Keele Research Repository

This work has been divided into two sections:
SECTION A (Chapters 1-5)
This section is concerned with the preparation and cationic polymerization of various ketene acetals CH2 :C(OR1)OR2. Four ketene acetals have been synthesized (two of which are new compounds) and their polymerizabi1ity has been investigated under homogeneous and heterogeneous conditions, in bulk and in solution, between ca. +50◦ and -100◦. The monomers studied comprise (KA1) R1 =R2 = C2H4OMe; (KA2) R1=R2 = Et; (KA3) R1=Me, R =Et; (KA4) R1=Et, R2=i-Pr.
Most of the reaction products formed in solution were viscous pale yellow fluids or sticky red solids; whereas those formed in bulk with solid, sparsely soluble initiators were white waxes or powders. For all systems for which solubility of product permitted DP determinations, the highest DPs (ca. 20) were found from bulk polymerization with solid CdCl2. With a wide range of soluble initiators in different solvents over a wide range of concentrations DPs greater than about 8 were exceptional.
It is suggested that there are at least four chain breaking reactions involving the growing dialkoxycarbenium ion -CH2.C(OR)2 and evidence is presented which accounts for the high rate of chain-breaking compared with that of other olefinic monomers.
SECTION B (Chapters 6-8)
This section is concerned with the properties of poly-ketene acetals. Acid hydrolysis of the polymers yields the corresponding poly-l,3-diketones, (-CH2CO-)n and various derivatives of both the keto and enol forms of these have been prepared.