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