Process for modifying ethylene-based polymers and copolymers

1. Process for functionalising an ethylene-based (co)polymer comprising the step of contacting an ethylene-based (co)polymer at a temperature in the range 100-250° C. with an azide of formula (I)

wherein Y is either

m is 0 or 1, n is 0 or 1, n+m=1 or 2, and X is a linear or branched, aliphatic or aromatic hydrocarbon moiety with 1-12 carbon atoms, optionally containing heteroatoms.

2. Process according to claim 1 wherein the ethylene based (co)polymer is LDPE.

3. Process according to claim 1 wherein the ethylene-based (co)polymer is EPM.

4. Process according to claim 1 wherein the azide is selected from 4-(3-methyl-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)benzene sulfonyl azide (also called citraconimide benzenesulfonylazide) and 2-(3-methyl-2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl carbonazidate (also called citraconimide-C2-azidoformate).

5. Process according to claim 1 wherein the ethylene-based (co)polymer and the azide are contacted at a temperature in the range 140-230° C.

6. Process according to claim 1 wherein the azide is mixed with the ethylene-based (co)polymer in an amount of 0.1-5 phr.

7. Process for modifying an ethylene-based (co)polymer—comprising the steps of:

preparing a functionalised ethylene-based (co)polymer according to the process of claim 1

contacting the functionalised ethylene-based (co)polymer with an organic peroxide to form a polymer/peroxide mixture, and

heating said polymer/peroxide mixture at a temperature in the range 140-300° C.

8. Process according to claim 7 wherein the polymer/peroxide mixture is shaped prior to heating.

9. Process according to claim 7 wherein the polymer/peroxide mixture is shaped by extrusion.

10. Process according to claim 7 wherein the organic peroxide is a dialkyl peroxide or a trioxepane.

11. Process according to claim 7 wherein the organic peroxide is selected from the group consisting of 3,3,5,7,7-pentamethyl-1,2,4trioxepane, 2,5-dimethyl-2,5-di(tertbutylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tertbutylperoxy)hexane, di(tert-butylperoxyisopropyl)benzene, dicumyl peroxide, and tert-butyl cumyl peroxide.

12. Functionalised ethylene-based (co)polymer obtainable by the process according to claim 1 .

13. Modified ethylene-based (co)polymer obtainable by the process according to claim 7 .

14. A process for making power cables comprising an electrical connector surrounded by one or more layers of the functionalised ethylene-based (co)polymer of claim 1 .

15. A power cable comprising one or more layers of the modified ethylene-based (co)polymer of claim 1 .