Poly(amide-imide) copolymer, method of manufacturing the same, poly(amide-imide) copolymer film, window for display device, and display device

1. A poly(amide-imide) copolymer, comprising:

an amide structural unit comprising an amide bond included in a polymer main chain, and imide structural units comprising an imide bond included in the polymer main chain,

wherein the imide structural units comprise:

a first imide structural unit comprising a moiety cross-linked to an adjacent polymer main chain through an amide bond, and

a second imide structural unit, which is not cross-linked to an adjacent polymer main chain,

wherein the first imide structural unit comprises a structural unit represented by Chemical Formula 1

wherein, in Chemical Formula 1,

X is the same or different in each structural unit and is independently a substituted or unsubstituted C6 to C20 monocyclic aromatic group, a substituted or unsubstituted C4 to C20 monocyclic non-aromatic group, a substituted or unsubstituted C8 to C20 condensed polycyclic aromatic group, a substituted or unsubstituted C6 to C20 condensed polycyclic non-aromatic group, a substituted or unsubstituted C6 to C20 non-condensed polycyclic aromatic group, a substituted or unsubstituted C6 to C20 non-condensed polycyclic non-aromatic group, or a combination thereof, wherein each of the substituted or unsubstituted C6 to C20 non-condensed polycyclic aromatic group and the substituted or unsubstituted C6 to C20 non-condensed polycyclic non-aromatic group are linked by a single bond or a linking group comprising a substituted or unsubstituted fluorenyl group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR a (OH), SiR b R c , or (CR d R e ) p (1≤p≤10), wherein R a to R e are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group,

Y is the same or different in each structural unit and is independently a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C3 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C3 to C20 heteroarylene group, or a combination thereof, and

R 11 is the same or different in each structural unit and is independently a single bond or a divalent organic group comprising a substituted or unsubstituted C6 to C30 aromatic or non-aromatic ring, wherein the aromatic or non-aromatic ring is present as a single ring; two or more aromatic or non-aromatic rings are condensed to provide a condensed polycyclic aromatic group; or two or more aromatic or non-aromatic rings are linked by a single bond or a linking group comprising a substituted or unsubstituted fluorenyl group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR f (OH), SiR g R h , or (CR i R j ) p (1≤p≤10) to provide a non-condensed polycyclic aromatic group, wherein R f to R j are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group, and

* is a linking point of the polymer main chain.

2. The poly(amide-imide)copolymer of claim 1 , wherein the structural unit represented by Chemical Formula 1 comprises a structural unit represented by Chemical Formula 1a;

wherein, in Chemical Formula 1a,

R 10 is the same or different in each structural unit and is independently a single bond or a linking group comprising a fluorenylene group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR a (OH), SiR b R c , or (CR d R e ) p (1≤p≤10), wherein R a to R e are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group,

Y is the same or different in each structural unit and is independently a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C3 to C20 cycloalkylene group, a substituted or unsubstituted C3 to C20 heterocycloalkylene group, a substituted or unsubstituted C6 to C20 arylene group, a substituted or unsubstituted C3 to C20 heteroarylene group, or a combination thereof,

R 11 is the same or different in each structural unit and is independently a single bond or a divalent organic group comprising a substituted or unsubstituted C6 to C30 aromatic or non-aromatic ring, wherein the aromatic or non-aromatic ring is present as a single ring; two or more aromatic or non-aromatic rings are condensed to provide a condensed polycyclic aromatic group; or two or more aromatic or non-aromatic rings are linked by a single bond or a linking group comprising a substituted or unsubstituted fluorenyl group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR f (OH), SiR g R h , or (CR i R j ) p (1≤p≤10) to provide a non-condensed polycyclic aromatic group, wherein R f to R j are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group,

R 12 and R 13 are the same or different in each structural unit and are independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 haloalkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heterocyclic group, a substituted or unsubstituted silyl group, a halogen, a cyano group, a hydroxy group, a nitro group, or a combination thereof,

n7 and n8 are the same or different in each structural unit and are independently an integer ranging from 0 to 3, and

* is a linking point of the polymer main chain.

3. The poly(amide-imide)copolymer of claim 2 , wherein the structural unit represented by Chemical Formula 1a comprises at least one of a structural unit represented by Chemical Formula 1aa or a structural unit represented by Chemical Formula 1ab

4. The poly(amide-imide) copolymer of claim 1 , wherein the second imide structural unit comprises a structural unit represented by Chemical Formula 3

wherein, in Chemical Formula 3,

X is the same or different in each structural unit and is independently a substituted or unsubstituted C6 to C20 monocyclic aromatic group, a substituted or unsubstituted C4 to C20 monocyclic non-aromatic group, a substituted or unsubstituted C8 to C20 condensed polycyclic aromatic group, a substituted or unsubstituted C6 to C20 condensed polycyclic non-aromatic group, a substituted or unsubstituted C6 to C20 non-condensed polycyclic aromatic group, a substituted or unsubstituted C6 to C20 non-condensed polycyclic non-aromatic group, or a combination thereof, wherein each of the substituted or unsubstituted C6 to C20 non-condensed polycyclic aromatic group and the substituted or unsubstituted C6 to C20 non-condensed polycyclic non-aromatic group are linked by a single bond or a linking group comprising a substituted or unsubstituted fluorenyl group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR a (OH), SiR b R c , or (CR d R e ) p (1≤p≤10), wherein R a to R e are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group,

R 11 is the same or different in each structural unit and is independently a single bond or a divalent organic group comprising a substituted or unsubstituted C6 to C30 aromatic or non-aromatic ring, wherein the aromatic or non-aromatic ring is present as a single ring; two or more aromatic or non-aromatic rings are condensed to provide a condensed polycyclic aromatic group; or two or more aromatic or non-aromatic rings are linked by a single bond or a linking group comprising a substituted or unsubstituted fluorenyl group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR f (OH), SiR g R h , or (CR i R j ) p (1≤p≤10) to provide a non-condensed polycyclic aromatic group, wherein R f to R j are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group, and

* is a linking point of the polymer main chain.

5. The poly(amide-imide) copolymer of claim 4 , wherein the second imide structural unit comprises a structural unit represented by Chemical Formula 3a:

wherein, in Chemical Formula 3a,

R 10 is the same or different in each structural unit and is independently a single bond or a linking group comprising a fluorenylene group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR a (OH), SiR b R c , or (CR d R e ) p (1≤p≤10), wherein R a to R e are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group,

R 11 is the same or different in each structural unit and is independently a single bond or a divalent organic group comprising a substituted or unsubstituted C6 to C30 aromatic or non-aromatic ring, wherein the aromatic or non-aromatic ring is present as a single ring; two or more aromatic or non-aromatic rings are condensed to provide a condensed polycyclic aromatic group; or two or more aromatic or non-aromatic rings are linked by a single bond or a linking group comprising a substituted or unsubstituted fluorenyl group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR a (OH), SiR g R h , or (CR i R j ) p (1≤p≤10) to provide a non-condensed polycyclic aromatic group, wherein R f to R j are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group,

R 12 and R 13 are the same or different in each structural unit and are independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 haloalkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heterocyclic group, a substituted or unsubstituted silyl group, a halogen, a cyano group, a hydroxy group, a nitro group, or a combination thereof,

n7 and n8 are the same or different in each structural unit and are independently an integer ranging from 0 to 3, and

* is a linking point of the polymer main chain.

6. The poly(amide-imide) copolymer of claim 5 , wherein the second imide structural unit comprises at least one of a structural unit represented by Chemical Formula 3aa or a structural unit represented by Chemical Formula 3ab:

wherein, in Chemical Formulae 3aa and 3ab, * is a linking point of the polymer main chain.

7. The poly(amide-imide) copolymer of claim 1 , wherein the amide structural unit comprises a structural unit represented by Chemical Formula 4:

wherein, in Chemical Formula 4,

L is the same or different in each structural unit and is independently a single bond, —CONH—, -Ph-CONH-Ph- or —NHCO-Ph-CONH—, wherein “Ph” is a substituted or unsubstituted phenylene group,

R 2 is the same or different in each structural unit and is independently a divalent organic group comprising a substituted or unsubstituted C6 to C30 aromatic or non-aromatic ring, wherein the aromatic or non-aromatic ring is present as a single ring; two or more aromatic or non-aromatic rings are condensed to provide a condensed polycyclic aromatic or condensed polycyclic non-aromatic group; or two or more aromatic or non-aromatic rings are linked by a single bond or a linking group comprising a substituted or unsubstituted fluorenyl group, O, S, C(═O), OC(═O), S(═O), S(═O) 2 , C(═O)NH, CR k (OH), SiR l R m , or (CR n R o ) p (1≤p≤10) to provide a non-condensed polycyclic aromatic or non-condensed polycyclic non-aromatic group, wherein R k to R o are independently hydrogen, a C1 to C30 alkyl group, a C1 to C30 haloalkyl group, a halogen, or a hydroxy group,

R 6 to R 9 are the same or different in each structural unit and are independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 haloalkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heterocyclic group, a substituted or unsubstituted silyl group, a halogen, a cyano group, a hydroxy group, a nitro group, or a combination thereof,

n3 and n4 is the same or different in each structural unit and is independently an integer ranging from 0 to 4,

n5 and n6 are the same or different in each structural unit and are independently an integer ranging from 0 to 3,

n3+n5 is the same or different in each structural unit and is independently an integer ranging from 0 to 4,

n4+n6 is the same or different in each structural unit and is independently an integer ranging from 0 to 4, and

* is a linking point of the polymer main chain.

8. The poly(amide-imide) copolymer of claim 7 , wherein the amide structural unit comprises at least one of a structural unit represented by Chemical Formula 4a or a structural unit represented by Chemical Formula 4b;

wherein, in Chemical Formulae 4a and 4b, * is a linking point of the polymer main chain.

9. A poly(amide-imide) copolymer film comprising the poly(amide-imide) copolymer of claim 1 .

10. The poly(amide-imide) copolymer film of claim 9 , wherein the poly(amide-imide) copolymer film has a modulus of greater than or equal to about 5.8 gigapascals.

11. The poly(amide-imide) copolymer film of claim 10 , wherein the poly(amide-imide) copolymer film has a light transmittance of greater than or equal to about 80% and a yellow index of less than or equal to about 4.5.

12. A window for a display device comprising the poly(amide-imide) copolymer film of claim 9 .

13. A display device comprising the window for a display device of claim 12 .

14. A display device comprising the poly(amide-imide) copolymer film of claim 9 .