Block Copolymers Prepared Through Transformation Techniques

Block Copolymers Prepared Through Transformation Techniques... 

Numerous examples exist of combining CRP methods with other polymerization techniques for preparation of block copolymers. Non-living polymerization methods like condensation, free-radical, and redox processes can easily be combined with CRP to produce novel materials. Transformation chemistry may be the only route to incorporate polymers like polysulfones (as described above), polyesters, or polyamides that are prepared solely through condensation processes into subsequent CRP to form block copolymers with vinyl monomers. The same can be said of polymers prepared through coupling techniques, like po-ly(phenylenevinylene) and poly(methylphenylsilylene), which can maintain their conductive or photoluminescence properties, but become easier to process... 

Non-living polymerization techniques can be combined with CRP methods to produce block copolymers. The first example of transforming a hydroxy functionality into an ATRP initiator was demonstrated by Gaynor and Matyjaszewski [223], who converted a polysulfone,prepared through the condensation polymerization of 4,4-difluorosulfone with an excess of bisphenol A, to an ATRP initiator by reaction with 2-bromopropionyl bromide for subsequent controlled polymerization reactions (cf. Scheme 26). The transformation proved to be quantitative and the macroinitiator (Mn=4030,Mw/Mn=1.5) was used for formation of triblock copolymers with St (Mn=10,700,Mw/Mn=l.l) or nBA (Mn=15,300,Mw/Mn=1.2) as shown in Fig. 31 [223]. DSC analysis provided evidence of the presence of two distinct blocks with Tg=153-159 °C (polysulfone) and 104 °C (pSt) or -41 °C (pBA). 

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