 from {HEAD ~ about 75 mole percent} to about 90 mole percent of {TAIL ~ acrylonitrile}; and 
from { HEAD ~ about 75 mole percent } to about 90 mole percent of { TAIL ~ acrylonitrile } ; and
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH