221554-45-6 Pentanoic acid, 3-hydroxy-, (3R)-, polymer with (3R)-3-hydroxybutanoic acid, ester with 1,2-ethanediol (2:1), block, polymer with 1,6-diisocyanato-2,2,4(or 2,4,4)-trimethylhexane and 1,4-dioxane-2,5-dione block polymer with 2-oxepanone ester with 1,2-etha