ELECTRICAL COMPONENT AND METHOD

1 . A subsea electrical connector or electrical cable, comprising:

a conductor,

an insulator coaxial with the conductor; and

at least one of a volumetric compensating diaphragm located radially outwardly of the insulator, or a termination boot;

wherein the diaphragm or termination boot comprises a compound layer, the compound layer comprising a graphene nano-platelet additive incorporated into a cross-linked polymer matrix to produce a polymer composite.

2 . The subsea electrical connector or electrical cable according to claim 1 ,

wherein the subsea electrical connector or electrical cable comprises both a termination boot and a volumetric compensating diaphragm.

3 . The subsea electrical connector or electrical cable according to claim 1 ,

wherein a proportion of graphene nano-platelet additive expressed in parts per hundred rubber (PHR) is between 0.1 and 5.0.

4 . The subsea electrical connector or electrical cable according to claim 3 ,

wherein the proportion of graphene nano-platelet additive PHR is between 0.1 and 1.0.

5 . The subsea electrical connector or electrical cable according to claim 1 ,

wherein the compound layer is in physical contact with at least part of the insulator.

6 . The subsea electrical connector or electrical cable according to claim 4 ,

wherein the compound layer forms a sealed chamber containing an insulating liquid.

7 . The subsea electrical connector or electrical cable according to claim 4 ,

wherein the cross-linked polymer matrix comprises an elastomer.

8 . The subsea electrical connector or electrical cable according to claim 7 ,

wherein the elastomer comprises one of styrene-butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, chloroprene rubber, ethylene propylene diene rubber, fluoro elastomers, perfluoro elastomers, silicone rubber, or fluoro silicone rubber.

9 . A method of manufacturing a component of a subsea electrical connector, or electrical cable according to claim 1 , the component comprising a volumetric compensating diaphragm, or a termination boot, the method comprising:

creating a compound layer of the component by determining proportions of graphene nano-platelets and a cross-linked polymer matrix for the component;

incorporating the graphene nano-platelets into the cross-linked polymer matrix in the determined proportions to produce a polymer composite; and

forming the component from the polymer composite.

10 . The method according to claim 9 , further comprising:

aligning the graphene nano-platelets in the same direction, perpendicular to a diffusion path of water through the component.

11 . The method according to claim 9 , further comprising:

moulding an elastomer through a transfer moulding process by transferring the polymer composite into a mould cavity under pressure through a small orifice to induces a high shear rate on the compound.

12 . The method according to claim 9 , further comprising:

providing a cure system in the polymer composite and applying thermal treatment to the polymer composite, causing the polymer to cross-link, to form the component.

13 . The method according to claim 9 ,

wherein a proportion of graphene nano-platelet additive is between 0.1 PHR and 5.0 PHR.

14 . The method according to claim 13 ,

wherein the proportion of graphene nano-platelet additive is between 0.1 PHR and 1.0 PHR.

15 . The method according to claim 9 ,

wherein a desired maximum leakage rate is chosen and a corresponding proportion of graphene nano platelets is determined for the polymer matrix by extracting values from a store.

16 . A method of manufacturing a subsea electrical connector, or electrical cable, the method comprising:

manufacturing a component of a subsea electrical connector or electrical cable by a method according to claim 9 ; and

coupling the component to an insulating layer of the subsea electrical connector, or electrical cable.

17 . A method of manufacturing a subsea electrical connector, or electrical cable, the method comprising:

manufacturing a component of a subsea electrical connector or electrical cable by a method according to claim 9 ,

wherein the forming comprises over-moulding the polymer composite onto an insulating layer, or co-extruding the polymer composite with the insulating layer of the subsea electrical connector or electrical cable.

18 . The subsea electrical connector or electrical cable according to claim 3 ,

wherein the proportion of graphene nano-platelet additive PHR is between 0.1 and 0.5

19 . The subsea electrical connector or electrical cable according to claim 3 ,

wherein the proportion of graphene nano-platelet additive PHR is between 0.5 and 1.0.

20 . The method according to claim 13 ,

wherein the proportion of graphene nano-platelet additive is between 0.2 PHR and 0.5 PHR

21 . The method according to claim 13 ,

wherein the proportion of graphene nano-platelet additive is between 0.5 PHR and 1.0 PHR.