what is rubber process oil effect on polymers ?

Rubber  processing  oils  (RPOs)  are  organic substances which are usually added  to  polymers  to  improve  the  process ability  of  such  polymers.  Further  advantages  of  the  aromatic rubber process oil are  increments  in  desirable  polymer  properties, such as softness, elongation and  low-temperature  flexibility.  Moreover,  the  RPO  provide  the  rubber  compounds  with  lowered  intermolecular forces, and so a lower glass  transition  temperature