71.42) and acetone (15 mL) were placed in sequence. The suspension was sonicated for 15 minutes, using a 2 L ultrasonic bath.

[0248] 0.28 mmol of dodecyl pyrrole (5 mL) was added to 5 mL of acetone. The resulting suspension was sonicated for 15 minutes. The solvent was removed under reduced pressure.

[0249] The HSAG / DodP black powder was poured into a 25 mL round-bottom flask equipped with a magnetic stirrer and heated to 180°C for 2 h.

[0250] After this time, the mixture was placed in a sintered glass Buchner funnel (Buchner filter) for thorough washing with acetone and then the mixture was recovered and weighed, recovering 90-95% of adduct.

[0251] Example _ 6 : _ Synthesis _ of _ the _ adduct nanographite / octadecyl pyrrole (ODcP)

[0252] Example 5 was repeated with the exception that octadecyl pyrrole was added as a compound of formula (i) instead of dodecyl pyrrole.

[0253] EXAMPLES 7-17: Preparation of concentrated lubricating oil-based composites comprising nanographite and a pyrrole compound, and stability test of the composites (METHOD 1)

[0254] Example 7 (comparative) : Preparation of a composite with Etro 4 oil and Nanographite

[0255] 10g of HSAG Nanographite and 100ml of Etro 4 oil (83.48 g) are added to a 150 ml beaker.

[0256] The mixture is heated to 150°C and mixed using a Silverson mixer at 5700 rpm for 3 hours. Table 4 shows the composition .

[0257] The mixture was then tested for composite stability by applying Method 1, the results of which are shown in Table

[0258] 5.

[0259] Example 8: Preparation of a composite with Etro 4 oil and nanographite / oleyl pyrrole combination added individually to the lipophilic matrix

[0260] 10 g of HSAG Nanographite, 3 g of Oleyl pyrrole obtained in Example 1 and 100 ml of Etro 4 oil (83.48 g) are added to a 150 ml beaker.

[0261] Everything is heated to 150°C and mixed using a Silverson mixer. First the mixture is maintained at 1800 rpm for 2h and then at 5700 rpm for Ih. Table 4 shows the composition .

[0262] The mixture was then tested for composite stability by applying METHOD 1, the results of which are shown in Table 5.

[0263] Example 9: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant (SV261)

[0264] 10 g of HSAG Nanographite, 1.5 g of Oleyl pyrrole obtained in Example 1, 1.5 g of surfactant SV261 and 100 ml of Etro 4 oil (83.48 g) are added to a 150 ml beaker.

[0265] The mixture is heated to 150°C and mixed using a Silverson mixer. First the mixture is maintained at 1800 rpm for 2h and then at 5700 rpm for Ih. Table 4 shows the composition .

[0266] The mixture was then tested for composite stability by applying Method 1, the results of which are shown in Table 5.

[0267] Example 10: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant (HV32 )

[0268] Example 9 was repeated, using the same quantities of components , with the exception that surfactant HV32 was used instead of surfactant SV261 . Table 4 shows the composition .

[0269] The mixture was then tested for composite stability by applying METHOD 1 , the results o f which are shown in Table 5 .

[0270] Example 11 : Preparation of a composite with Etro 4 oil , Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant (KD24 )

[0271] Example 9 was repeated, using the same quantities o f components , with the exception that surfactant KD24 was used instead of surfactant SV261 . Table 4 shows the composition .

[0272] The mixture was then tested for composite stability by applying METHOD 1 , the results o f which are shown in Table 5 .

[0273] Example 12 : Preparation of a composite with Etro 4 oil , Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant ( S23B )

[0274] Example 9 was repeated, using the same quantities of components , with the exception that surfactant S23B was used instead of surfactant SV261 . Table 4 shows the composition .

[0275] The mixture was then tested for composite stability by applying METHOD 1, the results of which are shown in Table 5.

[0276] Example 13: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant (S624)

[0277] Example 9 was repeated, using the same quantities of components, with the exception that surfactant S624 was used instead of surfactant SV261. Table 4 shows the composition .

[0278] The mixture was then tested for composite stability by applying METHOD 1, the results of which are shown in Table 5.

[0279] Example 14: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant (KD14)

[0280] Example 9 was repeated, using the same quantities of components, with the exception that surfactant KD14 was used instead of surfactant SV261. Table 4 shows the composition .

[0281] The mixture was then tested for composite stability by applying METHOD 1, the results of which are shown in Table 5.

[0282] Example 15: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant (SPAN80)

[0283] Example 9 was repeated, using the same quantities of components, except that surfactant SPAN80 was used instead of surfactant SV261. Table 4 shows the composition.

[0284] The mixture was then tested for composite stability by applying METHOD 1, the results of which are shown in Table 5.

[0285] Example 16: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and a second pyrrole compound (PIBSI-P)

[0286] Example 9 was repeated, using the same quantities of components, with the exception that a second pyrrole compound prepared in Example 3a (PIBSI-P) was added in place of the surfactant SV261. Table 4 shows the composition .

[0287] The mixture was then tested for composite stability by applying Method 1, the results of which are shown in Table 5.

[0288] Example 17: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination added individually to the lipophilic matrix and surfactant (XLZ 18A)

[0289] Example 9 was repeated, using the same quantities of components, except that surfactant XLZ 18A was used instead of surfactant SV261. Table 4 shows the composition.

[0290] The mixture was then tested for composite stability by applying Method 1, the results of which are shown in Table 5.

[0291] Table 4

[0292] Table 5: stability of concentrated composites from Examples

[0293] 7-17 (METHOD 1)

[0294] By comparing the stability data of comparative example

[0295] 7 with those of example 8 in accordance with the invention, it can be observed that the presence of the pyrrole compound of formula ( i ) determines the stability of the nanographite dispersion in lubricating oil as a lipophil ic matrix, and consequently the stability of the concentrated composite in oil .

[0296] Such stability of the composites o f the invention is an indication of the fact that the nanographite exfol iated during preparation does not shows aggregation in the lipophilic matrix when in the presence of the pyrrole compound, whereas in the absence of the pyrrole compound the nanographite shows aggregation since the height of the darker area in the specimen is much lower leaving a lighter upper area relative to the lipophilic matrix, indicative of a biphasic system .

[0297] In addition, it is noted that , regardless of the type of surfactant used, the presence of the pyrrole compound provides the composites of the invention in oil with a stability of up to 120 hours ( 5 days ) .

[0298] EXAMPLES 18-23 : dilution in lubricating oil of the previously prepared composites in oil and stability test Example 18: Dilution with Etro 4 oil of a composite containing Nanographite / oleyl pyrrole combination, at 0.1 vol / vol%

[0299] 0.5 mL of the composite obtained in Example 8 (corresponding to 0.4824 grams and containing 0.065 grams of adduct, of which 0.05 grams was graphite and 0.015 grams oleyl pyrrole, the remainder being Etro 4 oil) was added to 49.5 mL of Etro 4 oil. Everything was mixed with a magnetic stirrer for 2 minutes.

[0300] The mixture was then tested for diluted composite stability by applying METHOD 2, the results of which are shown in Table 6.

[0301] Example 19: Preparation of a composite between Nanographite / oleyl pyrrole adduct and Etro 4 oil, diluted in 0.05 vol / vol% oil

[0302] Following the process described in Example 18, 0.25 mL of the composite obtained in Example 8 was added to 49.75 mL of Etro 4 oil. Everything was mixed for 2 minutes.

[0303] The mixture was then tested for diluted composite stability by applying Method 2, the results of which are shown in Table 6.

[0304] Example 20: Preparation of a composite with Etro 4 oil and Nanographite / oleyl pyrrole combination, diluted to 0.01 vol / vol%

[0305] Following the process described in Example 18, 0.05 mL of the composite prepared in Example 8 was added to 49.75 mL of Etro 4 oil. Everything was mixed for 2 minutes.

[0306] The mixture was then tested for diluted composite stability by applying Method 2, the results of which are shown in Table 6.

[0307] Example 21: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination and surfactant SV261, diluted to 0.1 vol / vol%

[0308] Following the process described in Example 18, 0.5 mL of the composite obtained in Example 9 (corresponding to 0.4824 g and containing 0.05 g of graphite and 0.008 g of oleyl pyrrole) was added to 49.5 mL of Etro 4 oil. The mixture was mixed for 2 minutes.

[0309] The mixture was then tested for diluted composite stability by applying Method 2, the results of which are shown in Table 6.

[0310] Example 22: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination and SV261 surfactant diluted to 0.05 vol / vol%

[0311] Following the process described in Example 18, 0.25 mL of the composite obtained in Example 9 (corresponding to 0.2412 g and containing 0.025 g of graphite and 0.004 g of oleyl pyrrole) was added to 49.75 mL of Etro 4 oil. The mixture was mixed for 2 minutes.

[0312] The mixture was then tested for diluted composite stability by applying Method 2, the results of which are shown in Table 6.

[0313] Example 23: Preparation of a composite with Etro 4 oil, Nanographite / oleyl pyrrole combination and surfactant SV261, diluted to 0.01 vol / vol%

[0314] Following the process described in Example 18, 0.05 mL of the composite obtained in Example 9 was added to 49.75 mL of Etro 4 oil. The mixture was mixed for 2 minutes.

[0315] The mixture was then tested for diluted composite stability by applying Method 2, the results of which are shown in Table 6.

[0316] Example 23a (comparative) : Preparation of a composite with Etro 4 oil and Nanographite, diluted to 0.1 vol / vol%

[0317] Following the process described in Example 18, 0.5 mL of the composite obtained in Comparative Example 7, corresponding to 0.4674g (and containing 0.05g of graphite) was added to 49.5 mL of Etro 4 oil. The mixture was mixed for 2 minutes.

[0318] The mixture was then tested for diluted composite stability by applying Method 2, the results of which are shown in Table 6.

[0319] Table 6: stability (Method 2) of lubricants of Examples 18- 23a

[0320] EXAMPLES 24-26: Preparation of paraffinic wax composites comprising an adduct / combination of nanographite with a pyrrole compound and stability test (METHOD 3)

[0321] Example 24 (comparative) : Preparation of a Paraffinic Wax and Nanographite Composite

[0322] 50 g of paraffinic wax was placed in a 100 mL graduated cylinder and heated to 150°C. Once completely melted, 5 g of HSAG nano 24 nanographite was added.

[0323] It is mixed, under magnetic stirring, for 10 minutes at 150°C. It is then left under static conditions at 150°C for 6 hours and brought to room temperature (METHOD 3) , observing what is reported in Figure 1. The composition is provided in Table 7, while the results of the stability test (METHOD 3) are provided in Table 8 based on what is observed in Figure 1. Example 25: Preparation of a composite of Paraffin wax and combination of Nanographite and Oleyl Pyrrole added individually to the lipophilic matrix

[0324] Comparative Example 24 was repeated, except that after mixing for 10 minutes, 1.4 g of Oleyl pyrrole (OP) prepared in Example 1 was added to the wax + nanographite mixture at T=150°C under mixing.

[0325] Table 7 shows the composition while the stability results evaluated by applying METHOD 3 are shown in Table 8 based on what is observed in Figure 2.

[0326] Example 26: Preparation of a composite of Paraffinic Wax and Nanographite / Oleyl Pyrrole Adduct and stability test

[0327] The process of Example 24 was repeated, with the exception that 6.4g of Nanographite / Oleyl Pyrrole Adduct (4.9g nanographite + 1.5g oleyl pyrrole) prepared in Example 4 was added to the wax in place of the nanographite .

[0328] Table 7 shows the composition while the stability results evaluated by applying METHOD 3 are shown in Table 8 based on what is observed in Figure 3.

[0329] Table 7

[0330] Table 8

[0331] It can be seen from the data in Table 8 that the use o f the pyrrole compound results in greater stability of the composite with respect to that of the composite containing only nanographite .

[0332] EXAMPLES 27-29 : Preparation of EPR elastomer-based composites comprising nanographite and pyrrole compound, with rheological characterisation (METHOD 4 ) and diffractometry (METHOD 5)

[0333] The composites were prepared using a Brabender® type internal mixer with a 50 mL mixing chamber .

[0334] The nanographite was added to the di f ferent samples at 35 phr (per hundred rubber ) : the unit "phr" used here is to be regarded as equivalent to the unit "phm" (per hundred matrix ) used in the other examples for lipophilic matrixes other than rubber .

[0335] Example 27 ( comparative ) : Preparation of an EPR composite with Nanographite

[0336] 32.74 g EPR granules were introduced into the mixer at 80°C and masticated for 2 minutes, with the rotors rotating at 60 rpm.

[0337] 11.46 g of HSAG nano 24 nanographite was then added, and mixing was carried out for 3 minutes at 80°C. Table 9 shows the composition.

[0338] The product consisting of EPR-based composite material with Nanographite was then subjected to rheological characterisation by applying METHOD 4 in order to measure the elastic shear modulus G' as a function of certain strain amplitudes.

[0339] The curves describing the dependence of the elastic modulus G' on the strain amplitude are shown in Figure 4. The values of G' at 0.2%, 20% and 40% strain amplitude and the value of AG' (G'0.2 - G'40) are shown in Table 10.

[0340] The product consisting of EPR-based composite material with Nanographite was also subjected to X-ray diffractometry using METHOD 5, the results of which are shown in Figure 6.

[0341] A sample of EPR was also subjected to X-ray diffractometry according to METHOD 5, the results of which are shown in Figure 5.

[0342] Example 28: Preparation of an EPR composite with a combination of Nanographite and Oleyl Pyrrole (OP) added individually to the lipophilic matrix

[0343] 30.85 g EPR was introduced into the mixer at 80°C and masticated for 2 minutes, with the rotors rotating at 60 rpm.

[0344] Then 10.80 g of nanographite was added, and 2.47 g of Oleyl Pyrrole from Example 1 and mixing (80°C, 60 rpm) was carried out for 3 minutes. Table 9 shows the composition.

[0345] The product consisting of EPR-based composite material with individually dispersed Nanographite and Oleyl Pyrrole was then subjected to rheological characterisation by applying method 4 in order to measure the elastic shear modulus G' as a function of certain strain amplitudes (0.2%, 20% and 40%) .

[0346] The curves describing the dependence of the elastic modulus G' on the strain amplitude are shown in Figure 4. The values of G' at 0.2%, 20% and 40% strain amplitude and the value of AG' (G'0.2 - G'40) are shown in Table 10.

[0347] The product consisting of EPR-based composite material with Nanographite and Oleyl Pyrrole was also subjected to X-ray diffractometry using METHOD 5, the results of which are shown in Figure 7.

[0348] A sample of EPM was also subjected to X-ray diffractometry according to Method 5, the results of which are shown in Figure 5.

[0349] Example 29: Preparation of an EPR composite with Nanographite / Oleyl Pyrrole adduct

[0350] 31.70 g EPR was introduced into the mixer at 80°C and masticated for 2 minutes, with the rotors rotating at 60 rpm.

[0351] Then 13.63g of the nanographite / oleyl pyrrole adduct prepared in Example 4 (containing 10g of HSAG nano graphite 24 and 3.63g of oleyl pyrrole) was added, and mixing was carried out for a further 3 minutes at 60 rpm and 80°C. Table 9 shows the composition.

[0352] The product consisting of EPR-based composite material with Nanographite / Oleyl pyrrole adduct was then subjected to rheological characterisation by applying method 4 in order to measure the elastic shear modulus G' as a function of certain strain amplitudes (0.2%, 20% and 40%) .

[0353] The curves describing the dependence of the elastic modulus G' on the strain amplitude are shown in Figure 4. The values of G' at 0.2%, 20% and 40% strain amplitude and the value of AG' (G'0.2 - G'40) are shown in Table 10.

[0354] The product consisting of EPR-based composite material with Nanographite / Oleyl Pyrrole adduct was also subjected to X-ray diffractometry applying Method 5, the results of which are shown in Figure 8.

[0355] A sample of EPM alone was also subjected to X-ray diffractometry according to Method 5, the results of which are shown in Figure 5. Table 9

[0356] Table 10 : G' values of composite materials

[0357] The curves in Figure 4 and the data in Table 10 can be interpreted as follows .

[0358] The polyolefin material without nanographite shows that for strains up to 40% , there is an area of linear viscoelasticity and that in this area of linear viscoelasticity, the elastic shear modulus G' i s independent of the strain amplitude , as expected . The decrease of the modulus G' corresponding to high strain above 40% is only due to the fact that the detection of the modulus G' occurs in a non-linear viscoelasticity regime for the material .

[0359] The highest values of modulus G' and also the highest values of AG' (which represents the decrease in modulus G' as the strain amplitude increases ) among the materials tested are observed for the composite containing only nanographite , in the absence of pyrrole compound (EPM+HSAG 35phr ) .

[0360] These higher values indicate that a nanofiller-based lattice (nanographite ) is formed in the EPM+HSAG 35phr composite compared to EPM as such, and that this lattice formed by the HSAG allotrope is present in greater quantities in the EPM+HSAG 35phr composite than in other elastomeric materials .

[0361] The addition of the pyrrole compound, either as a single component during mixing (Example 28 ) or as a component of a nanographite / OP adduct prepared prior to its addition into the mixer (Example 29 ) , leads to the reduction of the elastic shear modulus G' and AG' with respect to the values of the modulus G' and AG' of the EPM+HSAG 35phr composite containing only nanographite .

[0362] These results indicate that a filler network, i . e . nanographite , is formed in smaller quantities in the composite with nanographite+pyrrole compound than in the composite with nanographite in the absence of the pyrrole compound .

[0363] Thus , the pyrrole compound promotes the distribution and dispersion of nanographite in the composite material as it causes a decrease in the nanographite lattice . The dif f ractograms shown in Figures 5 to 8 can be interpreted as follows.

[0364] The RX profile of EPM in Figure 5 shows no reflections at 2THETA= 26.7, which are typical of nanographite crystallinity.

[0365] The RX profile of EPM + nanographite in Figure 6 shows the typical reflection (002) at 2THETA=26.7 of nanographite, in the two orthogonal directions.

[0366] The RX profile of EPM + nanographite + OP in Figure 7 shows the typical reflection (002) at 2THETA=26.7 of the nanographite, in the two orthogonal directions. The reflection at 2THETA=26.7 appears less intense, however, when compared to the EPM +nanography band in Fig. 6.

[0367] The RX profile of EPM + nanographite / OP adduct in Figure 8 shows the typical reflection (002) at 2THETA=26.7 of the nanographite. The reflection appears even less intense when compared to the EPM +nanographite band in Fig. 6.

[0368] It should also be noted that in Fig. 8, the two spectra in the two directions are different from each other, which is an indication that the nanographite was exfoliated during the mixing process with the pyrrole compound (i) and in that form was incorporated into the EPM.

[0369] The results indicate that the pyrrole compound promotes the dispersion of the nanographite in the composite material: since the nanographite is composed of stacked layers and this stacking is detected in the X-ray dif f ractogram at 2THETA=26.7, the lower the reflection at 2THETA=26.7 the lower the stacking.

[0370] It is a reasonable interpretation / explanation of the aforementioned attenuation of the reflection that the nanographite + pyrrole combination / adduct has promoted the reduction of stacking and thus has promoted the separation of the nanographite into its layers, which are then dispersed in the matrix.

[0371] Moreover, the aforementioned attenuation is also an indication that nanographite modified with the pyrrole compound is less aggregated in the lipophilic matrix than unmodified nanographite.

[0372] EXAMPLES 30-32: Preparation of SBS elastomer-based composites (and Etro 4 oil) comprising nanographite and a pyrrole compound

[0373] EXAMPLE 30 (comparative) : Preparation of a composite in SBS (+ Etro 4 oil) with Nanographite

[0374] 6.48 g of SBS, 15.54 g of Etro 4 oil and 5.44 g of nanographite (24.7 phm of nanographite compared to SBS+oil) were placed in a speed mixer container with a capacity of 200 mL .

[0375] Etro 4 oil was used to enable an SBS-based composite to be prepared with a speed mixer, decreasing its viscosity so that it could be mixed. The mixture was placed in a

[0376] Hauschild DAC 150.1 FVZ speed mixer at 3000 rpm for 3 minutes. Table 11 shows the composition.

[0377] The product consisting of SBS-based composite material with Nanographite was also subjected to X-ray diffractometry using Method 5, the results of which are shown in Figure 10.

[0378] A sample of SBS + Etro 4 oil prepared by mixing 6.48 g SBS and 15.54 g Etro 4 oil in a 200 mL speed mixer container was also subjected to X-ray diffractometry according to Method 5. The results of METHOD 5 are shown in Figure 9.

[0379] EXAMPLE 31 : Preparation of a composite in SBS + Etro 4 oil with Nanographite and Oleyl pyrrole added individually to the lipophilic matrix

[0380] Following the process in Example 30, 6.20 g of SBS, 14.85 g of Etro 4 oil, 4 g of Nanographite and 1.20 g of Oleyl Pyrrole prepared in Example 1 were placed in a speed mixer container. This was placed in the speed mixer used in example 30 at 3000 rpm for 3 minutes, observing a temperature rise that has heated the mixture. Table 11 shows the composition.

[0381] The product consisting of SBS-based composite material containing Nanographite and Oleyl Pyrrole was also subjected to X-ray diffractometry using Method 5, the results of which are shown in Figure 11.

[0382] EXAMPLE 32 : Preparation of a composite in SBS + Etro 4 oil with Nanographite / Oleyl pyrrole adduct

[0383] Following the process in Example 30, 6.32g SBS, 15.17g Etro 4 oil and 6.52g Nanographite / Oleyl pyrrole adduct prepared in Example 4 (containing 5g nanographite and 1.52g oleyl pyrrole) were placed in a speed mixer container. The mixture was placed in the speed mixer used in Example 30 at 3000 rpm for 3 minutes. Table 11 shows the composition.

[0384] The product consisting of SBS-based composite material with Nanographite and Oleyl Pyrrole adduct was also subjected to X-ray diffractometry applying Method 5, the results of which are shown in Figure 12.

[0385] Table 11

[0386] The dif f ractograms shown in Figures 9 to 12 can be interpreted as follows.

[0387] The RX profile of SBS in Fig. 9 shows no reflections at 2THETA= 26.7, which are typical of nanographite crystallinity.

[0388] The RX profile of SBS + nanographite in Fig. 10 shows the typical reflection (002) at 2THETA=26.7 of nanographite, in the two orthogonal directions.

[0389] The RX profile of SBS + nanographite + OP in Fig. 11 shows the typical reflection (002) at 2THETA=26.7 of nanographite, in the two orthogonal directions. The reflection at 2THETA=26.7 appears less intense, however, when compared to the SBS + nanographite band in Fig. 10, as well as being less sharp.

[0390] The RX profile of SBS + nanographite / OP adduct in Fig. 12 shows the typical reflection (002) at 2THETA=26.7 of nanographite. The reflection appears even less intense, compared to the SBS + nanographite band in Fig. 10 and even less sharp.

[0391] These results indicate that the pyrrole compound promotes the dispersion of nanographite in the composite material. Since the nanographite is composed of stacked layers and this stacking is detected in the X-ray dif f ractogram at 2THETA=26.7, the lower the reflection at 2THETA=26.7 the lower the stacking.

[0392] A reasonable interpretation / explanation of the aforementioned attenuation of the reflection at 2THETA=26.7

[0393] IS that the nanographite pyrrole combination, particularly in adduct form, has promoted the reduction of stacking and thus has promoted the separation o f the nanographite into its layers , which are then dispersed in the matrix . Moreover, the above-mentioned attenuation is also an indication that re-aggregation of the carbonaceous material in the lipophilic matrix did not occur .

Claims

CLAIMS1 . Process for preparing composite materials having a lipophilic matrix and comprising dispersions of sp2carbon allotropes in the lipophilic matrix of said composite material , said process comprising the steps of(A) mixing, optionally in the presence of one or more solvents , a sp2carbon allotrope , in particular sp2carbon allotropes having at least one dimension smaller than 100 nm, with a compound containing a pyrrole ring of formula ( 1 )wherein :Ri and R2 are , independently one from the other, hydrogen or an alkyl group containing a number o f carbon atoms ranging from 1 to 20 , preferably from 1 to 10 , more preferably from 1 to 5 , even more preferably from 1 to 2 ,Ri, R2 being preferably an alkyl group as defined above ;R3 is an unsubstituted linear or branched aliphatic group, with or without unsaturation,and not containing functional groups such as for example OH, 0=0, said R3 containing a number of carbon atoms ranging from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, even more preferably from 6 to 20; or- R3is a polymeric chain, preferably deriving from a polyamine, e.g. triethylenetetramine (TETA) , Diethylenetriamine (DETA) , and from polyisobutylene (RIB) and maleimide; or R3is a polymer chain composed of a polyetheramine containing a poly (oxyalkylene) chain, for example a jeffamine (5, 8-Dimethyl-4 , 7, 10-trioxatridecane-2 , 12- diamine) , said compound (i) being optionally obtained in situ in said step (A) by reaction of a 1,4-diketone with a primary amine R-NH2 wherein R=R3of the compound of formula (i) ;(A' ) optionally removing one or more of said solvents, when present, to obtain a solid or semi-solid mixture ;(B) heating, preferably under stirring and / or mixing, the mixture comprising the sp2carbon allotrope and the pyrrole compound of formula (i) ;(C) mixing, preferably under heating, the mixture obtained in step (B) with a compound of a lipophilic naturewhich constitutes the lipophilic matrix of a composite material to obtain a composite, preferably in the form of a paste, having a predetermined concentration of said sp2carbon allotrope in said lipophilic matrix of the composite material ; and optionally(D) diluting, preferably by mixing, the composite obtained in step (C) with a compound of a lipophilic nature, equal to or different from that used in step (C) , to obtain a composite having a total concentration of said sp2carbon allotrope lower than the predetermined one obtained in step (C) .

2. Process according to claim 1, wherein the compound of a lipophilic nature which constitutes the lipophilic matrix of the composite material has a molecular weight greater than 200g / mol, excluding isoprene rubbers, butadiene rubber and the like.

3. Process according to claim 1 or 2, wherein the sp2carbon allotrope is selected from graphene, nanographites consisting of a few graphene layers (from a few units to a few tens) , nano-graphites with a high surface area (HSAG) , preferably between 100 and 400 m2 / g, graphite, graphene, fullerene, carbon nanotubes or combinations thereof; preferably high surface area nano-graphites(HSAG) .

4. Process according to claim 1 or 2 or 3, wherein steps (A) , (B) , (C) can be carried out separately in sequence; or all three steps can be carried out simultaneously, adding the components (allotrope, pyrrole compound (i) , and lipophilic matrix) individually in any order; or the first two steps (A) and (B) can be carried out simultaneously to obtain an addition product between the sp2carbon allotrope and the pyrrole compound (i) , then following step (C) in which the product obtained from step (B) is mixed with the lipophilic matrix.

5. Process according to any of the preceding claims 1-4, wherein said step (A) is carried out by dispersing, under stirring or sonication, the allotrope and the compound (i) in a low-boiling solvent selected from apolar solvents, polar protic solvent or polar aprotic solvents.

6. Process according to any one of the preceding claims 1-4, wherein the steps (A) , (B) and (C) are carried out simultaneously, adding, optionally under heating, the allotrope and the pyrrole compound (i) individually to the lipophilic matrix (one step one pot) .

7. Process according to any one of the preceding claims, wherein before the step (A) a step (AO) is provided for preparation of the compound (i) by means of the PaalKnorr reaction between a 1,4-diketone of formulaand a primary amine R-NH2 wherein the R group is equal to the R3 group of the compound of formula (1) .

8. Process according to any one of the preceding claims, wherein step (B) takes place under heating at a temperature generally comprised between 80-100°C and 170°C, preferably comprised between 130°C and 170°C, more preferably comprised between 130 °C and 160°C, even more preferably around 150°C.

9. Process according to any one of the preceding claims, wherein step (C) is carried out under heating at a temperature at which the lipophilic matrix is in a liquid or molten state, preferably at a temperature of at least 80 -100°C.

10. Process according to any one of the preceding claims, wherein the predetermined concentration of the sp2carbon allotrope in the lipophilic matrix of the composite material obtained from step (C) is comprised in the range, which varies- from 0.5 to 50 phm,- preferably between 1 to 35 phm, where phm means per hundred parts of lipophilic matrix(per hundred matrix) , the lipophilic matrix possibly being base oil, wax, elastomer, grease or other type of lipophilic matrix or combinations thereof, preferably base oil, wax, lubricating grease or combinations thereof.

11. Process according to any one of the preceding claims, wherein the amount of pyrrole compound of formula (i) with respect to the amount of sp2carbon allotrope is in the range ranging from 3 phc to 50 phc (per hundred carbon, considering 100 phc the amount (by weight) of sp2carbon allotrope) .

12. Process according to any one of the preceding claims wherein the lipophilic compound (lipophilic matrix) is selected from- lubricating oils or base oils used in lubricating compositions, said oils having mineral or synthetic origin, or deriving from renewable raw materials, ; fat lubricants;- waxy compounds solid at room temperature, such as paraffinic waxes, animal waxes, vegetable waxes, preferably hydrocarbon compounds, saturated fatty acids, esters of saturated fatty acids having a number of carbon atoms equal to or greater than 12 to 32, e.g. acid esters myristic, palmitic, lauric, stearic, hexacosanoic and the like, the molecules of which have alkyl chains with a number of carbon atoms equal to orgreater than 12 to 32;- polymeric matrixes, for example elastomers (e.g. gaskets, rubbery materials) , in particular "EPR / EPM" (rubbers based on ethylene - propylene copolymers) and typical block copolymers called SBS(styrene / butadiene / styrene) ;- combinations thereof.

13. Process according to any one of the preceding claims, wherein the amount of pyrrole compound of formula (i) used with respect to the sp2carbon allotrope is in the range ranging from 3 phc (per hundred carbon) to 50 phc, where phc means "per hundred parts of carbon" considering 100 phc the amount (by weight) of the allotrope.

14. Metal free additives for conferring anti-friction and anti-wear properties to lubricating compositions in the form of oils or greases, said additives being in the form of a composite material comprising a sp2carbon allotrope, in particular sp2carbon allotropes having at least one dimension smaller than 100 nm, a pyrrole compound of formula (i) as defined in any one of the preceding claims a lipophilic matrix in the form of a base oil or lubricant as defined in claim 2 and / or 12, wherein the concentration of said allotrope in saidbase or lubricant oil is included in the range ranging from0.5 to 50 phm (per hundred matrix, considering 100 phm said base oil or lubricant) , said additives being preferably obtainable from step (C) of the process according to any one of the preceding claims .

15. Wax-based composite materials comprising a sp2carbon allotrope, in particular sp2carbon allotropes having at least one dimension smaller than 100 nm, a pyrrole compound of formula (i) as defined in any one of the preceding claims, a lipophilic material in the form of a waxy compound as defined in claim 2 and / or 12, wherein the concentration of said sp2carbon allotrope in said waxy compound ranges from 0.5 to 50 phm (per hundred matrix, considering 100 phm said wax compound) , said composite materials being preferably obtainable from step (C) of the process according to any one of the preceding claims.

16. Masterbatch additives for elastomers to impart mechanical strength to elastomeric materials such as gaskets, rubbery materials, coatings, said additives being in the form of a composite material comprising a sp2carbon allotrope, in particular sp2carbonallotropes having at least one dimension smaller than 100 nm, a pyrrole compound of formula (i) as defined in any one of the preceding claims a lipophilic matrix in the form of an elastomer, preferably selected from SBS and EPM, wherein the concentration of said sp2carbon allotrope in said lipophilic matrix is in the range ranging from 0.5 to 50 phm (per hundred matrix, considering 100 phm said elastomer) , said composite material being preferably obtainable from step (C) of the process according to any one of the preceding claims.

17. Additives according to any one of the preceding claims 14 , 16 and / or composite materials according to claim 15, wherein said sp2carbon allotrope is selected from graphene, nano-graphites consisting of a few graphene layers (from a few units to a few tens) , high surface area nano-graphites (HSAG) , preferably comprised between 100 and 400 m2 / g, graphite, graphene, fullerene, carbon nanotubes or combinations thereof; preferably high surface area nanographites (HSAG) .

18. Additives and / or composite materials according to any one of the preceding claims from 14 to 17 , wherein the amount of pyrrole compound of formula (i) used with respectto the sp2carbon allotrope is in the range ranging from 3 phc (per hundred carbon) to 50 phc, where phc means "per hundred parts of carbon" considering 100 phc the amount (by weight ) of the sp2carbon allotrope . 19 . Lubricating compositions in the form o f lubricating oils and / or greases comprising a base oil and at least one metal free additive to impart anti- friction and anti-wear properties , wherein said at least one additive is a composite material as defined in any one of claims 14 , 17 , 18 .

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