Styryl-POSS Polymers, Copolymers, and Nanocomposites

Haddad and Lichtenhan synthesized the styryl-substituted POSS, R7(SigOi2)(CH2CH2C6H4CH= CH2), where R = either cyclohexyl, 2a, or 

Poly(4-methylstyrene) has substantially lower values of Tg (116°C) and Tj (388°C) than either of the styryl-POSS homopolymers, 3a and 3b. The 4-methylstyrene copolymers 8a and 8b of the styryl-POSS monomers 2a and 2b, which contain only 1 mol % of the POSS monomer, exhibited lower values of Tg and (8a, Tg = 112°C and r = 378°C 8b, rg=113°C and r = 383°C) than those of poly(4-methyl styrene). However, as the mole percent of POSS increased to 9, the copolymers 7a and 7b exhibited higher values of Tg and Tj (7a, Tg= 132°C and r = 402°C 7b, Tg= 127°C and = 399°C), which are higher than those of pure poly(4-methyl-styrene). The Tg and T values increase with an increase in the mole percent of POSS. =  

The other copolymers of styryl-POSS and its blend with PS (nanocomposifes) have been reported. Haddad et al. described the preparation of three styrene copolymers with cyclohexyl-, cyclopentyl-, and isobutyl-substituted monofunctional styryl-POSS monomers (at 30 wt % or approximately 4mol % loadings) using free-radical bulk polymerization. The storage moduli, E, of these three POSS copolymers and polystyrene (PS) at room temperature are similar and typical for glassy polymers. However, at 30°C above the glass-transition temperature, the moduli of 

Two copolymers of poly(j9-acetoxystyrene-co-isobutylstyryl-POSS) (P(AS-co-POSS)) and poly(vinylpyrrolidone-co-isobutylstyryl-POSS) (P(VP-co-POSS)) were synthesized (Fig. 7). The P(AS-co-POSS) copolymers, with 0.98-4.03 mol % POSS, exhibited lower Tg values than that of pure PAS. However, the Tg value 

IR spectroscopy was appUed to study interaction among these copolymers. The Tg values of these copolymers were found to depend on three factors (1) the inert role of POSS as a diluent that reduces the self-association dipole-dipole interactions of the parent polymer molecules (a negative confribution), (2) the dipole-dipole interactions between the POSS s siloxane cage and the polar carbonyl 

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