Elastomeric polymer material with shape memory properties and method for preparing such a material

1 . A method for preparing a polyester polymer material, comprising successively, the steps of:

preparing a reaction medium comprising a mixture of:

at least one monomer selected from w-hydroxylated fatty acids, or esters of a w-hydroxylated fatty acid and an alcohol having a linear or branched, saturated or unsaturated, optionally substituted, aliphatic chain, said aliphatic chain comprising from 1 to 18 carbon atoms; and

at least one phenolic compound, the total phenolic compound(s) content, determined by spectrophotometric analysis after reaction with a Folin-Ciocalteu reagent, with respect to a standard range of gallic acid, lying in a range of values from 0.3 to 42 mg equivalent of gallic acid per gram of said mixture,

and heating this reaction medium to carry out the polymerization of said monomer and of said phenolic compound and cross-linking of the polymer thus formed.

2 . The method according to claim 1 , wherein said reaction medium is free from catalyst.

3 . The method according to claim 1 , wherein at least an initial phase of the heating step is implemented under reduced pressure.

4 . The method according to claim 3 , wherein at least an initial phase of the heating step is implemented at a pressure between 0 and 900 mbar.

5 . The method according to claim 1 , wherein said heating step is implemented in a temperature range between 120 and 200° C., for a period of at least 4 hours.

6 . The method according to claim 1 , wherein said mixture contains at least one phenolic compound selected from the group consisting of hydroxybenzoic acids, hydroxycinnamic acids and flavonoids, and any combination of such phenolic compounds.

7 . The method according to claim 1 , wherein said mixture contains at least p-coumaric acid and/or naringenin.

8 . The method according to claim 1 , wherein said monomer is a dihydroxylated fatty acid or an ester of a dihydroxylated fatty acid and an alcohol having a linear or branched, saturated or unsaturated, optionally substituted, aliphatic chain, comprising from 1 to 18 carbon atoms.

9 . The method according to claim 1 , wherein said mixture is obtained by depolymerization of cutin, so as to obtain a monomers extract, recovery of the monomers extract obtained and purification of said monomers extract to partially eliminate the phenolic compounds contained in said monomers extract, so as to obtain for said monomers extract a phenolic compound(s) content lying in said range of values.

10 . A polyester polymer material obtained by the method according to claim 1 ,

comprising as constituent monomer units at least one w-hydroxylated fatty acid and at least one phenolic compound;

having a semicrystalline structure comprising stacks of crystalline phases of the hexagonal type; and

containing a quantity of 0.03 to 4.2% by weight of phenolic compound(s) units, with respect to the total weight of said polymer material, this quantity being determined by quantitative analysis of the total content of phenolic compound(s) in the mixture used for preparing said polymer material, by spectrophotometric analysis after reaction with a Folin-Ciocalteu reagent, with respect to a standard range of gallic acid, this content lying in a range of values from 0.3 to 42 mg equivalent of gallic acid per gram of mixture.

11 . The polyester polymer material according to claim 10 , wherein the melting point of said crystalline phases is above 30° C.

12 . The method according to claim 4 , wherein the pressure is between 400 and 800 mbar.

13 . The method according to claim 8 , wherein said monomer is 10,16-dihydroxyhexadecanoic acid or the methyl or ethyl ester thereof.

14 . The method according to claim 9 , wherein said cutin is tomato cutin.

15 . The polyester polymer material according to claim 11 , wherein the melting point of said crystalline phases is between 3° and 70° C.