| Budget Amount *help |
¥14,000,000 (Direct Cost: ¥14,000,000)
Fiscal Year 2005: ¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥10,300,000 (Direct Cost: ¥10,300,000)
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| Research Abstract |
This research is directed to developing the stereospecific living radical polymerization by effectively combining the living and stereospecific radical polymerizations for the simultaneous control of the molecular weights and tacticity. The key to the success is to find appropriate combinations where one of the controls should not be lost by the other component. We found that several combinations induced stereospecific living radical polymerizations of various monomers such as methacrylates, acrylamides, vinyl acetate, and N-vinylpyrrolidone. The followings summarize each system.
(1) Ruthenium-catalyzed living radical polymerizations of methacrylates in fluoroalcohols and aprotic solvents
Methyl methacrylate was polymerized with Ru(Cp^*)Cl(PPh_3)_2 in (CF_3)_3COH to give polymers with narrow molecular weight distributions (MWDs) and high syndiotacticity (M_w/M_n=1.07, r=88%). For the polymerization of 2-hydroxyethyl methacrylate, DMF as a solvent induced syndiospecific living radical polymerization in the presence of Ru(Cp^*)Cl(PPh_3)_2. By using the polymerizations, stereoblock polymers were obtained.
(2) Iron-catalyzed living radical polymerizations of acrylamides in the presence of metal triflates
N,N-Dimethylacrylamide was polymerized with [FeCp(CO)_2]_2 in the presence of Y(OTf)_3 to result in the polymers with controlled molecular weights and high isotacticity (M_w/M_n=1.87, m=82%).
(3) Iodine-transfer radical polymerizations of vinyl acetate in fluoroalcohols
Iodine-transfer radical polymerization of vinyl acetate was done in m-C_6H_4{C(CF_3)_2OH}_2 to result in the polymers with narrow MWDs and relatively high syndiotacticity (M_W/M_n=1.20, r=59%).
(4) Xanthate-mediated radical polymerizations of N-vinylpyrrolidone in fluoroalcohols
Xanthate was employed for the control of molecular weight in radical polymerization of N-vinylpyrrolidone in (CF_3)_3COH to result in the polymer with controlled molecular weights and high syndiospecificity (M w/M_n=1.28, r=60%).
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