prov:value
| - Specific examples of preferred divalent hydrocarbon groups include alkylene groups having 1 to 10 carbon atoms such as methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, octamethylene, nonamethylene, dexamethylene and dimethylmethylene; arylene groups having 6 to 12 carbon atoms such as phenylene, naphthylene, diphenylene, groups of the formula ##STR9## wherein Z is
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