Amide and imide photoinitiators

1. A polymer comprising of one or more units of formula (I) and one or more units of formula (II):

wherein:

Pi comprises a photoinitiator moiety;

R comprises a hydrogen atom or an optionally substituted C 1 -C 6 alkyl or an optionally substituted C 6 -C 10 aryl;

Z comprises a linker moiety comprising a single bond, optionally substituted C 1 -C 12 alkylene, optionally substituted C 1 -C 12 alkenylene, —O—, —S—, —NR a —, —CO—NR a —, optionally substituted heterocyclyl, optionally substituted arylene, optionally substituted —[O—(C 1 -C 12 alkylene)] n− optionally substituted —[S—(C 1 -C 12 alkylene)] n− and combinations thereof, wherein n is an integer from 1-20, and wherein R a comprises H or an optionally substituted C 1 -C 6 alkyl.

2. The polymer according to claim 1 , wherein Z comprises a single bond, C 1 -C 12 alkylene, C 1 -C 12 alkenylene, —O—, —S—, —NR a —, or —[O—(C 1 -C 12 alkylene)] n , wherein R a comprises H or an optionally substituted C 1 -C 12 alkyl and n is an integer from 1-20.

3. The polymer according to claim 1 , wherein Z comprises a single bond, C 1 -C 12 alkylene, —O—(C 1 -C 12 alkylene)-, C 1 -C 6 alkylene, or —O—(C 1 -C 6 alkylene)-.

4. The polymer according to claim 1 , wherein Pi comprises a Norrish type-I photoinitiator moiety.

5. The polymer according to claim 1 , wherein Pi comprises benzoin ethers, 1-phenyl-2-hydroxy-2-alkyl ketones, 1-phenyl-2-amino-2-alkyl ketones, dibenzosuberones, benzils, benzil ketals, acetophenones, α-alkoxy-acetophenones, α,α-dialkoxy-acetophenones, α-hydroxy-α-alkyl-phenones, α-hydroxy-α,α-dialkyl-phenones, alkyl phenylglyoxylates, camphorquinones, acyl-phosphine oxides, or phenyl ketocoumarins.

6. The polymer according to claim 1 , wherein Pi comprises a photoinitiator comprising acetophenones, α-alkoxy-acetophenones, α,α-dialkoxy-acetophenones, α-hydroxy-α-alkyl-phenones, α-hydroxy-α,α-dialkyl-phenones, or alkyl phenylglyoxylates.

7. A polymer according to claim 1 , wherein Pi comprises a Norrish Type-I photoinitiator moiety comprising formula (V):

—P h —(X) m   (V)

wherein Ph comprises an optionally-substituted phenyl ring;

wherein m is an integer of 1-5, such that m X moieties may be present at any position on Ph; and

wherein X comprises one of:

wherein each Rx comprises H or an optionally substituted C 1 -C 6 alkyl.

8. The polymer according to claim 7 , wherein the X is present at the para-position on the Ph.

9. The polymer according to claim 7 , wherein m is 1 or 2.

10. The polymer according to claim 1 , wherein the one or more units (I) and (II) comprise formulae (Ia) and (IIa):

11. The polymer according to claim 1 , further comprising of one or more units with formula (III) and/or one or more units with formula (IV):

12. The polymer according to claim 11 , further comprising of one or more units with formula (I), one or more units with formula (II), one or more units with formula (III) and one or more units with formula (IV).

13. The polymer according to claim 12 , wherein the ratio between the one or more units with formula (I): one or more units with formula (II): one or more units with formula (III): and one or more units with formula (IV) (I:II:III:IV) is expressed as a:b:c:d, wherein each of a, b, c and d are each independently between 0 and 1, wherein a +b+c +d=1.

14. The polymer according to claim 12 , wherein a is between 0.01 and 0.1.

15. The polymer according to claim 12 , wherein b is between 0.01 and 0.1.

16. The polymer according to claim 1 , further comprising at least one additional repeat unit(s), the additional repeat unit(s) comprising an optionally-substituted C 2 -alkylene.

17. The polymer according to claim 16 , wherein the C 2 -alkylene is mono-substituted with a C 1 -C 6 alkyl ether or an aryl.

18. The polymer according to claim 11 , further comprising at least one additional repeat unit(s), the additional repeat unit(s) comprising an optionally-substituted C 2 -alkylene.

19. The polymer according to claim 18 , wherein the C 2 -alkylene is mono-substituted with a C 1 -C 6 alkyl ether or an aryl.

20. The polymer according to claim 12 , further comprising at least one additional repeat unit(s), the additional repeat unit(s) comprising an optionally-substituted C 2 -alkylene.

21. The polymer according to claim 20 , wherein the C 2 -alkylene is mono-substituted with a C 1 -C 6 alkyl ether or an aryl.

22. The polymer according to claim 10 , further comprising one or more units with formula (Ia), one or more units with formula (IIa), one or more units with formula (III) and/or one or more units with formula (IV):

23. The polymer according to claim 22 , wherein the ratio between the one or more units with formula (Ia): one or more units with formula (IIa): one or more units with formula (III): and one or more units with formula (IV) (Ia:IIa:III:IV) is expressed as a:b:c:d, wherein each of a, b, c and d are independently between 0 and 1, provided that a and b are not both 0, and wherein a+b+c+d=1.

24. The polymer according to claim 22 , wherein a is between 0.01 and 0.1.

25. The polymer according to claim 22 , wherein b is between 0.01 and 0.1.

26. The polymer according to claim 22 , further comprising at least one additional repeat unit(s), the additional repeat unit(s) comprising an optionally-substituted C 2 -alkylene.

27. The polymer according to claim 26 , wherein the C 2 -alkylene is mono-substituted with a C 1 -C 6 alkyl ether or an aryl.

28. A method for synthesizing a polymer according to claim 1 , the method comprising the steps of: reacting an amine photoinitiator comprising formula (X)

H—N(R)—Z-Pi  (X)

wherein Z, R and Pi are as previously defined;

with a polymer comprising a maleic anhydride functionality;

such that a succinimide and amide moiety is formed between the maleic anhydride moiety and the primary amine so as to provide the polymer comprising pendant photoinitiator moieties, wherein the photoinitiator moieties are bound to the polymer via the N-atom of the succinimide.