Method of crosslinking polyolefins

Abstract

A method of forming an engineering component comprising the steps of: subjecting a workpiece or blank formed from polyolefin to gamma radiation at a total dose sufficient to cause a predetermined degree of crosslinking, wherein the total dose is applied at a dosage rate of less than 5 kGy/hour to cause crosslinking of the polymer and forming an engineering component from the crosslinked material.

1 . A method of forming an engineering component comprising the steps of: 
 subjecting a workpiece or blank formed from polyolefin to gamma radiation at a total dose sufficient to cause a predetermined degree of crosslinking, wherein the total dose is applied at a dosage rate of less than 5 kGy/hour to cause crosslinking of the polymer and forming an engineering component from the crosslinked material.    
     
     
         2 . A method as claimed in  claim 1  wherein the dosage rate is less than 3 kGy/hour.  
     
     
         3 . A method as claimed in  claim 2  wherein the dosage rate is less than 1.5 kGy/hour.  
     
     
         4 . A method as claimed in a preceding claim wherein the polyolefin is an unblended homopolymer.  
     
     
         5 . A method as claimed in  claim 4  wherein the polyolefin is polyethylene.  
     
     
         6 . A method as claimed in  claim 5  wherein the polymer is ultra high molecular weight polyethylene.  
     
     
         7 . A method as claimed in any preceding claim wherein the crystallinity of the crosslinked polyolefin is at least 40%.  
     
     
         8 . An engineering component comprising polyolefin crosslinked in accordance with the method of any preceding claim.  
     
     
         9 . A surgical implant or prostheses comprising a polyolefin crosslinked in accordance with the method of any of claims  1 - 7 .