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