Poly diblocks, hydrolysis

The physical properties of the acid- and ion-containing polymers are quite interesting. The storage moduli vs. temperature behavior (Figure 8) was determined by dynamic mechanical thermal analysis (DMTA) for the PS-PIBMA diblock precursor, the polystyrene diblock ionomer and the poly(styrene)-b-poly(isobutyl methacrylate-co-methacrylic acid) diblock. The last two samples were obtained by the KC>2 hydrolysis approach. It is important to note that these three curves are offset for clarity, i.e. the modulus of the precursor is not necessarily higher than the ionomer. In particular, one should note the same Tg of the polystyrene block before and after ionomer formation, and the extension of the rubbery plateau past 200°C. In contrast, flow occurred in... 

This was the first report using ATRP and sequential monomer addition. Hydrolysis of these diblock copolymer brushes yielded poly(styrene-fc-acrylic acid) brushes. 

The synthesis of poly(IB-fr-pivalolactone (PVL)) diblock copolymers was also recently accomplished by site-transformation of living cationic polymerization of IB to AROP of PVL, as shown in Scheme 14 [96, 97]. First, PIB with ffl-carboxylate potassium salt was prepared by capping living PIB with DPE followed by quenching with 1-methoxy-1-trimethylsiloxy-propene (MTSP), and hydrolysis of -methoxycarbonyl end groups. The -carboxyl-... 

The masked disilene procednre was nsed by Saknrai and co-workers to synthesize two samples of diblock copolymers of 1,1-dimethyl-2,2-dihexylsilane (MHS) and 2-(trimethylsilyloxy)ethyl methacrylate, which differed only in the relative lengths of their blocks. Hydrolysis of the trimethylsilyl protecting groups gave the corresponding amphiphilic diblock copolymers, poly(l,l-dimethyl-2,2-dihexyldisilene)-fe-poly(2-hydroxyethyl methacrylate) (PMH S-fc-PHEMA), depicted in Pig. 22 [48]. 

Hydrolysis of Poly(styrene-b-tBuA) Diblock Copolymer... 

Figure 4. FT-IR spectra of (A) polystyrene/poly(isobutyl methacrylate) diblock copolymer and (B) carboxylated block ionomer obtained after hydrolysis with K0-.

Polyisobutylene-b-poly(methacrylic acid) (PIB-b-PMAA) was prepared by hydrolysis of the ester group under acidic conditions, using HCl(aq) in dioxane. After hydrolysis a new amphiphilic diblock copolymer is formed as shown in Scheme 3. The resulting amphiphilic block copolymers form a stable polymeric emulsions in dioxane. 

In addition to ATRP and NMRP, RAFT has also been used in this transformation. As mentioned previously, block copolymers with desired properties can be prepared by careful selection of the CTA, initiator, and monomers. A novel methodology employing this transformation for the synthesis of well-defined AB diblock and ABA triblock copolymers of poly (vinyl alcohol) (PVA) and PEO was recently reported. For this purpose, mono- or difimctional PEOs with xanthate end group were synthesized by anionic polymerization and employed as CTAs in the RAFT polymerization of vinyl acetate (VAc) to yield well-defined PEO-b-PVAc and PVAc-l -PEO-l7-PVAc. Eventually, direct hydrolysis of acetate groups by sodium hydroxide in methanol solution and... 

David et al have tested these new diblock copolymers as additives for adhesion/anticorrosive properties of metals. In order to protect against corrosion, a coating system was prepared consisting of a blend of poly(VDF) (inhibiting water penetration) with poly(MMA)-Z)-poly(monophosphonic acrylate) diblock copolymer with 10 wt% [compared to poly(VDF)]. This diblock copolymer was obtained by atom transfer radical polymerization using post-functionalization and hydrolysis to introduce the phosphonic acid function onto the polymeric backbone. The anticorrosive properties of virgin poly(VDF) were also determined without any additive to be compared... 

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