During the polymerization of {TAIL ~ the monomers} required to form the polyethylene terephthalate, {HEAD ~ a quantity} of polyethylene glycol is copolymerized therewith to form a polymer which exhibits a substantial intrinsic viscosity  
During the polymerization of { TAIL ~ the monomers } required to form the polyethylene terephthalate , { HEAD ~ a quantity } of polyethylene glycol is copolymerized therewith to form a polymer which exhibits a substantial intrinsic viscosity
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH