Segmented Copolymers by Mechanistic Transformations

A Renaissance in Living Cationic Polymerization

“…Since this successful synthesis of a block copolymer, a large variety of block copolymers have been prepared via sequential living cationic polymerizations and/or an intermediate capping reaction, 363 as shown in Figure 21. Various transformations from cationic to other living polymerizations, 364 known as an alternative method for block copolymer synthesis, are described in a later section (see section 6.2).…”

Dixanthate-terminated poly(butylene terephthalate). A novel RAFT/MADIX agent for the synthesis of well-defined triblock copolymers resulting from consecutive step- and chain-growth polymerization processes

“…In a second step, the transformation of the bromopropionate group into xanthate functionality was readily accomplished in acetone with a small excess of O-ethyl xanthic acid potassium salt (1.3 equivalent). Quantitative conversion was confirmed by 1 ). Purity of 5 was also confirmed by GC-MS analysis.…”

“…In contrast, all the PBTs of the study were found to be insoluble in pure chloroform. The solubility of the triblock copolymers was further studied by 1 H NMR analysis (Table 2). Experimental molar fraction of PBT (x PBT exp ) was determined by comparing two distinct 1 H NMR signals characteristic of the protons of the repeating units of each block.…”

“…Synthesis of ABA triblock copolymers with a PBT mid-block by RAFT/MADIX polymerization of n-BA and t-BA and t-BAm from a PBT telechelic macro-chain transfer agent at T ¼ 70 C Conversion determined by1 H NMR (CDCl 3 ). b M n (theory) ¼ ([M] 0 /[PBT] 0 )  conv  MW(M) + M n,NMR PBT .…”