(Meth)acrylate functionalized poly(meth)acrylate-block-polyimide- block-poly(meth)acrylate copolymer, preparation method and use thereof

1. A (meth)acrylate-functionalized block-copolymer represented by Formula I:

wherein m and n each independently represent an integer from about 1 to about 50, provided that m and n are not both 1 at the same time;

each R 1 and R 14 is independently selected from hydrogen or methyl;

each R 2 is independently selected from a C 1 -C 12 alkyl group;

each R 3 is independently selected from —CH(CH 3 )— or —C(CH 3 ) 2 —;

each R 4 is independently selected from a C 1 -C 12 alkylene group;

R 5 is a divalent linking unit selected from a C 6 -C 30 cycloaliphatic group or a C 6 -C 30 arylene group; and

each A is a tetravalent linking unit independently selected from a C 4 -C 14 aliphatic group, a C 4 -C 30 cycloaliphatic group, a C 6 -C 30 aryl group, an ether group, a sulfone group, a sulphide group, an amide group and an ester group.

2. The copolymer according to claim 1 , wherein each R 2 is independently selected from a C 1 -C 6 alkyl group.

3. The copolymer according to claim 1 , wherein each R 4 is independently selected from a C 1 -C 6 alkylene group.

4. The copolymer according to claim 1 , wherein each A is independently selected from the following groups:

wherein R 6 is a divalent linking unit and R 6 is at the 3,3′-, 3,4′-, 4,3′- or 4,4′-positions of the benzene rings,

R 6 is selected from —O—, —S—, —C(O)—, —SO 2 —, —SO—, C 1 -C 20 alkylene group, halogenated C 1 -C 20 alkylene group, C 1 -C 20 perfluoroalkylene group and groups represented by —O—Z—O—, wherein Z is a divalent linking group selected from the following groups:

wherein R 7 is selected from —O—, —S—, —C(O)—, —SO 2 —, —SO—, a C 1 -C 20 alkylene group, a halogenated C 1 -C 20 alkylene group and a C 1 -C 20 perfluoroalkylene group.

5. The copolymer according to claim 1 , wherein R 5 is selected from the following groups:

wherein R 8 to R 13 are each independently selected from a C 1 -C 20 alkylene group, a halogenated derivative of a C 1 -C 20 alkylene group and a C 1 -C 20 perfluoroalkylene group.

6. The copolymer according to claim 1 , wherein the copolymer is represented by any one of Formula II to Formula IV:

wherein R 1 to R 4 , R 14 , m and n are each as defined in claim 1 , R 6 is selected from —O—, —S—, —C(O)—, —SO 2 —, —SO—, C 1 -C 20 alkylene groups, halogenated C 1 -C 20 alkylene groups, C 1 -C 20 perfluoroalkylene groups, and groups represented by —O—Z—O—, wherein Z is a divalent linking group selected from the following groups:

wherein R 7 is selected from —O—, —S—, —C(O)—, —SO 2 —, —SO—, C 1 -C 20 alkylene groups and halogenated C 1 -C 20 alkylene groups (including C 1 -C 20 perfluoroalkylene groups),

R 10 is selected from C 1 -C 20 alkylene groups, halogenated derivatives of C 1 -C 20 alkylene groups; and C 1 -C 20 perfluoroalkylene groups,

R 11 is selected from C 1 -C 20 alkylene groups, halogenated derivatives of C 1 -C 20 alkylene groups; and C 1 -C 20 perfluoroalkylene groups.

7. The copolymer according to claim 1 , having a number average molecular weight (Mn) from 2,000 to 1,000,000 Daltons as measured by GPC.

8. The copolymer according to claim 1 , wherein the number ratio of the polyimide block to the poly(meth)acrylate block, (m:2n) is 1:1 to 1:100.

9. A method for preparing the block copolymer according to claim 1 , comprising:

reacting a diamine, a dianhydride and a monoamine to form a polyamic acid according to scheme 1 below;

dehydrating the polyamic acid to form a polyimide;

reacting the polyimide and a (meth)acrylate to form a bromine-terminated poly(meth)acrylate-block-polyimide-block-poly(meth)acrylate copolymer represented by formula V;

and

reacting the bromine-terminated poly(meth)acrylate-block-polyimide-block-poly(meth)acrylate copolymer with (meth)acrylic acid to form the (meth)acrylate-functionalized poly(meth)acrylate-block-polyimide-block-poly(meth)acrylate copolymer represented by Formula I,

wherein R 1 to R 5 , R 14 , A, m and n are each as defined in claim 1 .

10. A photocurable adhesive composition comprising the copolymer according to claim 1 , wherein the adhesive composition is a liquid optically clear adhesive.

11. The adhesive composition according to claim 10 , further comprising a (meth)acrylate monomer and/or a photo initiator.

12. The adhesive composition according to claim 10 , further comprising a mono-functional or di-functional (meth)acrylate monomer and/or a photo initiator.

13. The adhesive composition according to claim 10 , further comprising a (meth)acrylate monomer and/or a photo initiator selected from benzoin ether photoinitiator, benzil ketal photoinitiator, acetophenone photoinitiator, anthraquinone photoinitiator, thioxanthone photoinitiator, benzophenone photoinitiator, acyl phosphine oxide photoinitiator, benzoate photoinitiator and any combination thereof.

14. An article comprising two substrates bonded together by cured reaction products of the adhesive composition according to claim 10 .