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US5264538A Cyclic poly(aryl ether) oligomers 失效
环状聚(芳基醚)低聚物

Cyclic poly(aryl ether) oligomers
摘要:
Cyclic poly(aryl ether) oligomers and mixtures thereof, and methods for the preparation thereof in a highly dilute reaction medium under reaction conditions favorable for ring closure at low degrees of polymerization. These oligomers are represented by the general formula ##STR1## where each Y is divalent oxygen or divalent sulfur, each Ar is an aromatic diradical which comprises one or more C.sub.6 to C.sub.20 arylene groups and has at least one electron withdrawing group attached to an aromatic ring, and n is an integer from 1 to about 20 with the proviso that for integer values of n equal to 1 or 2 all linkages between independent aromatic rings comprise at least one atom.
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