Process for making ethylene-based polymers using hydrocarbon initiators

1. A process for making an ethylene-based polymer, the process comprising the step of contacting at polymerization conditions ethylene and, optionally, one or more alpha-olefin comonomers, with at least one carbon-carbon (C—C) hydrocarbyl, free-radical initiator of any of Structures IV-VIII:

3,4-diethyl-3,4-diphenyl hexane (Structure IV)

2,7-dimethyl-4,5diethyl-4,5-diphenyl octane (DBuDPH) (Structure V)

3,4-dibenzyl-3,4-ditolyl hexane (DBnDTH) (Structure VI)

3,4-diethyl-3,4-di(dimethylphenyl) hexane (Structure VII)

and, 3,4-dibenzyl-3,4-diphenyl hexane (Structure VIII)

and the polymerization conditions include a polymerization temperature of 210° C-300°C.

2. The process of claim 1 in which the C—C hydrocarbyl, free-radical initiator is present in an amount greater than, or equal to, 0.001 grams per kilogram (g/kg) of the ethylene fed to the polymerization reaction.

3. The process of claim 1 in which the C—C hydrocarbyl, free-radical initiator has a decomposition temperature of greater than or equal to (≧) 125° C. based on a DSC measurement.

4. The process of claim 1 in which two or more C—C hydrocarbyl, free-radical initiators are contacted with ethylene and, optionally, one or more alpha-olefin comonomers.

5. A process for making an ethylene-based polymer, the process comprising the step of contacting ethylene and, optionally, one or more comonomers, with at least one carbon-carbon (C—C) hydrocarbyl, free-radical initiator with a DSC decomposition temperature less than, or equal to, 145° C. and of Structure I:

wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each, independently, hydrogen or a hydrocarbyl group and wherein, optionally, two or more R groups (R 1 , R 2 , R 3 , R 4 , R 5 and R 6 ) form a ring structure, with the proviso that at least one of R 2 and R 5 , and at least one of R 3 and R 6 is an alkaryl group of at least seven carbon atoms.

6. The process of claim 5 in which a comonomer is present and the comonomer is at least one of an alpha-olefin, an acrylate or a methacrylate.

7. The process of claim 6 in which the initiator is selected from the group consisting of 3,4-dibenzyl-3,4-ditolyl hexane (Structure VI)

and, 3,4-dibenzyl-3,4-diphenyl hexane (Structure VIII)

8. The process of claim 6 in which the ethylene and, optionally, one or more comonomers, are contacted with at least one carbon-carbon (C—C) hydrocarbyl, free-radical initiator in the absence of a peroxide or other form of oxygen.

9. The process of claim 6 in which the ethylene and, optionally, one or more comonomers, are contacted with at least one carbon-carbon (C—C) hydrocarbyl, free-radical initiator in the presence of a peroxide or other form of oxygen.

10. The process of claim 6 in which the acrylate is 2-methylhexyl acrylate.

11. An ethylene-based polymer made by the process of claim 5 .

12. The ethylene-based polymer of claim 11 made in the absence of oxygen and having the following properties: (1) a carbonyl ratio of less than (<) 0.02, and (2) a dissipation factor less than or equal to (≦) 1.49×10 −4 radian at 2.47 GHz, and (3) an oxygen content of less than 50 parts per million (ppm) by weight.

13. The ethylene-based polymer of claim 12 in which the polymer is a low density polyethylene (LDPE).

14. The ethylene-based polymer of claim 12 in which the carbonyl ratio is less than (<) 0.01.