Publication Details (including relevant citation information):
Journal of Macromolecular Science - Pure and Applied Chemistry, Vol. A31, No. 12, pp. 1941-1951 (1994)
The synthesis, characterization, and select emulsification properties of T- and comb-shaped sequential copolymers comprising a poly(ethylene oxide) (I) backbone carrying one or multiple polyisobutylene (PIB) branches linked by acetal groups are described. Conditions were developed under which PIBs carrying an aldehyde endgroup (PIB-CHO) react with commercially available I carrying one or two terminal OH groups, i.e., Me(OCH2CH2)nOH and H(OCH2CH2)nOH to yield, Me(OCH2CH2)nOCH(PIB)O(CH2CH2O)Me or H(OCH2CH2)nO[CH(PIB)O(CH2CH2O)n]mH, resp. The microarchitecture and compn. of these copolymers can be influenced by the CHO/OH ratio and the mol. wt. of the prepolymers. These sequential copolymers form very stable oil-in-water emulsions. The linking acetal group is resistant to hydrolysis in aq. suspension at room temp., most likely because of steric protection afforded by the bulky water-repellent PIB blocks. However, the acetal linking groups can be rapidly cleaved by 1N aq. HCl at .apprx.100°.
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