A polymer based on a dicarboxylic acid and a diamine is prepared by {TAIL ~ polycondensation} in {HEAD ~ an extruder}, by 
A polymer based on a dicarboxylic acid and a diamine is prepared by { TAIL ~ polycondensation } in { HEAD ~ an extruder } , by
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH