Preparation of Ultralow Molecular Weight Poly(vinyl chloride) with Submicrometer Particles via Precipitation Polymerization
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摘要
Poly(vinyl chloride), with ultralow molecular weight, produced by free radical polymerization either at high temperature or in the presence of chain transfer agents, is widely used as special resins and polymer process additives. This paper reports a new process,called self-stabilized precipitation polymerization, in which the polymerization of vinyl chloride monomer(VCM) is conducted in hydrocarbon diluents without addition of any suspending agent or emulsifier. The merits of this novel strategy include:(1) PVC resins with ultra-low number-average molecular weight(Mn) from 4000 to 15000, which is much lower than Mn of those prepared by conventional suspension and emulsion polymerizations,(2) sub-micrometer PVC particles with near spherical morphology, and(3) the very simple post-polymerization separation process. Under mild stirring, polymerization proceeds stably and smoothly. The influences of main process factors, such as solvents, initiator and monomer concentrations, polymerization time, and temperature on both particle morphology and Mn of the polymer products are investigated systematically. The molar ratio of ―CH2―CHCl―/―CH=CH―CH2 CHCl, a good indicator of structural defects, is about 1000/0.1 which means the low molecular weights do not result from chain transfer to the monomers. Then the mechanism of this polymerization is proposed. In summary, this novel polymerization technology provides a straightforward method for preparing PVC particulate products with low Mn.
Poly(vinyl chloride), with ultralow molecular weight, produced by free radical polymerization either at high temperature or in the presence of chain transfer agents, is widely used as special resins and polymer process additives. This paper reports a new process,called self-stabilized precipitation polymerization, in which the polymerization of vinyl chloride monomer(VCM) is conducted in hydrocarbon diluents without addition of any suspending agent or emulsifier. The merits of this novel strategy include:(1) PVC resins with ultra-low number-average molecular weight(Mn) from 4000 to 15000, which is much lower than Mn of those prepared by conventional suspension and emulsion polymerizations,(2) sub-micrometer PVC particles with near spherical morphology, and(3) the very simple post-polymerization separation process. Under mild stirring, polymerization proceeds stably and smoothly. The influences of main process factors, such as solvents, initiator and monomer concentrations, polymerization time, and temperature on both particle morphology and Mn of the polymer products are investigated systematically. The molar ratio of ―CH2―CHCl―/―CH=CH―CH2 CHCl, a good indicator of structural defects, is about 1000/0.1 which means the low molecular weights do not result from chain transfer to the monomers. Then the mechanism of this polymerization is proposed. In summary, this novel polymerization technology provides a straightforward method for preparing PVC particulate products with low Mn.
Poly(vinyl chloride), with ultralow molecular weight, produced by free radical polymerization either at high temperature or in the presence of chain transfer agents, is widely used as special resins and polymer process additives. This paper reports a new process,called self-stabilized precipitation polymerization, in which the polymerization of vinyl chloride monomer(VCM) is conducted in hydrocarbon diluents without addition of any suspending agent or emulsifier. The merits of this novel strategy include:(1) PVC resins with ultra-low number-average molecular weight(Mn) from 4000 to 15000, which is much lower than Mn of those prepared by conventional suspension and emulsion polymerizations,(2) sub-micrometer PVC particles with near spherical morphology, and(3) the very simple post-polymerization separation process. Under mild stirring, polymerization proceeds stably and smoothly. The influences of main process factors, such as solvents, initiator and monomer concentrations, polymerization time, and temperature on both particle morphology and Mn of the polymer products are investigated systematically. The molar ratio of ―CH2―CHCl―/―CH=CH―CH2 CHCl, a good indicator of structural defects, is about 1000/0.1 which means the low molecular weights do not result from chain transfer to the monomers. Then the mechanism of this polymerization is proposed. In summary, this novel polymerization technology provides a straightforward method for preparing PVC particulate products with low Mn.
引文
1 Saeki,Y.;Emura,T.Technical progresses for PVC production.Prog.Polym.Sci.2002,27,2055-2131.
2 Brandrup,J.;Immergut,E.H.Polymer handbook.Wiley,New York,1989.
3 Xu,X.;Guo,S.A study on morphological structure of low molecular weight PVC prepared by vibromilling degradation.Polym.Plast.Technol. Eng.1995,34,621-632.
4 Huang,Z.;Pan,P.;Bao,Y.Z.Solution and aqueous miniemulsion polymerization of vinyl chloride mediated by a fluorinated xanthate.J.Polym.Sci.,Part A:Polym.Chem.2016,54,2092-2101.
5 Abreu,C.M.;Mendonca,P.V.;Serra,A.N.C.;Coelho,J.F.;Popov,A.V.; Gryn'ova,G.; Coote,M.L.;Guliashvili,T.Reversible addition-fragmentation chain transfer polymerization of vinyl chloride.Macromolecules 2012,45,2200-2208.
6 Percec,V.; Popov,A.V.; Ramirez-castillo,E.; Weichold,O.Living radical polymerization of vinyl chloride initiated with iodoform and catalyzed by nascent Cu0/tris(2-aminoethyl)amine or polyethyleneimine in water at 25℃proceeds by a new competing pathways mechanism.J.Polym. Sci.,Part A:Polym.Chem.2003,41,3283-3299.
7 Smallwood,P.The formation of grains of suspension poly(vinyl chloride).Polymer 1986,2 7,1609-1618.
8 Georgiadou,S.; Thomas,N.; Gilbert,M.; Brooks,B.Nonaqueous polymerization of vinyl chloride:An environmentally friendly process.J.Appl. Polym.Sci.2009,112,2472-2481.
9 Balakrishnan,T.; Ford,W.T.Particle size control in suspension copolymerization of styrene,chloromethylstyrene,and divinylbenzene.J.Appl.Polym.Sci. 1982,27,133-138.
10 Negre,M.; Bartholin,M.; Guyot,A.Functionalized resins,1.Gel and macroporous chloromethylated styrenic resins prepared in the presence of toluene as a pore forming agent.Die Angew.Makromol.Chem.1982,106,67-77.
11 Chonde,Y.; Liu,L.J.; Krieger,I.M.Preparation and surface modification of poly(vinylbenzyl chloride)latices.J.Appl.Polym.Sci. 1980,25,2407-2416.
12 Prince,K.Water dilutable secondary stabilisers in suspension polymerisation of vinyl chloride monomer.Plast Rubber Compos.1999,28,105-108.
13 Sperling,L.H.Introduction to physical polymer science.John Wiley&Sons,2005.
14 Machleidt,R.,The meson theory of nuclear forces and nuclear structure,in Advances in nuclear physics,Vol 19,ed.by Negele,J.W.; Vogt,E.Springer,Boston,MA,1989,p.189-376.
15 Bao,Y.; Brooks,B.Particle features of poly(vinyl chloride)resins prepared by a new heterogeneous polymerization process.J.Appl. Polym.Sci.2003,90,954-958.
16 Butters,G.Particulate nature of PVC:Formation,structure and processing.Applied Science Publishers,1982.
17 Xie,T.; Hamielec,A.;Wood,P.;Woods,D.Suspension,bulk,and emulsion polymerization of vinyl chloride-mechanism,kinetics,and reactor modelling.J.Vinyl Technol. 1991,13,2-25.
18 Yuan,H.; Kalfas,G.; Ray,W.Suspension polymerization.J.Macromol. Sci.,Part C:Polym.Rev.1991,31,215-299.
19 Cebollada,A.; Schmidt,M.; Farber,J.; Capiati,N.; Valles,E.Suspension polymerization of vinyl chloride.I.Influence of viscosity of suspension medium on resin properties.J.Appl.Polym.Sci. 1989,3 7,145-166.
20 Freidlina,R.K.;Velichko,F.;Zlotskii,S.;Rakhmankulov,D.;Terent'ev,A.B.Radical telomerization.Khimiya,Moscow,1988.
21 Mickley,H.S.;Michaels,A.S.;Moore,A.L.Kinetics of precipitation polymerization of vinyl chloride.J.Polym.Sci.1962,60,121-140.
22 Kronman,A.; Groshev,G.; Leshina,L.; Sitnikova,E.; Sulina,T.Polymerization of vinyl chloride in the presence of alcohols.Russian J.AppL Chem.2001,74,1007-1009.
23 Xing,C.M.;Yang,W.T.A novel,facile method for the preparation of uniform,reactive maleic anhydride/vinyl acetate copolymer micro-and nanospheres.Macromol. Rapid Commun.2004,25,1568-1574.
24 Xing,C.M.;Yang,W.T.Stabilizer-free dispersion copolymerization of maleic anhydride and vinyl acetate.Ⅰ.Effects of principal factors on microspheres.J.Polym.Sci., Part A:Polym.Chem.2005, 43,3760-3770.
25 Xing,C.M.;Yu,Y.;Yang,W.T.Stabilizer-free dispersion copolymerization of maleic anhydride and vinyl acetate.Ⅱ.Polymerization features.Macromol. Chem.Phys.2006,207,621-626.
26 Liu,Z.J.;Chen,D.;Zhang,J.F.;Liao,H.D.;Chen,Y.Z.;Sun,Y.F.; Deng,J.Y.; Yang,W.T.Self-stabilized precipitation polymerization and its application.Research 2018,2018,9370490.
27 Luo,W.;Liu,J.X.;Ma,Y.H.;Zhang,B.;Yang,W.T.Preparation of polymer nanoparticles from renewable biobased furfuryl alcohol and maleic anhydride by stabilizer-free dispersion polymerization.J.Polym.Sci., Part A:Polym.Chem.2012,50,3606-3617.
28 Ramram,M.B.;Chen,D.;Ma,Y.;Wang,L.;Yang,W.Stabilizer-free precipitation copolymerization of renewable bio-based a-methylene-y-butyrolactone and styrene.J.Macromol. Sci.,Part A 2016,53,484-491.
29 Barclay,L.Formation and structure of PVC particles.Angew.Makromol.Chem.:Appl.Macromol.Chem.Phys.1976,52,1-20.
30 Tseng,C.M.; Lu,Y.Y.;El-Aasser,M.S.;Vanderhoff,J.W.Uniform polymer particles by dispersion polymerization in alcohol.J.Polym.Sci., Part A:Polym.Chem.1986,24,2995-3007.
31 Thomson,B.; Rudin,A.; Lajoie,G.Dispersion copolymerization of styrene and divinylbenzene:Synthesis of monodisperse,uniformly crosslinked particles.J.Polym.Sci., Part A.Polym.Chem.1995,33,345-357.
32 Zhang,F.; Bai,Y.W.; Ma,Y.H.; Yang,W.T.Preparing ofmonodisperse and cation-charged polystyrene particles stabilized with polymerizable quarternary ammonium by dispersion polymerization in a methanol-water medium.J.Colloid Interf.Sci.2009,334,13-21.
33 Yan,Q.;Bai,Y.W.;Meng,Z.;Yang,W.T.Precipitation polymerization in acetic acid:Synthesis of monodisperse crosslinked poly(divinyl benzene)microspheres.J.Phys.Chem.B2008,112,6914-6922.
34 Chatelain,J.Two stage bulk polymerisation process of vinyl chloride.British Polym.J.1973,5,457-465.
35 Bao,Y.Z.; Brooks,B.W.Phaseequilibrium behavior of vinyl chloride/nbutane and its application in determination of vinyl chloride heterogeneous polymerization kinetics.J.Polym.Sci.,Part A:Polym.Chem.2001,39,2179-2188.
36 Bao,Y.Z.; Brooks,B.W.Influences of some polymerization conditions on particle properties of suspension poly(vinyl chloride)resin.J.Appl. Polym.Sci.2002,85,1544-1552.
37 Abreu,C.M.R.;Mendonga,P.V.;Serra,A.C.;Noble,B.B.;Guliashvili,T.; Nicolas,J.; Coote,M.L.; Coelho,J.F.J.Nitroxide-mediated polymerization of vinyl chloride at low temperature:Kinetic and computational studies.Macromolecules2016,49,490-498.
38 Hansen,. K.; Ugelstad,J. Particle nucleation in emulsion polymerization.Ⅱ.Nucleation in emulsifier-free systems investigated by seed polymerization.J.Polym.Sci.,Part A:Polym.Chem.1979,17,3033-3045.
39 Goodall,A. R.; Wilkinson,M.C.; Hearn,J.Mechanism of emulsion polymerization of styrene in soap-free systems.J.Polym.Sci.,Part A:Polym.Chem.1977,15,2193-2218.
40 Hansen,F. K.; Ugelstad,J. Particle nucleation in emulsion polymerization.I.A theory for homogeneous nucleation.J.Polym.Sci.,Part A:Polym.Chem.1978,16,1953-1979.
41 Shen,S.;Sudol,E.D.;El-Aasser,M.S.Dispersion polymerization of methyl methacrylate:Mechanism of particle formation.J.Polym.Sci., Part A:Polym.Chem.1994,32,1087-1100.
42 Xu, J.;Jung,K.;Boyer,C.Oxygen tolerance study of photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization mediated by Ru(bpy)Cl2.Macromolecules 2014,47,4217-4229.
2 Brandrup,J.;Immergut,E.H.Polymer handbook.Wiley,New York,1989.
3 Xu,X.;Guo,S.A study on morphological structure of low molecular weight PVC prepared by vibromilling degradation.Polym.Plast.Technol. Eng.1995,34,621-632.
4 Huang,Z.;Pan,P.;Bao,Y.Z.Solution and aqueous miniemulsion polymerization of vinyl chloride mediated by a fluorinated xanthate.J.Polym.Sci.,Part A:Polym.Chem.2016,54,2092-2101.
5 Abreu,C.M.;Mendonca,P.V.;Serra,A.N.C.;Coelho,J.F.;Popov,A.V.; Gryn'ova,G.; Coote,M.L.;Guliashvili,T.Reversible addition-fragmentation chain transfer polymerization of vinyl chloride.Macromolecules 2012,45,2200-2208.
6 Percec,V.; Popov,A.V.; Ramirez-castillo,E.; Weichold,O.Living radical polymerization of vinyl chloride initiated with iodoform and catalyzed by nascent Cu0/tris(2-aminoethyl)amine or polyethyleneimine in water at 25℃proceeds by a new competing pathways mechanism.J.Polym. Sci.,Part A:Polym.Chem.2003,41,3283-3299.
7 Smallwood,P.The formation of grains of suspension poly(vinyl chloride).Polymer 1986,2 7,1609-1618.
8 Georgiadou,S.; Thomas,N.; Gilbert,M.; Brooks,B.Nonaqueous polymerization of vinyl chloride:An environmentally friendly process.J.Appl. Polym.Sci.2009,112,2472-2481.
9 Balakrishnan,T.; Ford,W.T.Particle size control in suspension copolymerization of styrene,chloromethylstyrene,and divinylbenzene.J.Appl.Polym.Sci. 1982,27,133-138.
10 Negre,M.; Bartholin,M.; Guyot,A.Functionalized resins,1.Gel and macroporous chloromethylated styrenic resins prepared in the presence of toluene as a pore forming agent.Die Angew.Makromol.Chem.1982,106,67-77.
11 Chonde,Y.; Liu,L.J.; Krieger,I.M.Preparation and surface modification of poly(vinylbenzyl chloride)latices.J.Appl.Polym.Sci. 1980,25,2407-2416.
12 Prince,K.Water dilutable secondary stabilisers in suspension polymerisation of vinyl chloride monomer.Plast Rubber Compos.1999,28,105-108.
13 Sperling,L.H.Introduction to physical polymer science.John Wiley&Sons,2005.
14 Machleidt,R.,The meson theory of nuclear forces and nuclear structure,in Advances in nuclear physics,Vol 19,ed.by Negele,J.W.; Vogt,E.Springer,Boston,MA,1989,p.189-376.
15 Bao,Y.; Brooks,B.Particle features of poly(vinyl chloride)resins prepared by a new heterogeneous polymerization process.J.Appl. Polym.Sci.2003,90,954-958.
16 Butters,G.Particulate nature of PVC:Formation,structure and processing.Applied Science Publishers,1982.
17 Xie,T.; Hamielec,A.;Wood,P.;Woods,D.Suspension,bulk,and emulsion polymerization of vinyl chloride-mechanism,kinetics,and reactor modelling.J.Vinyl Technol. 1991,13,2-25.
18 Yuan,H.; Kalfas,G.; Ray,W.Suspension polymerization.J.Macromol. Sci.,Part C:Polym.Rev.1991,31,215-299.
19 Cebollada,A.; Schmidt,M.; Farber,J.; Capiati,N.; Valles,E.Suspension polymerization of vinyl chloride.I.Influence of viscosity of suspension medium on resin properties.J.Appl.Polym.Sci. 1989,3 7,145-166.
20 Freidlina,R.K.;Velichko,F.;Zlotskii,S.;Rakhmankulov,D.;Terent'ev,A.B.Radical telomerization.Khimiya,Moscow,1988.
21 Mickley,H.S.;Michaels,A.S.;Moore,A.L.Kinetics of precipitation polymerization of vinyl chloride.J.Polym.Sci.1962,60,121-140.
22 Kronman,A.; Groshev,G.; Leshina,L.; Sitnikova,E.; Sulina,T.Polymerization of vinyl chloride in the presence of alcohols.Russian J.AppL Chem.2001,74,1007-1009.
23 Xing,C.M.;Yang,W.T.A novel,facile method for the preparation of uniform,reactive maleic anhydride/vinyl acetate copolymer micro-and nanospheres.Macromol. Rapid Commun.2004,25,1568-1574.
24 Xing,C.M.;Yang,W.T.Stabilizer-free dispersion copolymerization of maleic anhydride and vinyl acetate.Ⅰ.Effects of principal factors on microspheres.J.Polym.Sci., Part A:Polym.Chem.2005, 43,3760-3770.
25 Xing,C.M.;Yu,Y.;Yang,W.T.Stabilizer-free dispersion copolymerization of maleic anhydride and vinyl acetate.Ⅱ.Polymerization features.Macromol. Chem.Phys.2006,207,621-626.
26 Liu,Z.J.;Chen,D.;Zhang,J.F.;Liao,H.D.;Chen,Y.Z.;Sun,Y.F.; Deng,J.Y.; Yang,W.T.Self-stabilized precipitation polymerization and its application.Research 2018,2018,9370490.
27 Luo,W.;Liu,J.X.;Ma,Y.H.;Zhang,B.;Yang,W.T.Preparation of polymer nanoparticles from renewable biobased furfuryl alcohol and maleic anhydride by stabilizer-free dispersion polymerization.J.Polym.Sci., Part A:Polym.Chem.2012,50,3606-3617.
28 Ramram,M.B.;Chen,D.;Ma,Y.;Wang,L.;Yang,W.Stabilizer-free precipitation copolymerization of renewable bio-based a-methylene-y-butyrolactone and styrene.J.Macromol. Sci.,Part A 2016,53,484-491.
29 Barclay,L.Formation and structure of PVC particles.Angew.Makromol.Chem.:Appl.Macromol.Chem.Phys.1976,52,1-20.
30 Tseng,C.M.; Lu,Y.Y.;El-Aasser,M.S.;Vanderhoff,J.W.Uniform polymer particles by dispersion polymerization in alcohol.J.Polym.Sci., Part A:Polym.Chem.1986,24,2995-3007.
31 Thomson,B.; Rudin,A.; Lajoie,G.Dispersion copolymerization of styrene and divinylbenzene:Synthesis of monodisperse,uniformly crosslinked particles.J.Polym.Sci., Part A.Polym.Chem.1995,33,345-357.
32 Zhang,F.; Bai,Y.W.; Ma,Y.H.; Yang,W.T.Preparing ofmonodisperse and cation-charged polystyrene particles stabilized with polymerizable quarternary ammonium by dispersion polymerization in a methanol-water medium.J.Colloid Interf.Sci.2009,334,13-21.
33 Yan,Q.;Bai,Y.W.;Meng,Z.;Yang,W.T.Precipitation polymerization in acetic acid:Synthesis of monodisperse crosslinked poly(divinyl benzene)microspheres.J.Phys.Chem.B2008,112,6914-6922.
34 Chatelain,J.Two stage bulk polymerisation process of vinyl chloride.British Polym.J.1973,5,457-465.
35 Bao,Y.Z.; Brooks,B.W.Phaseequilibrium behavior of vinyl chloride/nbutane and its application in determination of vinyl chloride heterogeneous polymerization kinetics.J.Polym.Sci.,Part A:Polym.Chem.2001,39,2179-2188.
36 Bao,Y.Z.; Brooks,B.W.Influences of some polymerization conditions on particle properties of suspension poly(vinyl chloride)resin.J.Appl. Polym.Sci.2002,85,1544-1552.
37 Abreu,C.M.R.;Mendonga,P.V.;Serra,A.C.;Noble,B.B.;Guliashvili,T.; Nicolas,J.; Coote,M.L.; Coelho,J.F.J.Nitroxide-mediated polymerization of vinyl chloride at low temperature:Kinetic and computational studies.Macromolecules2016,49,490-498.
38 Hansen,. K.; Ugelstad,J. Particle nucleation in emulsion polymerization.Ⅱ.Nucleation in emulsifier-free systems investigated by seed polymerization.J.Polym.Sci.,Part A:Polym.Chem.1979,17,3033-3045.
39 Goodall,A. R.; Wilkinson,M.C.; Hearn,J.Mechanism of emulsion polymerization of styrene in soap-free systems.J.Polym.Sci.,Part A:Polym.Chem.1977,15,2193-2218.
40 Hansen,F. K.; Ugelstad,J. Particle nucleation in emulsion polymerization.I.A theory for homogeneous nucleation.J.Polym.Sci.,Part A:Polym.Chem.1978,16,1953-1979.
41 Shen,S.;Sudol,E.D.;El-Aasser,M.S.Dispersion polymerization of methyl methacrylate:Mechanism of particle formation.J.Polym.Sci., Part A:Polym.Chem.1994,32,1087-1100.
42 Xu, J.;Jung,K.;Boyer,C.Oxygen tolerance study of photoinduced electron transfer-reversible addition-fragmentation chain transfer(PET-RAFT)polymerization mediated by Ru(bpy)Cl2.Macromolecules 2014,47,4217-4229.