Amphiphilic block copolymers containing thermally degradable poly(phthalaldehyde) blocks

In this study, the preparation of a new class of amphiphilic block copolymers consisting of a poly(phthalaldehyde) (PPA) block and hydrophilic poly(alkylene oxide) blocks is described. PPA was prepared by ionic cyclopolymerization. A telechelic polymer block was prepared by endcapping of the PPA by a bifunctional reagent carrying isocyanate and isothiocyanate groups. As the second block, monoamino‐terminated poly(alkylene oxide)s (Surfonamines®, also known as Jeffamines®) were chosen. These polymers could be readily coupled to the PPA telechel and gave amphiphlic, mainly ABA‐type block copolymers. The PPA block of these products can be selectively depolymerized at moderate temperature. The block copolymers were characterized by dual‐detection size exclusion chromatography, and the defined and stepwise thermal decomposition of the two different block types were shown by thermogravimetric analysis.