Self-healing polymers
The present invention relates to Diels-Alder-based polymers comprising the reaction product of a composition comprising a polymaleimide and a monomeric unit. The Diels-Alder-based polymers may be self-healing polymers. The Diels-Alder-based polymers may be used in 3D printing, flexible electronics and soft robotics. Furthermore, the present invention relates to structures comprising said Diels-Alder-based polymers.
1 . A Diels-Alder-based polymer comprising the reaction product of a composition comprising a polymaleimide and a monomeric unit according to formula (I):
wherein:
R 1 , R 2 , R 3 , and R 4 are independently selected from H or C 1 -C 4 alkyl;
R 5 , R 6 , R 7 , R 8 , R 9 , and R 10 are independently selected from H or A;
each A independently represents a furan-comprising functional group;
L 1 , L 2 , and L 3 are independently selected from a direct bond or a divalent C 1 -C 4 alkyl;
n is 0 or 1; and
x+y+z is an integer selected from 1 to 75;
wherein the polymaleimide and the monomeric unit each comprise a functionality of at least 2; the sum of the functionalities of both the polymaleimide and the monomeric unit is at least 4.6; and a maleimide-to-furan stoichiometric ratio between the polymaleimide and the monomeric unit ranges from 0.20 to 0.65.
2 . The Diels-Alder-based polymer according to claim 1 , comprising a maleimide or a furan functionality of from 3 to 8.
3 . The Diels-Alder-based polymer according to claim 1 , wherein the furan-comprising functional group is selected from furfuryl ethers, furfuryl glycidyl ether, furfuryl alcohols, 2-furoic acid, and 3-furoic acid.
4 . The Diels-Alder-based polymer according claim 1 , wherein the polymaleimide is selected from 1,1′-(methylenedi-4,1-phenylene)bismaleimide, N,N′-(1,4-phenylene)dimaleimide, N,N′-(1,3-phenylene)dimaleimide, and polyphenylmethanebismaleimide.
5 . The Diels-Alder-based polymer according to claim 1 , wherein R 1 , R 2 , R 3 , and/or R 4 are CH 3 .
6 . The Diels-Alder-based polymer according to claim 1 , wherein L 1 , L 2 , and/or L 3 are —CH 2 —.
7 . A composition comprising the Diels-Alder-based polymer according to claim 1 .
8 . The composition according to claim 7 , further comprising a radical scavenger.
9 . The composition according to claim 8 , wherein the radical scavenger is selected from hydroquinone butylated hydroxytoluene, 4-tert-butylcatechol, and methyl-p-benzoquinone.
10 . The composition according to claim 7 , wherein the composition is a self-healing material.
11 . A 2D or 3D structure comprising the composition according to claim 10 .
12 . A method of preparing the Diels-Alder polymer of claim 1 , comprising:
(a) preparing a composition comprising a polymaleimide and a monomeric unit according to formula (I):
wherein:
R 1 , R 2 , R 3 , and R 4 are independently selected from H or C 1 -C 4 alkyl;
R 5 , R 6 , R 7 , R 8 , R 9 , and R 10 are independently selected from H or A;
each A independently represents a furan-comprising functional group;
L 1 , L 2 , and L 3 are independently selected from a direct bond or a divalent C 1 -C 4 alkyl;
n is 0 or 1; and
x+y+z is an integer selected from 1 to 75;
wherein the polymaleimide and the monomeric unit each comprise a functionality of at least 2; the sum of the functionalities of both the polymaleimide and the monomeric unit is at least 4.6; and a maleimide-to-furan stoichiometric ratio between the polymaleimide and the monomeric unit ranges from 0.20 to 0.65; and
(b) carrying out a Diels-Alder polymerization reaction between the polymaleimide and the monomeric unit according to formula (I).
13 . The method according to claim 12 , wherein the Diels-Alder polymer comprises a maleimide or a furan functionality of from 3 to 8.
14 . The method according to claim 12 , wherein the furan-comprising functional group is selected from furfuryl ethers, furfuryl glycidyl ether, furfuryl alcohols, 2-furoic acid, and 3-furoic acid.
15 . The method according to claim 12 , wherein the polymaleimide is selected from 1,1′-(methylenedi-4,1-phenylene)bismaleimide, N,N′-(1,4-phenylene)dimaleimide, N,N′-(1,3-phenylene)dimaleimide, and polyphenylmethanebismaleimide.
16 . The method according to claim 12 , wherein R 1 , R 2 , R 3 , and/or R 4 are CH 3 .
17 . The method according to claim 12 , wherein L 1 , L 2 , and/or L 3 are —CH 2 —.
18 . The method according to claim 12 , wherein the composition further comprises a radical scavenger.
19 . The Diels-Alder-based polymer according claim 1 , wherein the Diels-Alder-based polymer is a self-healing polymer and self-healing occurs at temperatures below 30° C.
20 . The Diels-Alder-based polymer according claim 1 , wherein the Diels-Alder-based polymer has a self-healing efficiency of at least 80% after 7 days at 25° C.