Synthesis of Polystyrene and Poly(methyl methacrylate) Each with a Phenyl Seleno Group at Terminal Chain End by Radical Polymerization in the Presence of Benzyl Phenyl Selenide as a Photoiniferter

Abstract

ABSTRACT:The photopolymerization of styrene with benzyl phenyl selenide proceeded smoothly to give polystyrene having benzyl and phenylsclcno groups at a-and w-chain ends, respectively, and the degree of functionality was 0.95. In a limited range of conversion, both the polymer yields and number average of molecular weights (M.) increased with the reaction time and the M. linearly increased with yield. The addition of styrene to the polystyrene with irradiation increased the molecular weight of the polymer. In the photopolymerization of methyl methacrylate, similar polymerization behavior was observed. The tacticity of the poly(methyl methacrylatc) was in good agreement with that prepared by radical mechanism. Photoirradiation of polystyrene having phenylseleno group at the w-end in the presence of methyl methacrylate effectively afforded a block copolymer of styrene and methyl methacrylate.KEY WORDS Radical Polymerization / Benzyl Phenyl Selenide / p-Methoxybenzyl p-Trimethylsilylphenyl Selenide / Photoiniferter / Polymeric Photoiniferter / Block Copolymer / End functional polymers are useful precursors for novel block, graft and star polymers. The synthesis of end functional polymers are conventionally prepared by anionic, cationic, and radical polymerization. 1 -11 Preparation by radical polymerization with iniferter method is quite convenient and hence widely used. 12 -16 Otsu and coworkers 1 7 -19 proposed iniferter for the design of the polymer chain end structure. An iniferter is an initiator which also functions as chain transfer agent and/or primary radical terminator. It is attractive for preparing simple block copolymers and more complex polymer architectures using various monomers which do not polymerize by an ionic mechanism. 20 -23 Iniferters mainly use organic sulfur compounds such as tetraalkylthiuram disulfides, dithiocarbamates, and tetramethylene disulfide.We recently reported that photopolymerization of styrene in the presence of di phenyl diselenide, 24 similar to the case of tetraalkylthiuram disulfides 25 to afford polystyrene carrying phenylseleno groups at both chain ends (P-A) (eq I). By the irradiation of light to the polymers with selenide moieties (P-A) in styrene, polystyrene with higher molecular weight (P-B) was obtainOse-Se-Q + n P-A + m CH2=3

Radical Polymerization of p-Substituted Styrenes with Benzyl Phenyl Selenide as Photoiniferter

“…This indicates that functionalized poly(p-substituted styrene )s prepared by this method contain benzyl and phenylseleno groups at ll(-and w-chain ends, respectively. The mechanisms are thus the same as in the previous report 7 in which the monomer was inserted into the carbon-selenium bond (eq 3-5).…”

“…17 BPSE-1 Vmax = 280, c: = 14000 in ethanol) and p-methoxybenzyl p-trimethylsilylphenyl selenide (BPSE-2) (A.max=280, c=20000 in ethanol) were prepared as in previous papers. 7 Solvents were purified by distillation after appropriate drying. Other reagents were obtained commercially and used without further purification.…”

“…5 · 6 More recently, we reported the synthesis of the end functional polystyrene and poly(methyl methacrylate) by radical polymerization in the presence of benzyl phenyl selenide (BPSE-1) as photoiniferter. 7 The resulting polystyrene (IPS) had benzyl and phenylseleno groups at 'X-and w-chain ends, respectively ( eq I). Photoirradiation of this polymeric photoiniferter in the presence of methyl methacrylate (MMA) afforded a block copolymer (lPS-b-PMMA) of styrene (St) and MMA (eq 2).…”

Controlled Radical Polymerization of Vaporized Vinyl Monomers on Solid Surfaces under UV Irradiation

“…A sharp singlet at 3.65 ppm in the spectrum was assigned to -COOCH 3 in a repeated MMA unit sequence and the peak profile in the range of d ¼ 6.3-7.2 ppm also shows the characteristic profile of aromatic ring protons in a continuous St unit sequence. [39,41,45] Therefore, the as-polymerized product should be a block or graft copolymer, and/ or a blend of each homopolymer.…”

Synthesis and Radical Polymerization of p-Phenylselenomethylstyrene and Applications to Graft Copolymers

“…13 We also reported the synthesis of end functional polystyrene by radical polymerization in the presence of benzyl phenyl selenide (BPSE) as a photoiniferter. 14 The resulting polystyrene (PST) had benzyl and phenylseleno groups at rx-and w-chain ends, respectively. Photoirradiation of this end functional polystyrene as a polymeric photoiniferter in the presence of methyl methacrylate (MMA) effectively afforded a block copolymer (PST-b-PMMA) of styrene and MMA (eq 1).…”