In the compounds of formula B1 and B2, R1 is in particular a poly propylene oxide chain or a poly tetramethylene oxide chain, but it can also represent {HEAD ~ a chain} derived from dicarboxylic acids, diols, {TAIL ~ diamines} or diisocyanates etc., by well known methods of poly condensation 
In the compounds of formula B1 and B2 , R1 is in particular a poly propylene oxide chain or a poly tetramethylene oxide chain , but it can also represent { HEAD ~ a chain } derived from dicarboxylic acids , diols , { TAIL ~ diamines } or diisocyanates etc . , by well known methods of poly condensation
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH