P-tert butoxystyrene

DHBCs of the type poly(p-hydroxystyrene-b-methaciylic acid) (PHOS-PMAA) were also synthesized via anionic polymerization followed by acidic hydrolysis [10]. Both blocks of the precursor poly(p-tert-butoxystyrene-b-tert-butylmethacrylate) (PtBOS-PtBMA) copolymers, formed by sequential addition of the protected monomers, could be deprotected in a single step giving the desired pH-responsive block copolymers. Figure 2. Hydrolysis was found to be nearly quantitative and resulted in a series of copolymers with well defined molecular characteristics and of variable composition. 

Different series of DHBCs were prepared from anionically synthesized poly(p-tert-butoxystyrene-b-ethylene oxide) (PtBOS-PEO) precursors [12], Post polynnerization acidic hydrolysis of the PtBOS block resulted in poly(p-hydroxystyrene-b-ethylene oxide) (PHOS-PEO) copolymers. Further functionalization of the PHOS block via a Mannich type aminomethylation reaction gave the poly[3,5-bis(dimethylaminomethylene)hydroxystyrene-b-ethylene oxide] (PNHOS-PEO) copolymers, as testified by FT-IR and NMR experiments. In these copolymers the PNHOS block carries two dimethylamino groups per monomeric imit that can be protonated in acidic media and weakly acidic phenolic groups that have their own pH sensitivity. The PNHOS-PEO block copolymers were further quatemized with... 

Benzene, iV AT-dimethylfcnmamide (DMF), dichlorometiiane, metiiyl methacrylate, tert-butyl methacrylate (TBMA) and p-terT-butoxystyrene (tBOSt) were purchased and distilled before use. 2,2 -Azobisisobutyronitrile (AIBN) was purified by recrystallization from etiianol. 9-Fluorenilideneimino p-toluenesulfonate (FITS) (72), neopentyl styrenesulfonate (NPSS) (73), cyclohexyl styrenesulfonate (CHSS) (14) and phenyl styrenesulfonate (PhSS) were prepared according to the lito ture. Qxone (potassium... 

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