What is the difference between PVC and xlpe cable?

 In the context of electrical cables, PVC and XLPE are two materials used as insulation. XLPE has got more capacity to hold on incase of high temperature. XLPE will not deteriorate it's insulating property until it reaches 90 degree celsius. It will not suddenly lose it's insulating property if the themperature jumps just above 90. But the overall life of the cable will be reduced. PVC can withstand temperatures only upto 70 degree Celsius. 

PVC is cheaper than XPLE, hence it's find it's place in market today. 
PVC is a thermo plastic where as XLPE is thermosetting plastic. 
PVC - Poly Vinyl chloride 
XLPE - Cross linked Poly Ethylene