Sukumar Maiti

Donor-Acceptor Complexes in Copolymerization. XXXVI. Alternating Diene-Dienophile Copolymers. 4. Copolymerization of Furan and 2-Methylfuran with Maleic Anhydride

Abstract The copolymerization of furan and 2-methylfuran with maleic anhydride in the presence of a radical catalyst yields equimolar, alternating copolymers in which the furan units have a 2,5-linkage (NMR and IR). The copolymerization appears to have a floor temperature of about 40°C. The furan-maleic anhydride Diels-Alder adduct polymerizes in solution in the presence of a radical catalyst at temperatures above 60°C to yield the identical copolymer as is obtained from the monomers. The adduct undergoes a retrograde reaction above 60°C to regenerate the monomers which then copolymerize through excitation of the ground state comonomer charge transfer complex.

Donor-Acceptor Complexes in Copolymerization. XXXVII. Alternating Diene-Dienophile Copolymers. 5. Formation of Conjugated Diene-Maleic Anhydride Copolymers through Retrograde Dissociation of Furan-Maleic Anhydride Diels-Alder Adduct

Abstract The equimolar, alternating copolymer of isoprene, as well as other conjugated dienes, and maleic anhydride is formed by the radical catalyzed reaction of the conjugated diene with maleic anhydride in the presence of furan as well as with the furan-maleic anhydride Diels-Alder adduct. The retrograde dissociation of the cyclic adduct above 60°C regenerates furan and maleic anhydride which in the presence of isoprene forms the isoprene-maleic anhydride ground state complex. The latter yields the corresponding cyclic adduct in the absence of a radical catalyst and undergoes excitation and homopolymerization in the presence of a catalyst.

Donor-Acceptor Complexes in Copolymerization. XXXVIII. Photoinduced Polymerization of Comonomer Charge Transfer Complexes of Styrene with Methyl Methacrylate and Acrylonitrile

Abstract The copolymerizations of styrene (S) with acrylonitrile (AN) and with methyl methacrylate (MMA) under UV irradiation yield radical copolymers. The copolymerization of S and MMA in the presence of AlEt3 yields MMA-rich copolymer when S/MMA=1 under UV and equimolar, alternating copolymer when S/MMA ≥ 1 in the dark and S/MMA < 1 under UV. The copolymerization of S and AN in the presence of AlEt3 in the dark and under UV yields equimolar, alternating copolymer when S/AN=1 and nonequimolar copolymer when S/AN < 1. The copolymerization of S and AN in the presence of AlEt1.5Cl1.5 (EASC) under light yields equimolar, alternating copolymer when S/AN=25/75-75/25. The terpolymerization of S, MMA, and AN (100/50/50) in the presence of EASC at 10-90°C under UV and in the dark in the absence as well as in the presence of benzoyl

Donor-Acceptor Complexes in Copolymerization. XXXIX. Alternating Diene-Dienophile Copolymers. 6. Photosensitized Copolymerization of Conjugated Dienes and Maleic Anhydride

Abstract Equimolar, alternating copolymers are produced when solutions of conjugated dienes and maleic anhydride are subjected to 2537 A UV light in the presence of photosen-sitizers or 3000 A or higher wavelength light in the absence or presence of sensitizers. The yield of copolymer is highest when the sensitizer has ET < 74 kcal/mole. The copolymers are insoluble in polar organic solvents when the sensitizer has ET < 75.