Synthesis of Functional Syndiotactic Polystyrene Copolymers with Graft and Block Structures by Nitroxide-Mediated Living Radical Polymerization

Abstract

In this study, synthesis of controlled graft copolymers onto syndiotactic polystyrene using nitroxide-mediated living radical polymerization and 2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO) iniferter is reported. Syndiotactic polystyrene has been synthesized using half-sandwich titanocene/ methylaluminoxane catalyst in homogenous conditions. Then, a-phenyl chloroacetylation of syndiotactic polystyrene was accomplished in a heterogeneous process using carbon disulfide as dispersing medium and a-phenyl chloroacetyl chloride and anhydrous aluminum chloride as acetylating agent and catalyst, respectively. Then, 1-hydroxy 2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO-OH) was synthesized by the reduction of TEMPO with sodium ascorbate. This functional nitroxyl compound was coupled with arylated syndiotactic polystyrene. The graft copolymerizations of styrene and methyl styrene were initiated by arylated syndiotactic polystyrene carrying TEMPO groups as a macroinitiator. The product of polymerization was then heated in the presence of styrene and methyl styrene to form graft copolymer. The structure of obtained copolymer was investigated by 1 H-NMR, and Fourier transform-infrared spectroscopy, and thermal behavior of copolymers was performed by differential scanning calorimetry analyses.

Hydrogel−Solid Hybrid Materials for Biomedical Applications Enabled by Surface‐Embedded Radicals

“…The spectral lines at wavenumbers 2852, 2926,1431, 1384, 1346, 1304 cm −1 , and the region between 3500 and 3100 cm −1 are attributed to 4‐hydroxy TEMPO. [ 61–63 ] These lines are visible both before and after incubation with hydrogel, whereas the hydrogel peaks are not present. After the application of hydrogel, a very small peak appeared on the shoulder (1662 cm −1 ) of the TEMPO line at 1650 cm −1 .…”

Engineering of Syndiotactic and Isotactic Polystyrene-Based Copolymers via Stereoselective Catalytic Polymerization

“…Further Baeyer-Villiger oxidation of sPS- graft -aPS polymers also allowed to transform the ketone into an ester function, the latter could be hydrolyzed to recover both sPS and aPS homopolymers [ 104 ]. It was also demonstrated that a sPS-graft-(aPS- co -a( p -Me)S) terpolymer can be obtained by simultaneous radical copolymerization of styrene and p-methylstyrene initiated by sPS- graft -TEMPO macroinitiator [ 105 ].…”

Synthesis of conductive PSt-g-PANi/TiO2 nanocomposites by metal catalyzed and chemical oxidative polymerization

“…These composites are attractive because they can combine with the properties of other compounds, and the composites of PANI with graphite, [7,8] carbon nanotubes [9] and carbon black (CB) have been accepted to effectively improve the electric conductivity. As well as, encapsulation of metal nanoparticles into CPs results in hybrid organicinorganic nanocomposites that exhibit enhanced thermal stability, electrochemical, catalytic, magnetic, mechanical, Downloaded by [RMIT University Library] at 08: 48 25 June 2016 polymerization, using stable nitroxide radicals such as TEMPO, [36][37][38][39][40][41][42][43][44] and atom transfer radical polymerization (ATRP). [45][46][47][48][49][50][51][52][53] Because ATRP allows better control over the molecular weight and distribution of the target polymer, much attention has been paid to the use of this polymerization method in the synthesis of polymer brushes from a surface.…”