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

Abstract

A new and promising method for the diversification of microbial polyesters based on chemical modifications is introduced. Poly(3‐hydroxy alkanoate)‐g‐(poly(tetrahydrofuran)‐b‐poly(methyl methacrylate)) (PHA‐g‐(PTHF‐b‐PMMA)) multigraft copolymers were synthesized by the combination of cationic and free radical polymerization. PHA‐g‐PTHF graft copolymer was obtained by the cationic polymerization of THF initiated by the carbonium cations generated from the chlorinated PHAs, poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), and poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBHx) in the presence of AgSbF6. Therefore, PHA‐g‐PTHF graft copolymers with hydroxyl ends were produced. In the presence of Ce+4 salt, these hydroxyl ends of the graft copolymer can initiate the redox polymerization of MMA to obtain PHA‐g‐(PTHF‐b‐PMMA) multigraft copolymer. Polymers obtained were purified by fractional precipitation. In this manner, their γ‐values (volume ratio of nonsolvent to the solvent) were also determined. Their molecular weights were determined by GPC technique. The structures were elucidated using 1H‐NMR and FTIR spectroscopy. Thermal analyses of the products were carried out using differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Polyhydroxyalkanoates: Properties and chemical modification approaches for their functionalization

“…A copolymer is comprised of two different polymer units; in the case of graft copolymers one or more side chains are attached to the main chains as its blocks. Grafting is a convenient way to synthesize a copolymer with new properties with minimum loss of original properties of the polymer . Different types of grafting methods are discussed below.…”

“…This graft copolymer was with hydroxyl end groups because the carbonium cation was generated from PHBV and PHBx. In the presence of cerium salts these hydroxyl end copolymers can start redox polymerization of polymethyle methacrylate and PHA‐g‐(PTHF‐b‐PMMA) graft‐copolymer would be achieved . Cationic grafting has the main advantage of controlling molecular weight of a grafted copolymer.…”

Synthesis of Polylactide-b-Poly (Dimethyl Siloxane) Block Copolymers and Their Blends with Pure Polylactide

“…The polyesters can be degraded during reflux conditions at 175°C even in the absence of any other reagent such as base catalyst [49].…”

Calcium Salts of Tungstophoric Acid Supported on Silica as Novel Catalysts for Tetrahydrofuran Polymerization

“…Polytetramethylene ether glycol (PTMG) is known to be an important material for synthesis block polyurethane and other polymers [1][2][3], which is obtained by the ring-opening polymerization of tetrahydrofuran. Heteropolyacids have many applications in science researches [4][5][6][7] and industrial production [8], and it could also replace HF, H 2 SO 4 , and other traditional inorganic corrosive acids in the synthesis of polytetrahydrofuran in mild conditions [9,10].…”