Polymerization Mechanism of Methyl Methacrylate Initiated by Ethyl Acetate/t-BuP_4
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摘要
The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chromatography(SEC) measurements, and nuclear magnetic resonance(NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile,the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t-BuP_4 for preparing polymers with narrow molecular weight distribution.
The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chromatography(SEC) measurements, and nuclear magnetic resonance(NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile,the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t-BuP_4 for preparing polymers with narrow molecular weight distribution.
The anionic polymerization of methyl methacrylate(MMA) was carried out using phosphazene base t-BuP_4 and ethyl acetate(EA) as the catalyst and the initiator, respectively. Gas chromatography(GC), size exclusion chromatography(SEC) measurements, and nuclear magnetic resonance(NMR) analyses were used to reveal the polymerization mechanism and to confirm the polymer structure. The results confirmed the proposed polymerization mechanism and the polymer structure, while the initiator efficiency was low. Meanwhile,the initiation by methoxy anion coming from hydrolysis of the ester bond in MMA was also observed. As a result, there is a marked deviation between the theoretical molecular weight and the measured molecular weight, and it is essential to carry out the polymerization at excessive dosage of t-BuP_4 for preparing polymers with narrow molecular weight distribution.
引文
1 Schwesinger, R.; Schlemper, H. Peralkylated polyaminophosphazenes-extremely strong, neutral nitrogen bases. Angew.Chem. Int. Ed. 1987, 26, 1167-1169.
2 Schwesinger, R.; Willaredt, J.; Schlemper, H.; Keller, M.;Schmitt, D.; Fritz, H. Novel, very strong, uncharged auxiliary bases; design and synthesis of monomeric and polymer-bound triaminoiminophosphorane bases of broadly varied steric demand. Chem. Ber. 1994,127, 2435-2454.
3 Schwesinger,R.; Schlemper,H.; Hasenfratz,C.; Willaredt, J.;Dambacher,T.; Breuer,T.; Ottaway,C.; Fletschinger, M.;Boele,J.; Fritz,H.; Putzas,D.; Rotter,H. W.; Bordwell,F. G.;Satish, A. V.; Ji, G. Z.; Peters, E. M.; Peters, K.; Schnering, H.G. V.; Walz, L. Extremely strong, uncharged auxiliary bases;monomeric and polymer-supported polyaminophosphazenes(P2-P5).Liebigs Ann. 1996, 7, 1055-1081.
4 Kaupmees,K.; Trummal,A.; Leito, I. Basicities of strong basesin water:A computational study. Croat. Chem. Acta 2014, 87,385-395.
5 Pietzonka,T.; Seebach,D. Alkylations of(R,R)-2-t-butyl-6-methyl-1,3-dioxan-4-ones which are not possible with lithium amides may be achieved with a schwesinger P4 Base. Chem.Ber. 1991,124, 1837-1843.
6 Pietzonka, T.; Seebach, D. N-Perbenzylation of oligopeptides with P4-phosphazene base; a new protecting-group technique for modification and solubilization of peptides in apolar organic solvents.Angew. Chem. Int. Ed. 1992, 31, 1481-1482.
7 Pietzonka, T.; Seebach, D. The P4-phosphazene base as part of a new metal-free initiator system for the anionic polymerization of methyl methacrylate. Angew. Chem. Int. Ed. 1993, 32,716-717.
8 Isono, T. Synthesis of star-and figure-eight-shaped polyethers by t-Bu-P4-catalyzed ring-opening polymerization of butylene oxide. Macromolecules 2013, 46, 3841-3849.
9 Song, Q. L.; Hu,S. Y.; Zhao, J. P.; Zhang,G. Z. Organocatalytic copolymerization of mixed type monomers. Chinese J.Polym. Sci. 2017, 35, 581-601.
10 Kondo, Y. in Superbases for organic synthesis:Guanidines,amidines,phosphazenes and related organocatalysts, John Wiley&Sons Ltd.,2009, pp. 145-185.
11 Boileau, S.; Illy, N. Activation in anionic polymerization:Why phosphazene bases are very exciting promoters.Prog.Polym.Sci. 2011,36, 1132-1151.
12 Ottou,W. N.; Sardon,H.; Mecerreyes,D.; Vignolle,J.; Taton,D. Update and challenges in organo-mediated polymerization reactions. Prog. Polym. Sci. 2016, 56, 64-115.
13 Hui S. Y.; Zhao, J. P.; Zhang, G. Z.; Schlaad, H. Macromolecular architectures through organocatalysis. Prog. Polym. Sci.2017, 74, 34-77.
14 Hong, M.; Chen, E. Y. X. Towards truly sustainable polymers:A metal-free recyclable polyester from biorenewable nonstrained y-butyrolactone. Angew. Chem. Int. Ed. 2016,55,4188-4193.
15 Hong,M.; Tang,X. Y.; Newell,B. S.; Chen,E. Y. X."Nonstrained"y-butyrolactone-based copolyesters:Copolymerization characteristics and composition-dependent(thermal, eutectic, cocrystallization, and degradation)properties. Macromolecules 2017, 50, 8469-8479.
16 Song,Q. L.; Xia,Y. N.; Hu,S. Y.; Zhao, J. P.; Zhang,G. Z.Tuning the crystallinity and degradability of PCL by organocatalytic copolymerization withδ-hexalactone. Polymer2016,102, 248-255.
17 Zhang,L.; Nederberg,F.; Messman,J. M.; Pratt,R. C.;Hedrick, J. L.; Wade, C. G. Organocatalytic stereoselective ring-opening polymerization of lactide with dimeric phosphazene bases. J. Am. Chem. Soc. 2007,129, 12610-12611.
18 Liu, J. J.; Chen, C.; Li, Z. J.; Wu, W. Z.; Zhi, X.; Zhang, Q. G.;Wu, H.; Wang, X.; Cui, S. D.; Guo, K. A squaramide and tertiary amine:An excellent hydrogen-bonding pair organocatalyst for living polymerization. Polym. Chem. 2015,6,3754-3757.
19 Liu, S. F.; Ren, C. L.; Zhao, N.; Shen, Y.; Li, Z. B. Phosphazene bases as organocatalysts for ring-opening polymerization of cyclic esters. Macromol. Rapid Commun. 2018, 39,1800485.
20 Li,Y. X.; Zhao, N.; Wei, C. Z.; Sun, A. B.; Liu,S. F.; Li,Z. B.Binary organocatalytic system for ring-opening polymerization ofε-caprolactone andδ-valerolactone:Synergetic effects for enhanced selectivity. Eur. Polym. J. 2019, 111, 11-19.
21 Liu, S. F.; Li, H. K.; Zhao, N.; Li, Z. B. Stereoselective ringopening polymerization of rac-lactide using organocatalytic cyclic trimeric phosphazene base. ACS Macro Lett. 2018, 7,624-628.
22 Dentzer, L.; Bray, C.; Noinville, S.; Illy, N.; Guegan, P. Phosphazene-promoted metal-free ring-opening polymerization of1,2-epoxybutane initiated by secondary amides. Macromolecules 2015, 48, 7755-7764.
23 Hassouna, L.; Illy, N.; Guegan, P. Phosphazene/triisobutylaluminum-promoted anionic ring-opening polymerization of 1,2-epoxybutane initiated by secondary carbamates. Polym. Chem.2017, 8, 4005-4013.
24 Zhang, H. X.; Hu, S. Y.; Zhao, J. P.; Zhang, G. Z. Phosphazene-catalyzed alternating copolymerization of dihydrocoumarin and ethylene oxide:Weaker is better. Macromolecules2017, 50,4198-4205.
25 Zhang,J.;Liu,Q.;Ren,H.J.;Zhang,N.J.;Li,P.F.;Yang,K.Phosphoniums as catalysts for metal-free polymerization:Synthesis of well-defined poly(propylene oxide). J. Mol Struc.2017, 1148, 421-428.
26 Xia, Y. N.; Zhao, J. P. Macromolecular architectures based on organocatalytic ring-opening(co)polymerization of epoxides.Polymer 2018, 143, 343-361.
27 EBwein, B.; Molenberg, A.; Moller, M. Use of polyiminophosphazene bases for ring-opening polymerizations. Macromol.Symp. 1996, 107, 331-340.
28 Molenberg, A.; Moller, M. A fast catalyst system for the ringopening polymerization of cyclosiloxanes. Macromol.Rapid Commun. 1995, 16, 449-453.
29 Pibre, G.; Chaumont, P.; Fleury, E.; Cassagnau, P. Ring-opening polymerization of decamethylcyclopentasiloxane initiated by a superbase:Kinetics and rheology. Polymer 2008, 49,234-240.
30 Dyke, M. E. V.; Clarson, S. J. Reaction kinetics for the anionic ring-opening polymerization of tetraphenyltetramethylcyclotetrasiloxane using a fast initiator system. J. Inorg. Organomet.Polym. 1998, 8, 111-117.
31 Samuel,C.; Chalamet,Y.; Boisson,F.; Majeste, J.; Becquart,F.; Fleury, E. Highly efficient metal-free organic catalysts to design new environmentally friendly starch-based blends. J.Polym. Sci., Part A:Polym. Chem. 2014, 52, 493-503.
32 Brignou, P.; Gil, M. P.; Casagrande, O.; Carpentier, J. F.; Guillaume, S. M. Polycarbonates derived from green acids:Ringopening polymerization of seven-membered cyclic carbonates.Macromolecules 2010, 43, 8007-8017.
33 Chen, J. L.; Li, M. S.; He, W. J.; Tao, Y. H.; Wang, X. H. Facile organocatalyzed synthesis of poly(ε-lysine)under mild conditions. Macromolecules 2017, 50, 9128-9134.
34 Jr, W. M.; Campbell, G. C.; Davidson, F. Poly(aminophosphazene)s and protophosphatranes mimic classical strong anionic base catalysts in the anionic ring-opening polymerization of lactams.Macromolecules 1996, 29, 6475-6480.
35 Borner, H. G.; Heitz, W. Anionic polymerization of butyl acrylate with metal free initiator systems containing[1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphor-anylidenamino]-2λ5,4λ5-catenadi(phosphazene)] base(P4-tert-butyl-phosphazene base). Macromol. Chem. Phys. 1998,199, 1815-1820.
36 Kakuchi, T.; Chen,Y.; Kitakado,J.; Mori, K.; Fuchise,K.;Satoh, T. Organic superbase as an efficient catalyst for group transfer polymerization of methyl methacrylate. Macromolec ules 2011,44, 4641-4647.
37 Weideman,I.; Pfukwa,R.; Klumperman,B. Phosphazene base promoted anionic polymerization of n-butyraldehyde. Eur.Polym. J. 2017, 93, 97-102.
38 Zhao, N.; Ren, C. L.; Li,H. K.; Li, Y. X.; Liu,S. F.; Li, Z.B.Selective ring-opening polymerization of non-strained y-butyrolactone catalyzed by a cyclic trimeric phosphazene base. Angew.Chem. Int. Ed. 2017, 56, 12987-12990.
39 Li, H. K.; Zhao, N.; Ren, C. L.; Liu, S. F.; Li, Z. B. Synthesis of linear and star poly(ε-caprolactone)with controlled and high molecular weights via cyclic trimeric phosphazene base catalyzed ring-opening polymerization. Polym. Chem. 2017, 8,7369-7374.
40 Wang,J.; Li,B. X.; Xin,D. H.; Hu, R. R.; Zhao, Z. J.; Qin,A.J.; Tang, B. Z. Superbase catalyzed regio-selective polyhydroalkoxylation of alkynes:A facile route towards functional poly(vinyl ether)s. Polym. Chem. 2017, 8, 2713-2722.
41 Fevre, M. Tris(2,4,6-trimethoxyphenyl)phosphine(TTMPP)as potent organocatalyst for group transfer polymerization of alkyl(meth)acrylates. Macromolecules 2012, 45, 7711-7718.
42 Wang, D.; Hadjichristidis, N. Allyl borates:A novel class of polyhomologation initiators. Chem. Commun. 2017, 53,1196-1199.
43 Lascelles,S. F.; Malet,F.; Mayada,R.; Billingham,N. C.;Armes, S. P. Latex syntheses using novel tertiary amine methacrylate-based macromonomers prepared by oxyanionic polymerization. Macromolecules 1999, 32, 2462-2471.
44 Yang, H. J.; Xu, J. B.; Pispas, S.; Zhang, G. Hybrid copolymerization ofε-caprolactone and methyl methacrylate. Macromolecules 2012, 45, 3312-3317.
45 Yang, H. J.; Bai, T.; Xue, X. Q.; Huang, W. Y.; Chen, J. H.;Qian, X. L.; Zhang, G. Z.; Jiang, B. B. A versatile strategy for synthesis of hyperbranched polymers with commercially available methacrylate inimer. RSC Adv. 2015, 5, 60401-60408.
46 Yang, H. J.; Bai, T.; Xue, X. Q.; Huang, W. Y.; Chen, J. H.;Qian, X. L.; Zhang, G. Z.; Jiang, B. B. A simple route to vinylfunctionalized hyperbranched polymers:Self-condensing anionic copolymerization of allyl methacrylate and hydroxyethyl methacrylate. Polymer 2015, 72, 63-68.
47 Zhang,Y. T.; Schmitt.M.; Falivene,L.; Caporaso, L.; Cavallo,L.; Chen, E. Y. X. Organocatalytic conjugate-addition polymerization of linear and cyclic acrylic monomers by N-heterocyclic carbenes:Mechanisms of chain initiation, propagation, and termination. J. Am. Chem. Soc. 2013,135, 17925-17942.
48 Odian, G. in Principles of Polymerization, 4th Ed., John Wiley&Sons,Hoboken,NJ,USA,2004.
2 Schwesinger, R.; Willaredt, J.; Schlemper, H.; Keller, M.;Schmitt, D.; Fritz, H. Novel, very strong, uncharged auxiliary bases; design and synthesis of monomeric and polymer-bound triaminoiminophosphorane bases of broadly varied steric demand. Chem. Ber. 1994,127, 2435-2454.
3 Schwesinger,R.; Schlemper,H.; Hasenfratz,C.; Willaredt, J.;Dambacher,T.; Breuer,T.; Ottaway,C.; Fletschinger, M.;Boele,J.; Fritz,H.; Putzas,D.; Rotter,H. W.; Bordwell,F. G.;Satish, A. V.; Ji, G. Z.; Peters, E. M.; Peters, K.; Schnering, H.G. V.; Walz, L. Extremely strong, uncharged auxiliary bases;monomeric and polymer-supported polyaminophosphazenes(P2-P5).Liebigs Ann. 1996, 7, 1055-1081.
4 Kaupmees,K.; Trummal,A.; Leito, I. Basicities of strong basesin water:A computational study. Croat. Chem. Acta 2014, 87,385-395.
5 Pietzonka,T.; Seebach,D. Alkylations of(R,R)-2-t-butyl-6-methyl-1,3-dioxan-4-ones which are not possible with lithium amides may be achieved with a schwesinger P4 Base. Chem.Ber. 1991,124, 1837-1843.
6 Pietzonka, T.; Seebach, D. N-Perbenzylation of oligopeptides with P4-phosphazene base; a new protecting-group technique for modification and solubilization of peptides in apolar organic solvents.Angew. Chem. Int. Ed. 1992, 31, 1481-1482.
7 Pietzonka, T.; Seebach, D. The P4-phosphazene base as part of a new metal-free initiator system for the anionic polymerization of methyl methacrylate. Angew. Chem. Int. Ed. 1993, 32,716-717.
8 Isono, T. Synthesis of star-and figure-eight-shaped polyethers by t-Bu-P4-catalyzed ring-opening polymerization of butylene oxide. Macromolecules 2013, 46, 3841-3849.
9 Song, Q. L.; Hu,S. Y.; Zhao, J. P.; Zhang,G. Z. Organocatalytic copolymerization of mixed type monomers. Chinese J.Polym. Sci. 2017, 35, 581-601.
10 Kondo, Y. in Superbases for organic synthesis:Guanidines,amidines,phosphazenes and related organocatalysts, John Wiley&Sons Ltd.,2009, pp. 145-185.
11 Boileau, S.; Illy, N. Activation in anionic polymerization:Why phosphazene bases are very exciting promoters.Prog.Polym.Sci. 2011,36, 1132-1151.
12 Ottou,W. N.; Sardon,H.; Mecerreyes,D.; Vignolle,J.; Taton,D. Update and challenges in organo-mediated polymerization reactions. Prog. Polym. Sci. 2016, 56, 64-115.
13 Hui S. Y.; Zhao, J. P.; Zhang, G. Z.; Schlaad, H. Macromolecular architectures through organocatalysis. Prog. Polym. Sci.2017, 74, 34-77.
14 Hong, M.; Chen, E. Y. X. Towards truly sustainable polymers:A metal-free recyclable polyester from biorenewable nonstrained y-butyrolactone. Angew. Chem. Int. Ed. 2016,55,4188-4193.
15 Hong,M.; Tang,X. Y.; Newell,B. S.; Chen,E. Y. X."Nonstrained"y-butyrolactone-based copolyesters:Copolymerization characteristics and composition-dependent(thermal, eutectic, cocrystallization, and degradation)properties. Macromolecules 2017, 50, 8469-8479.
16 Song,Q. L.; Xia,Y. N.; Hu,S. Y.; Zhao, J. P.; Zhang,G. Z.Tuning the crystallinity and degradability of PCL by organocatalytic copolymerization withδ-hexalactone. Polymer2016,102, 248-255.
17 Zhang,L.; Nederberg,F.; Messman,J. M.; Pratt,R. C.;Hedrick, J. L.; Wade, C. G. Organocatalytic stereoselective ring-opening polymerization of lactide with dimeric phosphazene bases. J. Am. Chem. Soc. 2007,129, 12610-12611.
18 Liu, J. J.; Chen, C.; Li, Z. J.; Wu, W. Z.; Zhi, X.; Zhang, Q. G.;Wu, H.; Wang, X.; Cui, S. D.; Guo, K. A squaramide and tertiary amine:An excellent hydrogen-bonding pair organocatalyst for living polymerization. Polym. Chem. 2015,6,3754-3757.
19 Liu, S. F.; Ren, C. L.; Zhao, N.; Shen, Y.; Li, Z. B. Phosphazene bases as organocatalysts for ring-opening polymerization of cyclic esters. Macromol. Rapid Commun. 2018, 39,1800485.
20 Li,Y. X.; Zhao, N.; Wei, C. Z.; Sun, A. B.; Liu,S. F.; Li,Z. B.Binary organocatalytic system for ring-opening polymerization ofε-caprolactone andδ-valerolactone:Synergetic effects for enhanced selectivity. Eur. Polym. J. 2019, 111, 11-19.
21 Liu, S. F.; Li, H. K.; Zhao, N.; Li, Z. B. Stereoselective ringopening polymerization of rac-lactide using organocatalytic cyclic trimeric phosphazene base. ACS Macro Lett. 2018, 7,624-628.
22 Dentzer, L.; Bray, C.; Noinville, S.; Illy, N.; Guegan, P. Phosphazene-promoted metal-free ring-opening polymerization of1,2-epoxybutane initiated by secondary amides. Macromolecules 2015, 48, 7755-7764.
23 Hassouna, L.; Illy, N.; Guegan, P. Phosphazene/triisobutylaluminum-promoted anionic ring-opening polymerization of 1,2-epoxybutane initiated by secondary carbamates. Polym. Chem.2017, 8, 4005-4013.
24 Zhang, H. X.; Hu, S. Y.; Zhao, J. P.; Zhang, G. Z. Phosphazene-catalyzed alternating copolymerization of dihydrocoumarin and ethylene oxide:Weaker is better. Macromolecules2017, 50,4198-4205.
25 Zhang,J.;Liu,Q.;Ren,H.J.;Zhang,N.J.;Li,P.F.;Yang,K.Phosphoniums as catalysts for metal-free polymerization:Synthesis of well-defined poly(propylene oxide). J. Mol Struc.2017, 1148, 421-428.
26 Xia, Y. N.; Zhao, J. P. Macromolecular architectures based on organocatalytic ring-opening(co)polymerization of epoxides.Polymer 2018, 143, 343-361.
27 EBwein, B.; Molenberg, A.; Moller, M. Use of polyiminophosphazene bases for ring-opening polymerizations. Macromol.Symp. 1996, 107, 331-340.
28 Molenberg, A.; Moller, M. A fast catalyst system for the ringopening polymerization of cyclosiloxanes. Macromol.Rapid Commun. 1995, 16, 449-453.
29 Pibre, G.; Chaumont, P.; Fleury, E.; Cassagnau, P. Ring-opening polymerization of decamethylcyclopentasiloxane initiated by a superbase:Kinetics and rheology. Polymer 2008, 49,234-240.
30 Dyke, M. E. V.; Clarson, S. J. Reaction kinetics for the anionic ring-opening polymerization of tetraphenyltetramethylcyclotetrasiloxane using a fast initiator system. J. Inorg. Organomet.Polym. 1998, 8, 111-117.
31 Samuel,C.; Chalamet,Y.; Boisson,F.; Majeste, J.; Becquart,F.; Fleury, E. Highly efficient metal-free organic catalysts to design new environmentally friendly starch-based blends. J.Polym. Sci., Part A:Polym. Chem. 2014, 52, 493-503.
32 Brignou, P.; Gil, M. P.; Casagrande, O.; Carpentier, J. F.; Guillaume, S. M. Polycarbonates derived from green acids:Ringopening polymerization of seven-membered cyclic carbonates.Macromolecules 2010, 43, 8007-8017.
33 Chen, J. L.; Li, M. S.; He, W. J.; Tao, Y. H.; Wang, X. H. Facile organocatalyzed synthesis of poly(ε-lysine)under mild conditions. Macromolecules 2017, 50, 9128-9134.
34 Jr, W. M.; Campbell, G. C.; Davidson, F. Poly(aminophosphazene)s and protophosphatranes mimic classical strong anionic base catalysts in the anionic ring-opening polymerization of lactams.Macromolecules 1996, 29, 6475-6480.
35 Borner, H. G.; Heitz, W. Anionic polymerization of butyl acrylate with metal free initiator systems containing[1-tert-butyl-4,4,4-tris(dimethylamino)-2,2-bis[tris(dimethylamino)-phosphor-anylidenamino]-2λ5,4λ5-catenadi(phosphazene)] base(P4-tert-butyl-phosphazene base). Macromol. Chem. Phys. 1998,199, 1815-1820.
36 Kakuchi, T.; Chen,Y.; Kitakado,J.; Mori, K.; Fuchise,K.;Satoh, T. Organic superbase as an efficient catalyst for group transfer polymerization of methyl methacrylate. Macromolec ules 2011,44, 4641-4647.
37 Weideman,I.; Pfukwa,R.; Klumperman,B. Phosphazene base promoted anionic polymerization of n-butyraldehyde. Eur.Polym. J. 2017, 93, 97-102.
38 Zhao, N.; Ren, C. L.; Li,H. K.; Li, Y. X.; Liu,S. F.; Li, Z.B.Selective ring-opening polymerization of non-strained y-butyrolactone catalyzed by a cyclic trimeric phosphazene base. Angew.Chem. Int. Ed. 2017, 56, 12987-12990.
39 Li, H. K.; Zhao, N.; Ren, C. L.; Liu, S. F.; Li, Z. B. Synthesis of linear and star poly(ε-caprolactone)with controlled and high molecular weights via cyclic trimeric phosphazene base catalyzed ring-opening polymerization. Polym. Chem. 2017, 8,7369-7374.
40 Wang,J.; Li,B. X.; Xin,D. H.; Hu, R. R.; Zhao, Z. J.; Qin,A.J.; Tang, B. Z. Superbase catalyzed regio-selective polyhydroalkoxylation of alkynes:A facile route towards functional poly(vinyl ether)s. Polym. Chem. 2017, 8, 2713-2722.
41 Fevre, M. Tris(2,4,6-trimethoxyphenyl)phosphine(TTMPP)as potent organocatalyst for group transfer polymerization of alkyl(meth)acrylates. Macromolecules 2012, 45, 7711-7718.
42 Wang, D.; Hadjichristidis, N. Allyl borates:A novel class of polyhomologation initiators. Chem. Commun. 2017, 53,1196-1199.
43 Lascelles,S. F.; Malet,F.; Mayada,R.; Billingham,N. C.;Armes, S. P. Latex syntheses using novel tertiary amine methacrylate-based macromonomers prepared by oxyanionic polymerization. Macromolecules 1999, 32, 2462-2471.
44 Yang, H. J.; Xu, J. B.; Pispas, S.; Zhang, G. Hybrid copolymerization ofε-caprolactone and methyl methacrylate. Macromolecules 2012, 45, 3312-3317.
45 Yang, H. J.; Bai, T.; Xue, X. Q.; Huang, W. Y.; Chen, J. H.;Qian, X. L.; Zhang, G. Z.; Jiang, B. B. A versatile strategy for synthesis of hyperbranched polymers with commercially available methacrylate inimer. RSC Adv. 2015, 5, 60401-60408.
46 Yang, H. J.; Bai, T.; Xue, X. Q.; Huang, W. Y.; Chen, J. H.;Qian, X. L.; Zhang, G. Z.; Jiang, B. B. A simple route to vinylfunctionalized hyperbranched polymers:Self-condensing anionic copolymerization of allyl methacrylate and hydroxyethyl methacrylate. Polymer 2015, 72, 63-68.
47 Zhang,Y. T.; Schmitt.M.; Falivene,L.; Caporaso, L.; Cavallo,L.; Chen, E. Y. X. Organocatalytic conjugate-addition polymerization of linear and cyclic acrylic monomers by N-heterocyclic carbenes:Mechanisms of chain initiation, propagation, and termination. J. Am. Chem. Soc. 2013,135, 17925-17942.
48 Odian, G. in Principles of Polymerization, 4th Ed., John Wiley&Sons,Hoboken,NJ,USA,2004.