COMPOSITION CONTAINING BIS-UREAS FOR FORMING STABLE GELS

Abstract

The invention relates to a composition comprising classic bis-ureas and bis-ureas functionalised by macromolecular chains, said bis-ureas including complementary spacers of the aryl type, the mixture of said bis-ureas in a solvent leading to a stable physical gel. The invention also relates to a method for producing said composition and to the use of said composition as an organogelator, alone or in a cosmetic preparation, an ink, a fuel or a lubricant, especially of a motor vehicle.

Claims

1-10. (canceled)

11. Composition comprising a mixture of conventional bis-ureas and bis-ureas functionalised by macromolecular chains, wherein: the conventional bis-ureas are of general formula (I) ##STR00113## wherein X represents a phenyl group substituted by at least one alkyl chain comprising 1 to 4 carbon atoms and/or at least one halogen selected from Cl or Br; R.sub.1 and R.sub.2 each represent independently a linear or branched group, selected from alkyl, alkene, alkyne, aryl, arylalkyl, heteroaryl, heteroalkyl, heteroalkene or heteroalkyne; said linear or branched group optionally being substituted by a halogen, alkyl, alkene, alkyne, heteroalkyl, heteroalkene or heteroalkyne group; the bis-ureas functionalised by macromolecular chains are of general formula (II) ##STR00114## wherein Y represents a phenyl group substituted by at least one alkyl chain comprising 1 to 4 carbon atoms and/or at least one halogen selected from Cl or Br; at least one of R.sub.3 and R.sub.4 represents a macromolecular chain, and one of X and Y is optionally substituted by one or two groups each independently selected from an alkyl chain comprising 1 to 4 carbon atoms and/or a halogen selected from Cl or Br; and the other of X and Y is substituted by three or four groups, each independently selected from alkyl chains comprising 1 to 4 carbon atoms and the halogens selected from Cl or Br.

12. Composition according to claim 1, wherein at least one of R.sub.3 and R.sub.4 represents a macromolecular chain selected from the family comprising polyacrylates, polymethacrylates, polyolefins, polycarbonates, polyethers, polydienes, polyvinyl acetates, polycarbonates, polysiloxanes, polyesters, polynorbornenes, polycyclooctenes and polystyrenes; and the other one of R.sub.3 and R.sub.4 represents a linear or branched group, selected from alkyl, alkene, alkyne, aryl, arylalkyl, heteroaryl, heteroalkyl, heteroalkene or heteroalkyne; said linear or branched group optionally being substituted by a halogen, alkyl, alkene, alkyne, heteroalkyl, heteroalkene or heteroalkyne group, or a macromolecular chain.

13. Composition according to claim 1, wherein R.sub.3 and R.sub.4 are identical and each represent a macromolecular chain of polyisobutene or poly(butyl acrylate).

14. Composition according to claim 1, wherein the conventional bis-ureas of formula (I) are selected from ethylhexylureidotoluene (EHUT), ethylhexylureidotrimethylbenzene (EHUTMB) and ethylhexylureidoxylene (EHUX).

15. Composition according to claim 1, wherein the bis-ureas of formula (I) are EHUTMB molecules.

16. Composition according to claim 1, wherein the bis-ureas functionalised by macromolecular chains of formula (II) are selected from poly(isobutene)ureidotoluene (PIBUT), poly(isobutene)ureidotrimethylbenzene (PIBUTMB), poly(isobutene)ureidoxylene (PIBUX) and poly(butyl acrylate)ureidoxylene (PABUX).

17. Composition according to claim 1, wherein the functionalised bis-urea is selected from PIBUX and PABUX.

18. Composition comprising the mixture according to claim 1, and at least one solvent.

19. Composition comprising the mixture according to claim 1 and a solvent, wherein the solvent is selected from non-polar solvents having long alkyl chains or polar solvents.

20. Method for preparing a composition comprising the mixture according to claim 1 and at least one solvent, wherein the method comprises mixing conventional bis-ureas of formula (I) and functional bis-ureas of formula (II) with at least one solvent, under gentle stirring and optionally in the presence of heating.

21. Method according to claim 10, wherein the solvent is a non-polar solvent having long alkyl chains or an oil.

22. Method according to claim 10, wherein said oil comprises vegetable, animal, mineral or synthetic oils, liquid hydrocarbon combustibles, fuels, lubricants.

23. Method according to claim 10, wherein said oil is PA06 oil.

24. Method according to claim 10, wherein the solvent is a polar solvent.

25. Additive comprising the mixture according to claim 1, wherein said additive is present in a cosmetic composition, or an ink, in a fuel, or in a lubricant.

26. Organogelator comprising a composition comprising the mixture according to claim 1 and at least one solvent.

27. Organogelator comprising a composition comprising the mixture according to claim 1 and at least one solvent, wherein said organogelator is present in a cosmetic preparation, an ink, a fuel or a lubricant.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0215] FIG. 1 is a photograph showing solutions of EHUTMB (on the left), PIBUX (on the right) and an EHUTMB/PIBUX mixture (90% mol/10% mol) (at the middle) in solution in dodecane (4 g/l).

[0216] FIG. 2A is a photograph showing solutions of EHUTMB (on the right), PABUX (on the left) and equimolar EHUTMB/PABUX mixture (in the middle) in solution in ethyl acetate (50 g/l).

[0217] FIG. 2B is a photograph showing solutions of EHUTMB (on the right), PABUX (on the left) and equimolar EHUTMB/PABUX mixture (in the middle) in solution in THF (100 g/l).

[0218] FIG. 3 is a graph showing the change in relative viscosities for various solutions in toluene (40 g/l) comprising conventional bis-ureas having a trimethylbenzene spacer (EHUTMB), alone or in association with bis-ureas functionalised by macromolecular chains having either a xylene spacer (PIBUX) or a trimethylbenzene spacer (PIBUTMB).

[0219] FIG. 4 presents the infrared spectra of two PIBUX/EHUTMB mixtures (at the top, equimolar composition; at the bottom, PIBUX/EHUTMB composition 10% mol/90% mol in solution in toluene at 4 g/l, taken at various temperatures between 20° C. and 80° C.

[0220] FIG. 5 is a graph showing the change in the ratio of the absorption bands of the NH bond of the bis-ureas (3333 cm.sup.−1 and 3300 cm.sup.−1) as a function of the temperature of the mixture for an equimolar PIBUX/EHUTMB composition in toluene.

[0221] FIG. 6 presents the infrared spectra of two EHUTMH/PIBUX mixtures (% mol/% mol) 70/30 (6A) and 90/10 (6B) in dodecane at 4 g/l taken at various temperatures between 20° C. and 110° C.

[0222] FIG. 7 is a graph showing the change in the ratio of the absorption bands of the NH bond of the bis-ureas (3333 cm.sup.−1 and 3300 cm.sup.−1) as a function of the temperature of the mixture for EHUTMB/PIBUX mixtures (% mol/% mol) 30/70 (7A); 40/60 (7B); 60/40 (7C); 70/30 (7D) and 90/10 (7E) in dodecane.

[0223] FIG. 8 is a graph showing the change in the relative viscosities of EHUTMB/PIBUX solutions in toluene (2 g/l) at various temperatures.

[0224] FIG. 9 presents a change in the moduli of elasticity G′ and G″ of an EHUTMB/PIBUX mixture (90% mol/10% mol) in dodecane (4 g/l).

[0225] FIG. 10 is a photograph showing solutions of EHUTMB (on the left), of PDMSUT (on the right) and of an equimolar EHUTMB/PDMSUT mixture (in the middle) in solution in decamethylcyclopentasiloxane (25 g/l).

EXAMPLES

[0226] The present invention will be understood better from a reading of the following examples, which illustrate the invention non-limitatively.

Example 1: Obtaining Gels from an Equimolar Mixture of Conventional and Functionalised Bis-Ureas in the Presence of a Non-Polar Solvent—Influence of the Spacer

[0227] These experiments show that, under certain conditions, it is possible to form stable gels in solvents wherein conventional bis-ureas do not make it possible to obtain gels that are stable over time or to obtain gels having a gel/liquid transition temperature higher than ambient temperature.

[0228] Various bis-urea solutions were studied in toluene (5 mM):

[0229] solutions of conventional bis-ureas selected from EHUT, EHUTMB or EHUX;

[0230] solutions of bis-urea functionalised by poly(isobutene) chains selected from PIBUT, PIBUTMB or PIBUX;

[0231] equimolar mixtures of solutions of conventional and functionalised bis-ureas.

1.1. Macroscopic Assessment of the Solutions

[0232] Table 1 presents the results obtained for these various solutions.

TABLE-US-00002 TABLE 1 Rheological behaviour of various bis-urea solutions Absence of Solution conventional comprising . . . bis-ureas EHUT EHUTMB EHUX Absence of — — Liquid — functionalised bis-ureas PIBUT Liquid Liquid Gel Gel PIBUTMB Liquid Gel Liquid Gel PIBUX Liquid Gel Gel —

[0233] Surprisingly, the applicant found that:

[0234] alone, the conventional EHUT, EHUTMB and EHUX bis-ureas do not make it possible to form gels in toluene;

[0235] alone, the bis-ureas functionalised by poly(isobutene) chains (PIBUT, PIBUTMB and PIBUX) do not make it possible to form gels. Without wishing to be bound by any theory, the applicant thinks that the functionalised bis-ureas could not form gels because of the steric hindrance of the macromolecular chains, which prevents tubular autoassembly of functionalised bis-ureas;

[0236] equimolar mixing of conventional and functionalised bis-ureas comprising identical spacers, that is to say EHUT/PIBUT mixtures (with a toluene spacer) and EHUTMB/PIBUTMB (with a trimethylbenzene spacer) does not make it possible to form gels;

[0237] equimolar mixing of conventional and functionalised bis-ureas comprising different spacers, that is to say the mixtures EHUT/PIBUX, EHUT/PIBUTMB, EHUTMB/PIBUT, EHUTMB/PIBUX, EHUX/PIBUT and EHUX/PIBUTMB, does not make it possible to form stable gels.

[0238] Comparable results were obtained in dodecane.

1.2. Example of the EHUTMB/PIBUX Mixture in Dodecane

[0239] FIG. 1 presents a photograph showing a solution of EHUTMB (on the left), of PIBUX (on the right) and of the EHUTMB/PIBUX mixture (90% mol/10% mol) (in the middle) in dodecane (4 g/l) at ambient temperature.

[0240] FIG. 1 shows that the conventional bis-urea EHUTMB is not soluble in dodecane (white precipitate) unlike the functionalised bis-urea PIBUX, which provides a homogeneous solution.

[0241] The photograph also shows that the EHUTMB/PIBUX mixture (90% mol/10% mol) of these bis-ureas comprising complementary spacers (a trimethylbenzene spacer for EHUTMB and a xylene spacer for PIBUX) makes it possible to obtain 1) good solubilisation of the EHUTMB bis-ureas in dodecane (no precipitate), and 2) the formation of a gel.

1.3. Conclusions

[0242] The mixing at ambient temperature of conventional bis-ureas and bis-ureas functionalised by polyisobutene chains having complementary spacers makes it possible 1) to improve the solubilisation of conventional bis-ureas and 2) to provide gels in a solvent wherein, alone, conventional bis-ureas are not soluble or do not form a gel (here in dodecane).

Example 2: Obtaining Gels from an Equimolar Mixture of Conventional and Functionalised Bis-Ureas in the Presence of a Polar Solvent—Influence of the Spacer

[0243] The formation of a gel is obtained by the tubular autoassembly of bis-ureas in solution by means of intermolecular hydrogen bonds. However, depending on the polarity of the solvent, there may exist a competition between the formation of hydrogen bonds between the bis-ureas and the formation of hydrogen bonds between the bis-ureas and the solvent.

[0244] This study aims therefore to assess the effect of the complementary spacers of the mixture of bis-ureas on the formation of gel in polar solvents, unfavourable to the association of bis-ureas in solution.

[0245] Since polyisobutene chains are insoluble in polar solvents, macromolecular chains of poly(butyl acrylate) were used to functionalise the bis-urea having a xylyl spacer. The bis-urea obtained is the poly(butyl acrylate) ureidoxylene bis-urea (PABUX). The conventional EHUTMB bis-urea has a trimethylbenzene spacer.

2.1. In Ethyl Acetate

[0246] The conventional EHUTMB bis-urea (FIG. 2A, on the right) is not soluble in ethyl acetate at a concentration of 50 g/l, unlike the functionalised bis-urea PABUX for the same concentration, which leads to a clear liquid (FIG. 2A, on the left).

[0247] However, it is found that the equimolar EHUTMB/PABUX mixture, at a concentration of 50 g/l, provides a translucent gel that does not flow, even when the sample is turned over (FIG. 2A, in the middle).

2.2. In THF

[0248] The bis-ureas EHUTMB (FIG. 2B, on the right) and PABUX (FIG. 2B, on the left) are each soluble in THF at a concentration of 100 g/l. However, these bis-urea solutions do not form a gel at ambient temperature; these solutions are liquid.

[0249] The equimolar mixture EHUTMB/PABUX, in THF at a concentration of 100 g/l, provided a gel that does not flow, even when the sample is turned over (FIG. 2B, in the middle).

2.3. Conclusion

[0250] The functionalised bis-urea PABUX promoted the solubilisation of the conventional bis-urea EHUTMB in solvents unfavourable to the formation of gel by hydrogen bonds.

[0251] This solution can be compared with that observed for the PIBUX/EHUTMB mixture in dodecane (and when the macromolecular chains are polyisobutene chains) where the hydrogen bonds between bis-ureas were stronger.

[0252] It is therefore demonstrated here that the invention covers a wide variety of possibilities, where it is possible to select the nature of the appropriate macromolecular chain for solubilising and stabilising the assemblies of bis-urea in the selected solvent: here poly(butyl acrylate) chains for polar solvents. These assemblies could be solubilised at ambient temperature, which is a certain advantage, and allowed the formation of gels.

[0253] It was also demonstrated that the competition between the formation of hydrogen bonds between the solvents and bis-ureas on the one hand and the autoassociation of bis-ureas on the other hand may be counterbalanced by the preferential interaction between complementary spacers, here between xylene and trimethylbenzene spacers.

Example 3: Effect of the Composition of EHUTMB/PIBUX Mixtures on the Formation of Gel in Dodecane

[0254] The conventional bis-urea EHUTMB is not soluble in non-polar solvents having long alkyl chains such as dodecane.

[0255] The functionalised bis-urea PIBUX is soluble in dodecane.

[0256] PIBUX/EHUTMB solutions at a concentration of 4 g/l in dodecane were prepared and a macroscopic observation of the resulting compositions was carried out.

[0257] Table 2 shows the results obtained for the various mixtures produced according to the molar quantity of functionalised bis-ureas (PIBUX) compared with the total molar quantity of bis-ureas introduced into the mixture.

TABLE-US-00003 TABLE 2 Macroscopic appearance of solutions comprising the bis-ureas PIBUX and EHUTMB for various compositions PIBUX/EHUTMB mixture (% mol of PIBUX in the mixture) <30 30-70 >70 Precipitate Gel Liquid

[0258] The results show that PIBUX improves the solubilisation of EHUTMB in dodecane; this is because, when the composition comprises mainly functionalised PIBUX bis-ureas (>70% mol PIBUX in the mixture), a homogeneous liquid solution is obtained: conventional and functionalised bis-ureas are solubilised in the medium.

[0259] Moreover, these results show that intermediate compositions of an EHUTMB/PIBUX mixture (that is to say where the quantity of EHUTMB and PIBUX is between 30% and 70% mol with respect to the total quantity of bis-ureas in the medium) make it possible to obtain elastic gels at ambient temperature without heating.

[0260] When the composition comprises mainly conventional EHUTMB bis-ureas (<30% mol PIBUX), the composition does not make it possible to obtain stable homogeneous gels.

[0261] In conclusion, these results show that stable gels are obtained for compositions comprising 30% to 70% mol functionalised PIBUX bis-ureas with respect to the total molar quantity of bis-ureas in the medium.

Example 4. Revealing by Viscometry the Effect of Complementary Spacers for an EHUTMB/PIBUX Mixture in Toluene

[0262] This experiment aims to confirm, by viscometry, the effect of complementary spacers on the formation of gel in toluene.

[0263] In order to evaluate the influence of spacers on the viscosity of the mixture, the experiments were carried out in a solvent wherein conventional bis-ureas and functionalised bis-ureas are each individually soluble.

[0264] Several solutions of bis-ureas were produced in toluene, at a total concentration by mass of bis-ureas of 40 g/l and at a concentration by mass of between 13% and 16% bis-ureas with respect to the total quantity of solid:

[0265] solutions comprising conventional bis-ureas having a trimethylbenzene spacer (EHUTMB), alone;

[0266] solutions comprising a mixture of conventional bis-ureas having a trimethylbenzene (EHUTMB) spacer and functionalised bis-ureas having a trimethylbenzene (PIBUTMB) spacer;

[0267] solutions comprising a mixture of conventional bis-ureas having a trimethylbenzene spacer (EHUTMB) and functionalised bis-ureas having a xylene spacer (PIBUX).

[0268] FIG. 3 presents the change in relative viscosities for these various solutions according to the molar concentration of conventional EHUTMB bis-ureas in the medium.

[0269] The results show that:

[0270] solutions comprising only conventional bis-ureas having a trimethylbenzene (EHUTMB) spacer are not very viscous, the solutions remain liquid;

[0271] the mixture of conventional EHUTMB bis-ureas and functionalised PIBTMB bis-ureas, having identical spacers (trimethylbenzene), leads to solutions having a viscosity comparable to that of solutions comprising conventional bis-ureas EHUTMB alone;

[0272] the mixture of conventional EHUTMB bis-ureas and functionalised PIBUX bis-ureas, having different and complementary spacers (respectively trimethylbenzene and xylene) leads to solutions having a viscosity greater than that of solutions comprising conventional EHUTMB bis-ureas alone.

[0273] In conclusion, these results confirm the importance of the pair of spacers selected in the mixing of conventional bis-ureas and functionalised bis-ureas, for formulating a gel. In particular, it was shown that the mixing of functionalised bis-ureas having a xylene spacer (PIBUX) with conventional bis-ureas having a trimethylbenzene spacer (EHUTMB) leads to increases in relative viscosity; representing a good autoassociation of these compounds in the mixture.

Example 5: Revealing by FTIR Spectrometry the Effect of Complementary Spacers for EHUTMB/PIBUX Mixtures—Stability of the Gels Under Temperature

[0274] This experiment aims to evaluate, by FTIR spectroscopy, the stability under temperature of various compositions comprising the mixture of conventional bis-ureas having a trimethylbenzene spacer (EHUTMB) and functionalised bis-ureas having a xylene spacer (PIBUX).

[0275] FTIR analysis makes it possible to observe the absorption bands of the NHs of the urea functions. The NH bond resonates at a different frequency depending on whether it is bonded (<3400 cm.sup.−1) or not (>3400 cm.sup.−1) by hydrogen bonds to another urea function. Moreover, the ratio of the absorbances at 3330 and 3300 cm.sup.−1 is characteristic of the structure of their assembly; this ratio is around 1.1 for the filamentary structure and around 1.3 for the tubular structure.

5.1. In Toluene

[0276] An analysis was carried out at various temperatures on an EHUTMB/PIBUX mixture in solution in toluene at a total concentration by mass of bis-ureas of 4 g/l, for EHUTMB/PIBUX compositions (% mol/% mol): 50/50 and 90/10.

[0277] The results presented in FIG. 4 show that, for an EHUTMB/PIBUX mixture (50% mol/50% mol), the NH absorption bands change form when the temperature of the mixture is above or equal to about 70° C. The gel/liquid transition temperature of the EHUTMB/PIBUX mixture (50% mol/50% mol) in toluene is therefore about 70° C. The gel obtained by EHUTMB/PIBUX (50% mol/50% mol) in toluene therefore remains stable when it is heated at temperatures not exceeding 70° C.

[0278] For an EHUTMB/PIBUX mixture (90% mol/10% mol) the NH absorption bands change form when the temperature of the mixture is greater than or equal to about 50° C. The gel/liquid transition temperature of the EHUTMB/PIBUX mixture 90% mol/10% mol) in toluene is therefore about 50° C. The gel obtained by EHUTMB/PIBUX (90% mol/10% mol) in toluene therefore remains stable when it is heated to temperatures not exceeding 50° C.

[0279] FIG. 5 presents the change in the ratio of the absorbances at 3330 and 3300 cm.sup.−1 as a function of the temperature of an EHUTMB/PIBUX mixture (90% mol/10% mol). This representation confirms that the gel/liquid transition temperature for this mixture is about 50° C.

5.2. In Dodecane

[0280] An analysis was carried out at various temperatures on an EHUTMB/PIBUX mixture in solution in dodecane at a total concentration by mass of bis-ureas of 4 g/l, for EHUTMB/PIBUX compositions (% mol/% mol): 90/10; 30/70; 40/60; 60/40 and 70/30.

[0281] The results are presented in FIGS. 6 and 7.

[0282] Comparably with the experiments carried out in toluene, these results show that the NH absorption bands change form when the temperature of the mixture increases (examples for the EHUTMB/PIBUX (% mol/% mol) 90/10 and 70/30 compositions, FIGS. 6A and 6B).

[0283] FIGS. 7A-7E show that the gel/liquid transition in dodecane is above 50° C. In particular, the compositions comprising mixtures of 30% to 70% mol conventional bis-ureas and functionalised bis-ureas provide gels that are stable under temperature up to about 100° C.

5.3. Conclusions

[0284] In conclusion, these results show that it is possible, by FTIR spectroscopy 1) to evaluate the transition temperature from a gel state to a liquid state, and 2) to evaluate the stability under temperature of mixtures of bis-ureas. These results also show that mixing conventional bis-ureas and functionalised bis-ureas having complementary spacers according to the invention (here EHUTMB/PIBUX) makes it possible to obtain gels having improved stabilities under temperature (the mixtures remain stable at temperatures very much greater than ambient temperature).

Example 6: Influence of Temperature on the Relative Viscosity of EHUTMB/PIBUX Mixtures

[0285] The mixing of conventional bis-ureas having a trimethylbenzene spacer (EHUTMB) and functionalised bis-ureas having a xylene spacer (PIBUX) was studied in toluene, a solvent wherein these two bis-ureas are soluble, at a total concentration of bis-ureas in toluene of 2 g/l.

[0286] The aim is to evaluate the temperature range over which the EHUTMB/PIBUX provides a stable gel. For this purpose, the relative viscosity of various EHUTMB/PIBUX compositions was measured at 20° C., 40° C., 60° C. and 80° C.

[0287] The results (FIG. 8) show that the EHUTMB/PIBUX composition (50% mol/50% mol) has a very high relative viscosity (>18) when this mixture is heated to a temperature below 80° C.; on the other hand, the viscosity is minimal when the mixture is heated to 80° C.

[0288] In addition, these results show that:

[0289] a solution comprising only EHUTMB is of very low viscosity whatever the temperature (20°, 40°, 60° or 80° C.);

[0290] a solution comprising only PIBUX is moderately viscous at 20° C. and becomes less and less viscous when the temperature is increased up to 80° C.;

[0291] a solution comprising a PIBUX/EHUTMB mixture has high viscosities at temperatures ranging up to 60° C., in particular an equimolar PIBUX/EHUTMB mixture is stable up to a temperature of 67° C.

[0292] Consequently these results show that an equimolar mixture of conventional bis-ureas having a trimethylbenzene spacer and functionalised bis-ureas having a xylene spacer makes it possible to obtain a gel that is stable up to a temperature of 67° C.

Example 7: Rheological Analysis of EHUTMB/PIBUX Mixtures in Dodecane

[0293] A mixture of conventional EHUTMB bis-ureas and functionalised PIBUX bis-ureas at an EHUTMB/PIBUX molar composition of 90/10 was studied in rheology.

[0294] The EHUTMB/PIBUX mixture (90/10) is in solution in dodecane at a total concentration by mass of bis-ureas of 4 g/l.

[0295] Rheological analysis, and in particular a study of the modulus of elasticity G′ and of the viscosity modulus G″ of a sample, makes it possible to evaluate the rheological behaviour of a material. This is because a material is considered to be an elastic gel if G′>G″.

[0296] FIG. 9 presents the modulus of elasticity G′ and the viscosity modulus G″ of the EHUTMB/PIBUX mixture (90/10 as a function of the scanning frequency for a force of 3 Pa, at a temperature of 25° C.

[0297] FIG. 9 also presents the same analysis carried out after 7 months.

[0298] These results show:

[0299] firstly that G′>G″, that is to say that the gel is elastic,

[0300] secondly, after 7 months, the sample has moduli G′ and G″ comparable to those obtained at t=0.

[0301] In conclusion, the EHUTMB/PIBUX mixture in dodecane, at a 90/10 molar composition, has an elastic gel behaviour that is stable over time.

Example 8: Obtaining Gels in Oils

8.1. From an EHUTMB/PDMSUT Mixture in a Silicone Oil

[0302] The mixture of conventional bis-ureas having a trimethylbenzene spacer (EHUTMB) and functionalised bis-ureas of formula (III) having a toluene spacer (PDMSUT) was studied in a silicone oil, decamethylcyclopentasiloxane (D5), at a concentration of 25 g/l.

[0303] The results (FIG. 10) show that:

[0304] a solution comprising only EHUTMB is insoluble in silicone oil;

[0305] a solution comprising only PDMSUT is viscous but does not form a gel;

[0306] a PDMSUT/EHUTMB mixture [molar ratio 1:2] makes it possible initially to solubilise each EHUTMB and PDMSUT bis-urea in silicone oil and secondly makes it possible to obtain a stable gel.

[0307] Consequently these results show that a mixture of conventional bis-ureas having a trimethylbenzene spacer and functionalised bis-ureas having a toluene spacer makes it possible to obtain a stable gel in solvents wherein conventional bis-ureas are not soluble, such as silicone oil.

8.2. From an EHUTMB/PIBUX Mixture in PA06 Mineral Oil

[0308] The mixture of conventional bis-ureas having a trimethylbenzene spacer (EHUTMB) and functionalised bis-ureas of formula (II) having a xylene spacer (PIBUX) was studied in PA06 mineral oil at a concentration of 10 g/l.

[0309] The results show that:

[0310] a solution comprising only EHUTMB is insoluble in PA06 (formation of a white precipitate);

[0311] a solution comprising only PIBUX is viscous but does not form a gel;

[0312] an equimolar PIBUX/EHUTMB mixture makes it possible initially to solubilise each EHUTMB and PIBUX bis-urea in PA06 and secondly makes it possible to obtain a gel.

[0313] Consequently these results show that a mixture of conventional bis-ureas having a trimethylbenzene spacer and functionalised bis-ureas having a xylene spacer makes it possible to obtain a stable gel in solvents wherein conventional bis-ureas are not soluble, such as PA06.

Example 9: Obtaining Gels from an EHUTMB/POEUX Mixture in Acetonitrile

[0314] The mixture of conventional bis-ureas having a trimethylbenzene spacer (EHUTMB) and bis-ureas functionalised by polyethylene oxide chains of formula (II) having a xylene spacer (POEUX) was studied in acetonitrile at a concentration of 25 g/l.

[0315] The results show that:

[0316] a solution comprising only EHUTMB is insoluble in acetonitrile (formation of a white precipitate);

[0317] a solution comprising only POEUX is viscous but does not form a gel;

[0318] an equimolar POEUX/EHUTMB mixture makes it possible initially to solubilise each EHUTMB and POEUX bis-urea in acetonitrile and secondly makes it possible to obtain a gel.

[0319] Consequently these results show that a mixture of conventional bis-ureas having a trimethylbenzene spacer and functionalised bis-ureas having a xylene spacer makes it possible to obtain a stable gel in solvents wherein conventional bis-ureas are not soluble, such as acetonitrile.

Materials and Methods

Materials

[0320] The conventional bis-ureas and the functionalised bis-ureas employed in the present invention have previously been synthesised according to the protocols described in the literature: EHUT (Lortie, F. et al., Langmuir 2002, 18, 7218); EHUTMB (Isare, B. et al., J. Phys. Chem. B 2009, 113, 3360); EHUX (Isare, B. et al Langmuir 2012, 28(19), 7535); PIBUT (Pensec, S. et al., Macromolecules 2010, 43 (5), 2629); PIBUX (Thesis by Cécile Fonteneau, “Synthesis and properties of supramolecular polymers associated by hydrogen bonds by means of urea units, Université Pierre et Marie Curie: Paris, France, 2013); PABUX (Fonteneau, C. et al., Polym. Chem. 2014, 5(7), 2496); POEUX (Obert, E. et al., J. Am. Chem. Soc. 2007, 129(50), 15601) and PDMSUT (Colombani et al., Macromolecules 2005, 38, 1752).

[0321] The synthesis of PIBUTMB (polyisobutyleneureidotrimethylbenzene) was carried out in accordance with the following protocol:

1 eq. of 2,4,6-trimethyl-1,3-phenylenediisocyanate was dissolved in anhydrous dichloromethane under inert atmosphere, and the mixture was transferred via a cannula into a stirred solution of Kerocom® polyisobutylene amine (Kerocom® PIBA, 60% in solution in hydrocarbon, BASF, about 2 eq.) at ambient temperature under inert atmosphere. The reaction was left at rest for one night under agitation at ambient temperature, under inert atmosphere. A colourless viscous liquid was obtained and then the liquid was precipitated drop by drop on two occasions into ethyl acetate under agitation. A clear colourless oil was obtained after settling, and extracted with ethyl acetate. This oil was dried under vacuum (1.10.sup.−3 mbar) at 60° C. A colourless viscous oil was obtained (75%). The product obtained was characterised by steric exclusion chromatography in THF, at a concentration of 5 mg.ml.sup.−1 (results given in polystyrene equivalent) and by .sup.1H NMR.

TABLE-US-00004 PIBUTMB M.sub.n (g .Math. mol.sup.−1) 2804 M.sub.w (g .Math. mol.sup.−1) 3561 M.sub.w/M.sub.n 1.27

[0322] .sup.1H NMR (500 MHz, CDCl.sub.3-DMSO-d.sub.6, 50° C.) δ (ppm): 0.89-1.36 (m, 297 H, CH.sub.3—(CH.sub.2—C(CH.sub.3).sub.2).sub.nCH.sub.2—CH(CH.sub.3)—CH.sub.2; 2.04-2.09 (m, 9H, CH.sub.3-Ph); 3.08 (m, 4H, CH.sub.2—NH); 5.25 (s, 2H, CH.sub.2—NH); 6.68 (s, 2H, Ph-NH); 6.80 (s, 1H, Ph-H). DP=32.82; M.sub.n=2330 g.mol.sup.−1

Viscometry

[0323] The solutions for viscometric analysis were prepared in anhydrous toluene, previously filtered with 0.45 μm porosity filters. Solutions of functionalised bis-ureas were prepared at 80 g/l and conventional bis-urea solutions were prepared at concentrations of 5 mM. The solutions were agitated on a vibrating plate for 10 days. The solutions of EHUX were then heated to 80° C. under constant agitation for 12 hours in order to obtain a complete dissolution of the bis-ureas in solution. The solutions comprising conventional bis-ureas were mixed with functionalised bis-ureas by means of polymer chains and supplemented with a filtered solvent in order to obtain compositions comprising 1% mol, 5% mol and 10% mol conventional bis-ureas in the mixture, for a total solid concentration amounting to 40 g/l. The mixtures obtained were agitated for one night in order to homogenise the compositions before viscometric analysis at 20° C., 40° C., 60° C. and 80° C. The solvents used were also analysed in order to determine the relative viscosity of the samples. The apparatus used for these analyses was an Anton Paar AMVN falling-ball microviscometer.

Fourier Transform InfraRed Spectroscopy (FTIR)

[0324] The solutions were prepared by separately dissolving the conventional and functionalised bis-ureas by polymers in toluene (2 g/l). These solutions were next stirred on a vibrating plate for 10 days. Then these two solutions were mixed in accordance with the following conventional bis-urea/functionalised bis-urea compositions (% mol/% mol): 10/90; 20/80; 30/70; 40/60; 50/50; 60/40; 70/30; 80/20 and 90/10. The mixtures obtained were then stirred for one night in order to homogenise the compositions before FTIS analysis.

[0325] For the purpose of obtaining thermal equilibrium during analyses for each temperature studied, the measurements were made after 30 minutes of equilibration at the target temperature. The spectra of the solvent alone were conducted at each temperature under the same conditions as those used for the bis-urea solutions and then these measurements were subtracted from those of the samples.

[0326] The spectra were recorded by means of a Nicolet Is10 spectrometer equipped with a VTC21525 heating apparatus supplied by SPECAC, in 2 mm optical path vessels, equipped with CaF.sub.2 windows.

Rheology

[0327] The rheological analysis was carried out on a HAAKE Rheostress (RS) 600 rheometer, with a geometry of the flat cone type, 4 cm diameter, angle 2°, C35 2° Ti L04026 titanium.

[0328] The sample was placed on the surface of the rheometer. Then the geometry of the equipment was adjusted. The sample was heated to 80° C. for 15 minutes and then left at rest for 25° C. for 2 hours before force and frequency scanning.

Measurement of the Number Average Molar Mass M.sub.n and Mass Average M.sub.w

[0329] The number average molar mass M.sub.n and mass average M.sub.w of the macromolecular chains were determined by steric exclusion chromatography (SEC) in THF at a rate of 1 ml/minute. The apparatus used is the Viscotek Detector Array Model TDA 30 2 equipped with a light-diffusion detector (LALS: θ=7°, RALS: θ=90°; laser: λ=670 nm), a refractive index detector (λ=670 nm), a viscometric detector and three Polymer Laboratoires Miced C columns, thermostatically controlled at 40° C.