Di-cumyl peroxide crosslinking of UHMWPE

1. A peroxide cross-linked and high temperature melted polymeric material fabricated from peroxide crosslinked ultra-high molecular weight polyethylene containing vitamin-E, wherein ultra-high molecular weight polyethylene is first blended with di-cumyl peroxide and vitamin E to form a blend, wherein said blend is compression molded to obtain a crosslinked and consolidated article and cooled to about room temperature, wherein the crosslinked and consolidated article is then subjected to a high temperature melting (HTM) cycle in a reduced oxygen environment to produce a peroxide cross-linked and high temperature melted polymeric material, wherein the peroxide cross-linked and high temperature melted polymeric material has an acetophenone (ACP) index less than 0.03 and an elongation at break (EAB) less than 400%,

wherein the high temperature melting cycle comprises

heating the crosslinked and consolidated article above 250° C. for at least 50 hours and less than 70 hours, wherein during the heating the crosslinked and consolidated article is heated at 295±5° C. for a duration that is not longer than 9 hours.

2. The peroxide cross-linked and high temperature melted polymeric material of claim 1 , wherein the peroxide cross-linked and high temperature melted polymeric material is fabricated into an insert and the insert is further machined into a medical implant.

3. The medical implant of claim 2 is cleaned, packaged, and gamma sterilized.

4. The peroxide cross-linked and high temperature melted polymeric material of claim 1 , wherein the HTM cycle comprises steps of:

heating said crosslinked and consolidated article to a target temperature of 275° C. and holding for a target duration of 4 h;

heating said crosslinked and consolidated article to a target temperature of 295° C. and holding for a target duration of 8 h;

cooling said crosslinked and consolidated article to a target temperature of 275° C. and holding for a target duration of 43 h;

cooling said crosslinked and consolidated article to a target temperature of 130° C. and holding for a target duration of 5 h;

cooling said crosslinked and consolidated article to a target temperature of 115° C. and holding for a target duration of 5 h;

cooling said crosslinked and consolidated article to a target temperature of 105° C. and holding for a target duration of 5 h;

cooling said crosslinked and consolidated article to a target temperature of 40° C. and holding for a target duration of 2 h; and

wherein a temperature of any one of the steps can be 5° C. above or below the target temperatures and a holding duration of any one of the steps can be half hour longer or shorter of said target durations.

5. The HTM cycle of claim 1 , wherein the heating temperatures and durations depend on the size of the crosslinked and consolidated article.

6. The HTM cycle of claim 4 , wherein the heating temperatures and durations depend on the size of the crosslinked and consolidated article.

7. The crosslinked and consolidated article of claim 5 , wherein the crosslinked and consolidated article has a height less than 3 inches.

8. The crosslinked and consolidated article of claim 6 , wherein the crosslinked and consolidated article has a height less than 3 inches.

9. The peroxide cross-linked and high temperature melted polymeric material of claim 1 , wherein the peroxide crosslinked and consolidated article is heated at 295±5° C. for a duration of at least 8 hours.

10. A wear resistant medical implant fabricated from peroxide crosslinked ultra-high molecular weight polyethylene containing vitamin-E, wherein ultra-high molecular weight polyethylene is first blended with di-cumyl peroxide and vitamin E to form a blend, wherein the blend is compression molded to obtain a crosslinked and consolidated preform and cooled to about room temperature, wherein the crosslinked and consolidated preform is subjected to a high temperature melting (HTM) cycle in a reduced oxygen environment to produce a peroxide cross-linked and high temperature melted polymeric preform, wherein the peroxide cross-linked and high temperature melted polymeric preform has an acetophenone (ACP) index less than 0.03 and an elongation at break (EAB) less than 400%, wherein the peroxide cross-linked and high temperature melted polymeric preform is machined into a medical implant,

wherein the high temperature melting cycle comprises heating the crosslinked and consolidated preform above 250° C. for at least 50 hours and less than 70 hours, wherein during the heating the crosslinked and consolidated preform is heated at 295±5° C. for a duration that is not longer than 9 hours.

11. The wear resistant medical implant of claim 10 , wherein the HTM cycle comprises steps of:

heating said crosslinked and consolidated preform to a target temperature of 275° C. and holding for a target duration of 4 h;

heating said crosslinked and consolidated preform to a target temperature of 295° C. and holding for a target duration of 8 h;

cooling said crosslinked and consolidated preform to a target temperature of 275° C. and holding for a target duration of 43 h;

cooling said crosslinked and consolidated preform to a target temperature of 130° C. and holding for a target duration of 5 h;

cooling said crosslinked and consolidated preform to a target temperature of 115° C. and holding for a target duration of 5 h;

cooling said crosslinked and consolidated preform to a target temperature of 105° C. and holding for a target duration of 5 h;

cooling said crosslinked and consolidated preform to a target temperature of 40° C. and holding for a target duration of 2 h; and

wherein a temperature of any one of the steps can be 5° C. above or below the target temperatures and a holding duration of any one of the steps can be half hour longer or shorter of said target durations.

12. The HTM cycle of claim 10 , wherein the heating temperatures and durations depend on the size of the crosslinked and consolidated preform.

13. The HTM cycle of claim 11 , wherein the heating temperatures and durations depend on the size of the crosslinked and consolidated preform.

14. The crosslinked and consolidated preform of claim 12 , wherein the crosslinked and consolidated preform has a height less than 3 inches.

15. The crosslinked and consolidated preform of claim 13 , wherein the crosslinked and consolidated preform has a height less than 3 inches.

16. The wear resistant medical implant of claim 10 , wherein the peroxide crosslinked and consolidated preform is heated at 295±5° C. for a duration of at least 8 hours.

17. The wear resistant medical implant of claim 10 , wherein the wear resistant medical implant is cleaned, packaged, and gamma sterilized.

18. The wear resistant medical implant of claim 10 , wherein the wear resistant medical implant is a tibial knee insert.