The remaining new band at 1380 [cm.sup.-1] is assignable to the symmetric bending mode of acetoxyl methyl group linked to the Si element, Si-O-CO-C[H.sub.3] (13).
Correspondingly, the spectrum also showed a marked growth in the peak at 1380 [cm.sup.-1], attributed to the formation of acetoxyl methyl group, while the prominence of the amide-related peaks remained unchanged.
The two remaining reactions occurred between Ce acetate and the amine or silanol groups within APST, leading to the formation of the acetamide and acetoxyl methyl moieties as the end reaction products in the polypropylsiloxane network; meanwhile, the Ce hydroxide derivative was introduced into this polymer.
In other words, the remaining APST monomers might have reacted with the Ce acetate to form the propylsilane structure containing the acetamide and acetoxyl methyl groups, which possess greater thermal stability than does APST.
The APST remnants favorably reacted with Ce acetate to form water-insoluble acetoxyl methyl- and acetamide-linked propylsilane compounds.
(16) Relating this finding to the chemical structure of PAAMPS illustrated earlier, it is possible to assume that among these carbon-associated bonds, three bonds, C-H, C-N, and C=O, belong to the acetamide moiety, and that three bonds, C-H, C=O, and -COO, are associated with the acetoxyl methyl moiety linked to Si.
Lemieux also continued studies of the anomeric effect, a term which he introduced in 1958 to describe the effect responsible for an electronegative substituent such as chlorine or
acetoxyl at an anomeric centre preferring an axial to an equatorial orientation.