{HEAD ~ Plastics} which cure in a series of steps having {TAIL ~ urethane}, urea, siloxane and acrylate groups 
having
{ HEAD ~ Plastics } which cure in a series of steps having { TAIL ~ urethane } , urea , siloxane and acrylate groups
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH