{HEAD ~ iii) chain extending agents} and crosslinking agents having an average molecular weight of 62 to 500 and having {TAIL ~ an average functionality} of 2 to 4 and 
{ HEAD ~ iii ) chain extending agents } and crosslinking agents having an average molecular weight of 62 to 500 and having { TAIL ~ an average functionality } of 2 to 4 and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH