MATERIAL AND PROCESS FOR OBTAINING SAME

Abstract

The invention relates to a material comprising: a first crosslinked polymer forming a network, and a second linear polymer comprising n monomers, each of the monomers having the following formula I: (I), where m varies from 0 to 4, R is selected from hydrogen, an ethyl group and an alkyl group, and n is a non-zero natural integer, said material being such that it forms a semi-interpenetrating network wherein the second linear polymer is entangled in the network of the first polymer.

##STR00001##

Claims

1. A material comprising a first crosslinked polymer forming a network, said first polymer being obtained by thiol-ene reaction between a first composition comprising at least one first polyunsaturated carbon-based compound comprising at least one carbon-based chain comprising at least 5 carbon atoms, and at least one second compound comprising at least two SH functions, such that if the first polyunsaturated compound is bi-unsaturated, said second compound comprises at least three SH functions, and if the first polyunsaturated compound is at least tri-unsaturated, said second compound comprises at least two SH functions, and a second polymer consisting of n monomers, each of the monomers having the following formula I: ##STR00015## where m ranges from 0 to 4, R is selected from hydrogen and an especially linear C1-C5 alkyl group, and n is a non-zero natural integer greater than or equal to 100, or at least equal to 2, the n monomers being identical or different said material being such that it forms a semi-interpenetrating network in which the second polymer is entangled in the network of the first polymer.

2. The material according to claim 1, wherein said first at least one first polyunsaturated carbon-based compound comprising at least one carbon-based chain comprising at least 5 carbon atoms represents 40% or less by weight relative to the weight of said second polymer.

3. The material according to claim 1, wherein said first compound is an at least bi-unsaturated triglyceride, or a polyisoprene, essential fatty acids, or terpenes, especially carotene, farnesene, lycopene, phytoene, linalool or geraniol.

4. The material according to claim 1, wherein said first composition comprises at least one first polyunsaturated carbon-based compound comprising at least one unsaturated carbon-based chain is a composition comprising or consisting of one or more oils selected from vegetable oils, fish oils, and microbial oils resulting from microorganisms referred to as oleaginous.

5. The material according to claim 1, wherein the second polymer is a polyhydroxyalkanoate polymer with short side chains, or PHA-scl, consisting of n monomers of formula I, where m ranges from 1 to 3, R is selected from hydrogen, an ethyl group and a methyl group, and n is a non-zero natural integer greater than or equal to 100.

6. The material according to claim 1, wherein the compound comprising at least two SH functions is selected from the following compounds: trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis (3 -merc aptopropionate), pentaerythritol tetrakis(3 -merc aptobu tyrate), glycol dimercaptoacetate and tris[2-(3-mercaptopropionyloxy)ethyl]isocyanurate.

7. A process for preparing a material, said process comprising a) mixing: a first composition comprising at least one first polyunsaturated carbon-based compound comprising at least one unsaturated carbon-based chain, with at least one compound comprising at least two SH functions, at least one radical initiator, and at least one polymer consisting of n monomers, each of the monomers having the following formula I: ##STR00016## where m ranges from 0 to 4, R is selected from hydrogen, an ethyl group and an especially linear C1-C5 alkyl group, and n is a non-zero natural integer greater than or equal to 100, or at least equal to 2, the n monomers being identical or different, to obtain an initial composition, and b) crosslinking the first polymer between said at least one polyunsaturated carbon-based comprising at least one unsaturated carbon-based chain and the compound comprising at least two SH functions wherein the material comprises: a first crosslinked polymer forming a network, said first polymer being obtained by thiol-ene reaction between a first composition comprising at least one first polyunsaturated carbon-based compound comprising at least one carbon-based chain comprising at least 5 carbon atoms, and at least one second compound comprising at least two SH functions, such that if the first polyunsaturated compound is bi-unsaturated, said second compound comprises at least three SH functions, and if the first polyunsaturated compound is at least tri-unsaturated, said second compound comprises at least two SH functions, and a second polymer consisting of n monomers, each of the monomers having the following formula I: ##STR00017## where m ranges from 0 to 4, R is selected from hydrogen and an especially linear C1-C5 alkyl group, and n is a non-zero natural integer greater than or equal to 100, or at least equal to 2, the n monomers being identical or different, said material being such that it forms a semi-interpenetrating network in which the second polymer is entangled in the network of the first polymer.

8. The process according to claim 7, wherein the radical initiator is a photochemical radical initiator, especially selected from camphorquinone, ethyl 4-dimethylaminobenzoate, and 2,2-dimethoxy-2-phenylacetophenone.

9. The process according to claim 7, wherein said composition comprising at least one first polyunsaturated carbon-based compound comprising at least one unsaturated carbon-based chain is a composition comprising or consisting of one or more oils selected from vegetable oils, fish oils, and microbial oils resulting from microorganisms referred to as oleaginous.

10. The process according to claim 7, wherein the first composition comprising said first compound represents 40% or less by weight relative to the weight of said polymer consisting of n monomers of formula I.

11. The process according to claim 7, wherein the second polymer is a polyhydroxyalkanoate polymer with short side chains, or PHA-scl, of formula I, where m ranges from 1 to 3, R is selected from hydrogen, an ethyl group and a methyl group, and n is a non-zero natural integer greater than or equal to 100.

12. The process according to claim 7 , wherein the mixing step consists of, for 15 to 30 minutes in a suitable receptacle, bringing a composition comprising rapeseed oil and/or sunflower oil into contact with Trimethylolpropane tris(3-merc aptopropionate), poly(3-hydroxybutyrate) and/or poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and 2,2-dimethoxy-2-phenylacetophenone, and a solvent to form the initial composition.

13. (canceled)

14. A material comprising a first crosslinked polymer forming a network, said first polymer being obtained by thiol-ene reaction between a first composition comprising at least one first polyunsaturated carbon-based compound comprising at least one carbon-based chain comprising at least 5 carbon atoms, and at least one second compound comprising at least two SH functions, such that if the first polyunsaturated compound is bi-unsaturated, said second compound comprises at least three SH functions, and if the first polyunsaturated compound is at least tri-unsaturated, said second compound comprises at least two SH functions, and a second polymer consisting of n monomers, each of the monomers having the following formula I: ##STR00018## where m ranges from 0 to 4, R is selected from hydrogen and an especially linear C1-C5 alkyl group, and n is a non-zero natural integer greater than or equal to 100, or at least equal to 2, the n monomers being identical or different, said material being such that it forms a semi-interpenetrating network in which the second polymer is entangled in the network of the first polymer, wherein the material is used for the preparation of biodegradable and/or compostable food containers, packaging, coatings, for the preparation of injected parts or parts manufactured by extrusion or for the preparation of surface coatings.

15. The material of claim 14, wherein the material is used in human or animal surgery.

16. The material according to claim 4, wherein the vegetable oil is rapeseed oil, oleic rapeseed oil, sunflower oil, or a combination of rapeseed oil and sunflower oil.

17. The material according to claim 5, wherein said PHA-scls is poly-3-hydroxybutyrates or PHBs and/or poly(3-hydroxybutyrate-co-3-hydroxyvalerate)s or PHBHVs.

18. The process according to claim 11, wherein said PHA-scls is poly-3-hydroxybutyrates or PHBs and/or poly(3-hydroxybutyrate-co-3-hydroxyvalerate)s or PHBHVs.

19. The material of claim 14, wherein the coatings are surface coatings.

20. The material of claim 14, wherein the material is used for the manufacture of interior coatings for vehicles or else for the preparation of textiles or ropes

Description

FIGURE LEGEND

[0255] FIGS. 1A and 1B diagrammatically show the interpenetrating (FIG. 1A) and semi-interpenetrating networks (FIG. 1B).

[0256] FIG. 2 diagrammatically shows the structure of a semi-IPN PHA/oil/trithiol network. A shows a triglyceride of the oil, B shows a trithiol and C shows a linear PHA chain.

[0257] FIG. 3 shows the tensile curves obtained on different samples: A: of PHBHV alone, B: of PHBHV+10% oil, C: of PHBHV+20% oil, D: of PHBHV+30% oil and E: of PHBHV+40% oil. The abscissa axis shows the deformation in % and the ordinate axis shows the stress in MPa.

[0258] FIG. 4 shows the tensile curves obtained on different samples: A: of PHB alone, B: of PHB+10% oil without crosslinking, C: of PHB+20% crosslinked oil, and D: of PHB+20% crosslinked oil. The abscissa axis shows the deformation in % and the ordinate axis shows the stress in MPa.

[0259] FIG. 5 shows the tensile curves obtained on different samples: A: of PCL alone, B: of PCL+10% crosslinked oil, C: of PCL+20% crosslinked oil, D: of PCL+10% non-crosslinked oil, and E: of PCL+20% non-crosslinked oil. The abscissa axis shows the deformation in % and the ordinate axis shows the stress in MPa.

[0260] FIG. 6 shows the tensile curves obtained on different samples: A: of PLA alone, B: of PLA+10% crosslinked oil, and C: of PLA+20% crosslinked oil. The abscissa axis shows the deformation in % and the ordinate axis shows the stress in MPa.

[0261] FIG. 7 shows the curves of a thermogravimetric analysis (TGA) for different products: A: sunflower oil, B: crosslinked sunflower oil, C: PHB network+sunflower oil, and D: PHB alone. The abscissa axis shows the temperature in C. and the ordinate axis shows the mass loss in %.

[0262] FIG. 8 shows the tensile curves obtained on different samples: A: of PHBHV alone, B: of PHBHV+10% crosslinked polyisoprene, C: of PHBHV+20% crosslinked polyisoprene, D: of PHBHV+30% crosslinked polyisoprene and E: of PHBHV+40% crosslinked polyisoprene. The abscissa axis shows the deformation in % and the ordinate axis shows the stress in MPa.

[0263] FIGS. 9A and 9B represent a comparison of films obtained with PHB.

[0264] FIG. 9A shows a photograph of a film obtained from 100% PHB under a heating press.

[0265] FIG. 9B shows a photograph of a semi-IPN network PHB/linalool/trithiol obtained by heating press.

[0266] FIG. 10 shows the tensile curves obtained on different samples: A: from non-irradiated irradiated PHB/linalool and B: from irradiated PHB/linalool. The abscissa axis shows the deformation in % and the ordinate axis shows the stress in MPa.

[0267] FIG. 11 shows the tensile curves obtained on different samples: A: of PHBHV alone and B: of PHBHV/unsaturated lignin, trithiol. The abscissa axis shows the deformation in % and the ordinate axis shows the stress in MPa.

EXAMPLES

Example 1

Preparation of a PHA/Sunflower Oil Material

[0268] The inventors prepared semi-interpenetrating networks comprising PHAs and crosslinked networks based on oil. The crosslinking of the oil was carried out by thiol-ene reaction. This reaction involves the addition of the thiol functions of trimethylolpropane tris(3-mercaptopropionate), a polyfunctional trithiol, to the double bonds of triglycerides. This thiol-ene reaction is initiated by a photoinitiator, 2,2-dimethoxy-2-phenylacetophenone (DMPA) under photochemical activation. The incorporation of oil in determined proportions (10 to 40% by weight relative to the polymer) is intended to confer novel properties on the PHAs.

[0269] 1. Experimental Conditions

[0270] The inventors tested various PHAs: P3HB ([OCH(CH.sub.3)CH.sub.2CO]), P3HB88HV12 (obtained from Goodfellow; [-OCH(CH.sub.3)CH.sub.2CO] at 88%; [CH(CH.sub.2CH.sub.3)CH.sub.2CO] at 12%) and PHO (obtained from EMPA; [OCH(C.sub.5H.sub.11)CH.sub.2CO]).

[0271] The experimental conditions for forming the semi-IPN network are collated in the following table:

[0272] First of all, PHBHV was precipitated in petroleum ether to extract the plasticizer, and PHB, sparingly soluble in the usual organic solvents (due to its high crystallinity), was heated to 60 C. in the dichloromethane solution for 5 min before adding the other reagents. The trithiol mass was calculated to have a ratio n.sub.SH/CC=1.

[0273] 2. PHB and PHBHV Results

[0274] 2.1. Mechanical Tests

[0275] Mechanical tests were carried out on standard test specimens, using a tensile testing machine (Instron, model 5965). The test specimens are pulled at a fixed speed of 2 mm/min. The principle of the tensile test is based on a uniaxial stress up to the breaking point of the test specimen in order to determine the mechanical characteristics thereof, such as Young's E modulus (rigidity of the material), the elongation at break, and the tensile strength. The results are reported in the following table and in FIGS. 3 and 4.

[0276] The incorporation of the oil into the polyester without crosslinking modifies the mechanical properties of the PHA. Indeed, the inventors observed a significant decrease in the Young's modulus (characteristic of the hardness of the material) going from 1011 to 516 MPa for the PHBHV and 954 to 739 MPa for the PHB. The oil impedes the crystallization of the polymer, resulting in a decrease in the modulus.

[0277] When the oil is crosslinked within the polymer, the inventors observed a more marked decrease in the Young's modulus (between 250 and 350 MPa for the PHBHV films and 250 MPa for the PHB films) but, on the other hand, a considerable increase in elongation at break is observed (up to 150% of its initial length). The material prepared therefore has elastic properties contrary to the initial polymer and this phenomenon is particularly marked.

[0278] The crosslinked oil (100%) forms a transparent gel, without hold and which is very tacky. When PHB (50%) is added, the film becomes easily detachable and non-tacky, and the latter strongly resembles rubber but with an absence of hold (the film tears easily) and the mechanical tests could not be realized.

[0279] 2.2. Thermal Properties

[0280] The inventors studied the thermal properties of the PHB/oil films, with an oil load ranging from 50% to 100%, in order to discuss the influence of the oil in the co-network. Thermal degradation temperatures were evaluated by thermogravimetric analysis (TGA). The tests were carried out at 20 C./min over a temperature range extending from 20 to 800 C., under air. The shape of the thermograms obtained is characteristic of the structure and composition of the material.

[0281] The TGA results shown in FIG. 7 indicate that PHB degrades at close to 250 C. In the presence of oil, the degradation temperature is shifted towards high temperatures. The material only begins to decompose from 300 C. and gradually degrades up to 500 C. The first step of thermal degradation is attributed to the PHB and the second to the decomposition of the crosslinked oil. The incorporation of oil thus makes it possible to improve the thermal stability of the structure.

[0282] 2. PHO Results

[0283] In this study, the inventors also investigated the formation of a semi-IPN network from a PHA with medium side chains (PHA-mcl).

[0284] The procedure is identical to that for the PHA-scls described above.

[0285] Conclusion

[0286] The combination of PHA-scls and crosslinked oil enabled the synthesis of a flexible material that had never been observed in the literature. According to the results obtained, the incorporation of 10% crosslinked oil was sufficient to improve the elastic properties of the material. This property makes it possible to envisage the competitiveness of this product with other polymers such as flexible PVC (flexible polyvinyl chloride), LDPE (low-density polyethylene) or PP (polypropylene). The comparison of the thermomechanical properties of these various polymers is presented in the table summarizing the thermal and mechanical properties of the usual polymers below.

[0287] The advantages of the synthesized material are its transparent color, its fruity odor and a high melting point (M.P.=165 C.) compared with that of PVC (M.P.<150 C.) or LDPE (M.P.=115 C.), which makes it possible to broaden its field of application. In addition, in contrast to LDPE and PVC, PHAs have better UV resistance.

[0288] It is also important to note that the mechanical properties of the pure polymers (without chemical modification) with which the inventors worked are not entirely similar to what has been described in the literature. Indeed, the Young's modulus of the PHBHV obtained by the inventors during their tests is less than the theoretical value (1100 MPa instead of 1500 MPa for a copolymer consisting of 12% HV units). The same applies to the PHB, for which they obtained a modulus of approximately 950 MPa instead of 3500 MPa. This difference may be due to the conditions under which they worked.

[0289] The following table summarizes the thermal and mechanical properties of the usual polymers, and also examples of materials according to the invention.

Example 2

Preparation of a PLA or PCL/Oil Material

[0290] The inventors also formed semi-IPN networks from polylactic acid or PLA or from polycaprolactone or PCL, working under the same operating conditions as those described for the PHAs in example 1.

[0291] The results are summarized in tables 1 and 2 and shown in FIGS. 5 and 6. A decrease in Young's modulus and in the tensile strength and an improvement in elongation at break are observed in both cases. These results coincide with those obtained with the PHAs. It is therefore possible to use this process using polymers other than PHAs.

[0292] This process may be applicable to other polymer families such as polyolefins (PE-HD, PP), rigid polyvinyl chlorides, styrenics (PS), polyacrylics (PMMA), polyamides, polycarbonates, saturated polyesters (PBT, PET, polyalkylene terephthalates), etc.

[0293] The following two tables respectively show the tensile results obtained on PCL/oil/trithiol and PLA/oil/trithiol films.

Example 3

Preparation of a Polyisoprene/Oil Material

[0294] The inventors also formed semi-IPN networks from PHA and polyisoprene, working under the same operating conditions as those described for example 1.

[0295] The results are shown in FIG. 8. A decrease in Young's modulus and tensile strength and an improvement in elongation at break (increase of 170% from its initial length) are observed. These results coincide with those obtained with the PHA/oil networks. It is therefore possible to use this process using polyunsaturated compounds other than oils.

Example 4

Preparation of a PHA/Oil Material by Extrusion

[0296] The extrusion was carried out using a HAAKE Minilab II Microcompounder machine. The equivalent of 7.5 cm.sup.3 of PHA/oil/photoactivator/trithiol mixture is inserted into the feed hopper. The temperature of the oven is set at 165 C. and the speed of rotation of the screws at 50 rpm. The injection of the material is then injected at 170 C. for 30 seconds before being recovered in a mold.

Example 5

Preparation of a PHA/Essential Oil (Linalool) Material

[0297] The inventors also formed semi-IPN networks from PHA and linalool (3,7-dimethyl-1,6-octadien-3-o1). Firstly, a homogeneous solution containing the following reagents: [0298] linalool, [0299] trithiol (n.sub.CC/n.sub.SH=1), and [0300] DMPA (5 wt %),
was prepared by dissolving the compounds at 50 C. for 2 min.

[0301] Subsequently, 0.3 g of PHB was mixed with 25% by weight of the above solution (which represents 10% by weight of linalool). Linalool makes it possible to dispense with the addition of CH.sub.2Cl.sub.2 to dissolve the PHB. The mixture was ground with a mortar to homogenize it. The mixture was heated to 150 C. for 2 min, then pressed at 1000 kg/ton ((SPECAC) mechanical press) for 2 min at 150 C. to obtain a film.

[0302] The inventors then irradiated the film under a UV lamp (Hamamatsu LC8 lamp (L8251) at a wavelength of 250 to 450 nm) for 300 seconds to obtain the semi-interpenetrating network. The films obtained are shown in FIGS. 9A and 9B. As shown in these photos, while the 100% PHB is very brittle, opaque and hard, the PHB/linalool/trithiol semi-IPN network is flexible, ductile and transparent. The mechanical tensile tests obtained on the PHB films and on the PHB/linalool films are indicated in the table below:

[0303] These data are shown in FIG. 10.

[0304] The formulation with the terpene (linalool) makes it possible to dispense with the use of a solvent during the preparation of the material. The material obtained has a more flexible character than PHB alone, or the PHB/linalool without irradiation, with an elongation at break which increases from 6 to 68% or from 18.4 to 68%.

Example 6

Preparation of a PHA/Modified Lignin Material

[0305] The inventors functionalized Kraft lignin by causing an allyl bromide to act on the alcohol functions in order to obtain a lignin containing unsaturations in accordance with the following reaction scheme:

##STR00014##

[0306] This unsaturated lignin was subsequently used as a reagent to form the semi-IPN network with trithiol, as in the previous examples.

[0307] The mechanical tensile tests obtained on the PHBHV films and on the PHB/linalool films are indicated in the table below:

[0308] These data are shown in FIG. 11.

[0309] The results obtained from the chemically modified lignin show that the semi-IPN network can be obtained from any molecule or polymer to which at least two unsaturations are added.

[0310] The invention is not limited to the embodiments presented and other embodiments will become clearly apparent to those skilled in the art.