Ch. Weidner et Te. Long, SYNTHESIS AND CHARACTERIZATION OF 3-ARYL-2-(POLYSTYRYL)CYCLOPROPENONES VIA CYCLOPROPENIUM ION SUBSTITUTION ON POLYSTYRENE, Journal of polymer science. Part A, Polymer chemistry, 33(1), 1995, pp. 1-6
Electrophilic substitution of cyclopropenium ions on aromatic polymers
offers a unique opportunity to introduce polar functionality in a con
trolled manner to conventional, nonpolar polymers. Phenylcyclopropenon
e substituted polystyrene with predictable chemical composition and na
rrow molecular weight distribution were prepared. Size exclusion chrom
atography (SEC) analysis demonstrated the absence of branching or cros
slinking in these functionalized polystyrenes during electrophilic sub
stitution of the parent homopolymer. C-13-NMR confirmed that the degre
e of phenylcyclopropenone substitution was both highly efficient and p
redictable over a broad compositional range. The glass transition temp
erature (T(g)) of the polymers was found to vary linearly with mole %
phenylcyclopropenone substitution of the polystyrene. Thermal gravimet
ric analysis (TGA) indicated that thermal decarbonylation of the appen
ded cyclopropenones occurred at approximately 180-degrees-C. Weight lo
ss vs. temperature profiles correlated reasonably well with levels of
substitution based on C-13-NMR analysis, confirming that decarbonylati
on of the calculated cyclopropenone substituents was the predominant t
hermal decomposition pathway. (C) 1995 John Wiley & Sons, Inc.