Photochemically Mediated Atom Transfer Radical Polymerization of Methyl Methacrylate Using ppm Amounts of Catalyst

ATRP with a light switch: photoinduced ATRP using a household fluorescent lamp

We report on photoinduced ATRP in solution and from surfaces using a standard fluorescent lamp as the light source.

Photoinduced sequence-control via one pot living radical polymerization of acrylates

A versatile and inexpensive photochemical platform for the preparation of high-order multiblock functional materials.

Synthesis, characterization, and computational study of potential itaconimide-based initiators for atom transfer radical polymerization

We report synthesis of potential initiators1a-Br,2a-Br, and3a-Br for the ATRP ofN-phenylitaconimide and MMA. We find (i) good agreement between experimentally determined and calculatedK_ATRPvalues (ii)3a-Br performs better than the commercially available initiator.

pH-sensitive membranes prepared with poly(methyl methacrylate) grafted poly(vinylidene fluoride) via ultraviolet irradiation-induced atom transfer radical polymerization

Ultraviolet (UV) irradiation induced atom transfer radical polymerization (ATRP) was performed to graft poly(methyl methacrylate) (PMMA) onto poly(vinylidene fluoride) (PVDF) and obtain copolymer (PVDF-g-PMMA).

Determination of ATRP Equilibrium Constants under Polymerization Conditions

Atom transfer radical polymerization (ATRP) equilibrium constants (K_ATRP) were measured during polymerization of methyl acrylate (MA) with Cu^IBr/Cu^IIBr₂ in either dimethyl sulfoxide (DMSO) or acetonitrile (MeCN) in the presence of either tris(2-pyridylmethyl)amine (TPMA) or tris[2-(dimethylamino)ethyl]amine (Me₆TREN) as the ligand and with ethyl 2-bromopropionate as the initiator. The ln(K_ATRP) values changed linearly with the volume fraction of solvents in the reaction medium, allowing extrapolation of the values for K_ATRP to bulk conditions, which were 2 × 10^-9 and 3 × 10^-8 for TPMA and Me₆TREN ligands at 25 °C, respectively. The temperature effect on K_ATRP values was studied in MA/MeCN = 1/1 (v/v) with TPMA as the ligand in the temperature range from 0 to 60 °C. The K_ATRP values increased with temperature providing ΔH = 36 kJ mol^-1 in MeCN.

Inorganic Sulfites: Efficient Reducing Agents and Supplemental Activators for Atom Transfer Radical Polymerization

Inorganic sulfites such as sodium dithionite (Na₂S₂O₄), sodium metabisulfite (Na₂S₂O₅), and sodium bisulfite (NaHSO₃) have been studied as reducing agents for atom transfer radical polymerization (ATRP). They act not only as very efficient reducing agents but also as supplemental activators for SARA (supplemental activator and reducing agent) ATRP of methyl acrylate in DMSO at ambient temperature. In combination with Cu(II)Br₂/Me₆TREN, they produced poly(methyl acrylate) with controlled molecular weight, low dispersity (M_w/M_n = 1.05), and well-defined chain-end functionality. Sulfites are eco-friendly, approved by FDA as food and beverage additives, and used commercially in many industrial processes.

Visible Light and Sunlight Photoinduced ATRP with ppm of Cu Catalyst

Photochemically induced ATRP was performed with visible light and sunlight in the presence of parts per million (ppm) copper catalysts. Illumination of the reaction mixture yielded polymerization in case of 392 and 450 nm light but not for 631 nm light. Sunlight was also a viable source for the photoinduced ATRP. Control experiments suggest photoreduction of the Cu^II complex (ligand to metal charge transfer in the excited state), yielding a Cu^I complex, and a bromine radical that can initiate polymerization. No photoactivation of Cu^I complex was detected. This implies that the mechanism of ATRP in the presence of light is a hybrid of ICAR and ARGET ATRP. The method was also used to synthesize block copolymers and polymerizations in water.