xakis[p-(hydroxymethyl)phenoxy]cyclotriphosphazene was prepared by the
reaction of hexachlorocyclotriphosphazene with the sodium salt of 4-h
ydroxybenzaldehyde and subsequent reduction of aldehyde groups to alco
hol groups by using sodium borohydride. The bromination reaction was c
arried out by using hydrobromic acid-sulfuric acid to give exakis[p-(b
romomethyl)phenoxy]cyclotriphosphazene. This compound was employed in
initiating polymerization of 2-methyl-2-oxazoline to produce six-armed
, star-branched polymers. Monofunctional initiator, N3P3(OC6H5)5(OC6H4
-p-CH2Br), was also prepared and used for initiating the polymerizatio
n of 2-methyl-2-oxazoline to result in linear polymers. Molecular weig
hts and DP's per an arm of the polymers were determined by gel permeat
ion chromatography and H-1 NMR, respectively. The molecular weight of
the linear polymer measured by GPC was much higher than that of the st
ar-branched polymer when their molecular weights determined by H-1 NMR
were nearly same. The linear polymer (DP = 31) with a bulky hydrophob
ic head and a hydrophilic chain exhibited nonionic surfactant behavior
, forming micelles above a polymer concentration of about 0.1% by weig
ht. The star-branched polymers had a hydrophobic core and hydrophilic
branches. The surface tension of the aqueous solution of the star-bran
ched polymer (DP = 13.4 per branch) decreased very slowly as polymer c
oncentration increased, and any evidence for forming micelles was not
observed. N-Acetyl groups of star-branched polymers were removed by hy
drolysis under acidic conditions to give the polymers with N-protonate
d poly(ethylenimine) branches.