Hy. Jiang et al., Synthesis, structure and ring-opening polymerization of phenolphthalein macrocyclic polyarylates, MACRO CH P, 201(17), 2000, pp. 2385-2393
Phenolphthalein based polyarylate macrocyclic oligomers were selectively sy
nthesized by an interfacial polycondensation reaction of o-phthaloyl dichlo
ride with phenolphthalein. The high selectivity benefits from the role of p
henolphthalein as a color indicator, an efficient phase transfer catalyst,
acid a preferred conformation of the starting materials as indicated by ana
lyzing a single-crystal X-ray structure of an analogous macrocycle. The mel
t ROP of phenolphthalein polyarylate cyclic dimer was studied using nucleop
hilic initiators, The molecular weight of the resulting polymers builds up
very rapidly at the very early stage of polymerization but decreases with t
ime. During the ROP of cyclic dimer, analogous macrocycles with higher degr
ee of polymerization (n greater than or equal to 3) and linear oligomers we
re produced by backbiting reaction especially at later stage of polymerizat
ion. Conversion of cyclic dimer is very fast at the earlier stage of polyme
rization and then increases slowly with time as analyzed by gel permeation
chromatography. However, the total amount of cyclic oligomers in the ROP sy
stem increases with time at the later stage of polymerization because of th
e formation of larger macrocycles. The resulting polymers are amorphous. Gl
ass transition temperatures (T(g)s) of these polymers are influenced by the
polymerization time, type of initiator, and initiator concentration.