Synthesis of PMMA‐PTHF‐PMMA and PMMA‐PTHF‐PST linear and star block copolymers

Abstract

Combination of cationic, redox free radical, and thermal free radical polymerizations was performed to obtain linear and star polytetramethylene oxide (poly-THF)-polymethyl methacrylate (PMMA)/polystyrene (PSt) multiblock copolymers. Cationic polymerization of THF was initiated by the mixture of AgSbF 6 and bis(4,4Ј bromomethyl benzoyl) peroxide (BBP) or bis (3,5,3Ј,5Ј dibromomethyl benzoyl) peroxide (BDBP) at 20°C to obtain linear and star poly-THF initiators with M w varying from 7,500 to 59,000 Da. Poly-THF samples with hydroxyl ends were used in the methyl methacrylate (MMA) polymerization in the presence of Ce(IV) salt at 40°C to obtain poly(THF-b-MMA) block copolymers containing the peroxide group in the middle. Poly(MMA-b-THF) linear and star block copolymers having the peroxide group in the chain were used in the polymerization of methyl methacrylate (MMA) and styrene (St) at 80°C to obtain PMMA-b-PTHF-b-PMMA and PMMAb-PTHF-b-PSt linear and star multiblock copolymers. Polymers obtained were characterizated by GPC, FT-IR, DSC, TGA, 1 H-NMR, and 13 C-NMR techniques and the fractional precipitation method.

Synthesis of a New Macroperoxy Initiator with Methyl Methacrylate and T-Butyl Peroxy Ester by Atom Transfer Radical Polymerization and Copolymerization with Conventional Vinyl Monomers

“…The poly-MMA macroperoxy initiators showed the characteristic macroinitiator behavior in the copolymerization of S (14,29,30). Table 2 shows the conditions and the results of the polymerization.…”

“…Macrointermediates such as macroinitiators, macromonomers, macrocrosslinkers are important in polymer modification leading to block and graft copolymers (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). Macromonomeric initiators which behave as a macromonomer, macroinitiator, or macrocrosslinker have attracted great interest because they lead to synthesized crosslinked or branched block copolymers.…”

The synthesis of PHA‐g‐(PTHF‐b‐PMMA) multiblock/graft copolymers by combination of cationic and radical polymerization

“…Scheme indicates that chlorides of PHA‐Cl react with AgSbF 6 resulting in the precipitation of AgCl and formation of carbocation on polyesters where SbF is the counterion. These carbocations initiate the polymerization of THF to form PHA‐ g ‐PTHF graft copolymers 47–50. After the reaction was completed, polymer solution separated from AgCl(s) by decantation was precipitated in water/methanol mixture.…”

“…In this manner, transformation reactions to polymer anion,33–38 cation to radical transformation reactions,39–42 and polymer anion to polymer cation43, 44 were successfully used to prepare block/graft copolymers. Among these methods, the cation to radical transformation reactions are generally based on preparing poly‐THF having peroxidic or azo groups45–50 to insert PTHF blocks in the copolymer structure, which enhance the flexibility and thermoplasticity of the copolymer. The soft poly‐THF blocks enhance the flexibility and thermoplasticity of the copolymer.…”

Synthesis, characterization and surface properties of amphiphilic polystyrene-b-polypropylene glycol block copolymers

“…Macroinitiators generating radicals can be classiWed as macroazoinitiators, azoperoxidic initiators, redox macroinitiators [11,12] and macrophotoinitiators [13]. Macroazoinitiators which can be prepared by the condensation reactions of a prepolymer with azobis-isobutyronitrile [14], 4,4Јazobis (4-cyanopentanoyl chloride) [15,16], 4,4Јazobiscy-anopentanol [17,18] provide a useful means of preparing amphiphilic block copolymers via radical process.…”