| 摘要 |
<p>Novel polymers have repeating units of formula: (where arrows represent an isomer, Ar is tetravalent aromatic radical having 2 gps. of 2 valencies in ortho and peri posns. forming simple rings or fused rings joined by one of the following: -O-; -S-; -SO-; -CO-; -C(O)O - or -R1N-C(O)-NR1- and Ar' is a divalent aromatic radical). These polymers are used to make high temp. resistant adhesives, foams, moulded objects etc. but are pref. used in mfg. material composites.</p> |
