Yf. Wang et al., NOVEL MACROCYCLIC ARYL ETHER OLIGOMERS CONTAINING A DIPHENYLACETYLENEMOIETY - SYNTHESIS, CHARACTERIZATION AND RING-OPENING POLYMERIZATION, Polymer, 38(2), 1997, pp. 469-482
An efficient synthetic route to a range of macrocyclic aryl ether keto
ne and sulfone oligomers containing a cross-linkable diphenylacetylene
moiety in the backbone is described. This new class of macrocyclic ol
igomers, obtained in excellent yield, is prepared by an aromatic nucle
ophilic substitution reaction from the potassium salt of bis(3-hydroxy
phenyl)acetylene and activated difluoro-monomers. Detailed structural
characterization of these novel oligomers by the combination of n.m.r.
and matrix assisted laser desorption and ionization-time of flight-ma
ss spectroscopy (MALDI-TOF-MS) confirms their cyclic nature; and the c
ompositions of these macrocyclic oligomers are provided by g.p.c. and
reverse-phase gradient h.p.l.c. analyses. MALDI-TOF-MS is a unique too
l for the determination and the proof of the cyclic nature of random c
o-cyclic oligomers, and also provides answers to the possible combinat
ions of monomer units in the cyclic olgiomeric components for the rand
om co-cyclic oligomers. All macrocyclic oligomers are semicrystalline
with T-m varying from 267 to 370 degrees C and when the oligomers are
heated an exothermic reaction, resulting from reaction of the acetylen
e units, occurs in the range of 340-470 degrees C and the macrocyclics
undergo a cross-linking reaction. Polymerization of the lower melting
macrocyclic oligomers at 280-300 degrees C, in the presence of a nucl
eophilic initiator, led to the formation of high molecular weight inso
luble materials with limited cross-linking reactions taking place. The
resulting polymers can be further cross-linked at 340 degrees C with
a T-g increase up to 100 degrees C or complete disappearance of T(g)s.
Copyright (C) 1996 Elsevier Science Ltd.