Macromolecules 2007, 40, 9313-9321
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Synthesis, Characterization, and Functionalization of Hyperbranched Poly(3,4-epoxycyclohexanemethanol) Yoshikazu Kitajyo,† Yuki Kinugawa,† Masaki Tamaki,† Harumi Kaga,‡ Noriaki Kaneko,§ Toshifumi Satoh,*,⊥,† and Toyoji Kakuchi† DiVision of Biotechnology and Macromolecular Chemistry, Graduate School of Engineering, Hokkaido UniVersity, Sapporo 060-8628, Japan; National Institute of AdVanced Industrial Science and Technology (AIST), 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan; MACROTEC Company, 2-17-2-1 Tsukisamu-Higashi, Toyohira-ku, Sapporo 062-8517, Japan; and DiVision of InnoVatiVe Research, CreatiVe Research InitiatiVe “Sousei” (CRIS), Hokkaido UniVersity, Sapporo 001-0021, Japan ReceiVed August 6, 2007; ReVised Manuscript ReceiVed September 19, 2007
ABSTRACT: The cationic ring-opening polymerizations of an alicyclic epoxyalcohol, 3,4-epoxycyclohexanemethanol (1), were carried out using boron trifluoride diethyletherate (BF3‚OEt2) as a catalyst. Polymerization of 1 heterogeneously proceeded to yield a gel-free polymer (poly-1). On the basis of the 13C NMR measurement, poly-1 was a hyperbranched polymer with numerous terminal units, and the degrees of branching (DBs) of poly-1 were in the range from 0.36 to 0.42. The three-dimensional property of poly-1 was investigated by comparison to the physical property of a linear poly(3,4-epoxycyclohexanemethanol) (poly-3). The viscosity and MarkHouwink exponent R of poly-1 were much lower than those of poly-3, suggesting that poly-1 had a compact conformation in solution. In addition, the glass-transition temperature (Tg) of poly-1 was ca. 105 °C, which was also lower than that of poly-3. A novel amphiphilic dendritic polymer (poly-1ASP) having a hydrophobic poly-1 core and hydrophilic L-aspartic acid shell was synthesized. On the basis of the results of an encapsulation experiment, poly-1ASP possessed an encapsulation property for hydrophobic molecule (Reichardt’s dye) in water. Scheme 1
Introduction Three-dimensional macromolecular architectures have attracted much attention because they exhibit unusual physical properties, e.g., a higher solubility and lower viscosity in solution and the molten state, when compared to conventional linear polymers. In particular, hyperbranched polymers with an irregular branching structure, though they are conveniently prepared via the one-pot polymerization of the ABx-type monomer, have characteristics similar to dendrimers as the perfectly branched monodispersed molecules. Therefore, the property and synthetic advantage of hyperbranched polymers provides the possibility of industrial use as a key material in nanotechnology.1-8 Since Kim and Webster reported that hyperbranched polyphenylene was synthesized by the polycondensation of (3,5-dibromophenyl)boronic acid,9,10 there have been various studies on the design and synthesis of hyperbranched polymers. For example, Matyjaszewski and co-workers synthesized a hyperbranched poly(acrylate) by the atom transfer radical polymerization of 2-(2-bromopropionyloxy)ethyl acrylate as an AB*-type monomer.11-14 In addition, Fre´chet,15,16 Matyjaszewski,17,18 and Ishizu19-21 reported the synthesis of hyperbranched polystyrene by the self-condensing vinyl polymerization of the styrene derivatives and the lower intrinsic viscosity of the polymer relative to linear polystyrene. Of the several synthetic methods of producing a hyperbranched polymer, a ring-opening multibranching polymerization (ROMBP) of epoxy alcohols is a versatile method for * To whom correspondence should be addressed. E-mail: satoh@ poly-bm.eng.hokudai.ac.jp. † Graduate School of Engineering, Hokkaido University. ‡ AIST. § MACROTEC Co. ⊥ CRIS, Hokkaido University.
synthesizing hyperbranched polyethers due to the high reactivity and polymerizability of the epoxy group. For example, Penczek and Dworak et al. reported that glycidol, which is a commercially available and cheap epoxy alcohol, was polymerized by the cationic ring-opening polymerization to yield a watersoluble highly branched polyglycerol.22,23 Frey et al. reported the controlled synthesis of a hyperbranched polyglycerol by the anionic ring-opening polymerization of glycidol using slowmonomer addition techniques.24 Recently, we also proposed that the ROMBP of epoxy alcohol monomers was a facile method for synthesizing the family of hyperbranched carbohydrate polymers, e.g., a hyperbranched poly(2,5-anhydro-D-glucitol),25 and hyperbranched polytetritols.26 Epoxy alcohols are easily prepared by reactions, such as the oxidation of alkenyl alcohol; thus, it is important to polymerize a series of epoxy alcohols
10.1021/ma071756m CCC: $37.00 © 2007 American Chemical Society Published on Web 11/21/2007
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and elucidate the characteristic properties. A paper concerning the polymerizations of various alicyclic epoxyalcohols, which are highly reactive monomers with a highly strained epoxycyclohexane system,27 has been published by Crivello et al.28 However, characterization of the branching structure, solution property, and thermal property of the obtained polymer along with their three-dimensional structure have not yet been reported. We now report the cationic ring-opening polymerization of several alicyclic epoxyalcohols, 3,4-epoxycyclohexanemethanol (1) and R-terpineol epoxide (2), using boron trifluoride diethyletherate (BF3‚OEt2) as a catalyst leading to hydrophobic hyperbranched polymers (poly-1 and poly-2), as shown in Scheme 1. The three-dimensional property of poly-1 was elucidated in conjunction with its branching structure, viscosity, and thermal property and compared to a corresponding linear analog, poly(3,4-epoxycyclohexanemethanol) (poly-3). In addition, a novel water-soluble amphiphilic polymer with hydrophobic poly-1 as a core (poly-1ASP) was synthesized via the carbamation reaction of poly-1 with N-carbonyl L-aspartic acid diethyl ester followed by de-esterification using potassium trimethylsilanolate. The molecular encapsulation property of poly-1ASP was examined using a water-insoluble guest molecule, Reichardt’s dye (RCD), to investigate the performance of poly-1ASP as the molecular nanocarrier. Experimental Section Materials. 3,4-Epoxycyclohexanemethanol (1) and R-terpineol epoxide (2) were synthesized from 3-cyclohexene-1-methanol (98%, Sigma-Aldrich) and R-terpineol (>99.0%, Wako Pure Chemical Industries, Ltd.), respectively, according to a similar method by Pedro et al.29 N-Carbonyl L-aspartic acid diethyl ester was synthesized from L-aspartic acid according to a previous study.30 3,4-Epoxy-1-methoxymethylcyclohexane was synthesized from 1 according to a similar method by Crivello et al.28 tert-Butyldimethylchlorosilane (>97%, Tokyo Kasei Kogyo Co., Ltd.), imidazole (>98%, Kanto Chemical Co., Ltd.), and tetrabutylammonium fluoride (TBAF) (1.0 mol‚L-1 tetrahydrofuran solution, SigmaAldrich) were used as received. Boron trifluoride diethyletherate (BF3‚OEt2) was purchased from Kanto Chemical Co., Ltd. (Tokyo, Japan) and distilled over CaH2 under reduced pressure. Pyridine (>99.0%, Kanto Chemical Co., Ltd.) was distilled over CaH2 just before use. Reichardt’s dye (dye content ) 90%), potassium trimethylsilanolate (90%), and dimethyl sulfoxide anhydrous (dry DMSO) (>99.9%, water content, 99.5%), potassium hydroxide (>85.5%), dry dichloromethane (dry CH2Cl2) (>99.5%; water content, 99.0%), toluene (>99.0%), methanol (>99.5%), acetone (>99.0%), dichloromethane (CH2Cl2) (> 99.0%), hexane (>95.0%), ethyl acetate (>99.0%), and N,N-dimethylformamide (DMF) (>99.0%) were obtained from Kanto Chemical Co., Ltd., and used without further purification. Instrumentation. The 1H NMR and 13C NMR spectra were recorded using a JEOL JNM-A400II instrument. Quantitative 13C NMR spectra were obtained using a 15% (wt/vol) sample in methanol-d4 (CD3OD) at 25 °C, 45° pulse angle, inverse gated decoupling with a 7.0 s delay, 5000 scans, and the solvent peak (δ ) 49.00 ppm) as the internal reference. Preparative SEC for the chloroform-soluble polymers was performed in chloroform (3.5 mL‚min-1) at 23 °C using a JAI LC-9201 equipped with a JAI JAIGEL-3H column (20 mm × 600 mm; exclusion limit, 7 × 104) and a JAI RI-50s refractive index detector. The preparative SEC for the water-soluble polymers was performed in water (14 mL‚min-1) at 23 °C using a JAI LC-928 equipped with a JAI JAIGEL-W253-40 column (40 mm × 500 mm; exclusion limit, 5 × 104) and a JAI RI-50s refractive index detector.
Macromolecules, Vol. 40, No. 26, 2007 The molecular weight value and viscosity of poly-1 were determined by size exclusion chromatography (SEC) in THF (1.0 mL‚min-1) at 40 °C using an Agilent 1100 series instrumentation equipped with two Shodex KF-804L columns (linear, 8 mm × 300 mm; bead size, 7 µm; exclusion limit, 4 × 105), a DAWN 8 multiangle laser light scattering (MALLS) detector (Wyatt Technology, Santa Barbara, CA), a Viscostar viscosity detector (Wyatt Technology), and an Optilab rEX refractive index detector (Wyatt Technology). The absolute molecular weights (Mw,SEC-MALLSs) and intrinsic viscosities ([η]s) were estimated by the software ASTRA 5.1.6.0 (Wyatt Technology). The apparent molecular weights (Mw,SECs) and the polydispersities (Mw/Mns) were calculated on the basis of a polystyrene calibration. The molecular weight values and viscosities of poly-1 and poly-3 were measured by SEC in DMF containing 0.01 M LiBr (0.4 mL‚min-1) at 40 °C using a Agilent 1100 series instrumentation equipped with a Shodex KD-806M column (linear, 8 mm × 300 mm; bead size, 10 µm; exclusion limit, 2 × 107), a DAWN HELEOS MALLS detector (Wyatt Technology), a Viscostar viscosity detector, and an Optilab rEX refractive index detector (Shoko Research Center, Shoko Co., Ltd., Tokyo). The Mw,SEC-MALLSs and [η]s were estimated by the software ASTRA 5.3.1 (Wyatt Technology). Field-ionization mass spectroscopy (FI-MS) of the low molecular weight compounds was performed using a JEOL JMS AX-500 mass spectrometer (GCMS & NMR Laboratory, Graduate School of Agriculture, Hokkaido University). Elemental analysis was performed using a Yanako MT-6 CHN corder (Center for Instrumental Analysis, Hokkaido University). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) of the obtained polymers was performed using an Applied Biosystems Voyager-DE STR-H equipped with a 337 nm-nitrogen laser (3 nm pulse width). Five hundred shots were accumulated for the spectra at a 25 kV acceleration voltage in the reflector mode and calibrated using insulin (TAKARA BIO, Inc.) as the internal standard. Samples for the MALDI-TOF-MS were prepared by mixing the polymer (10 mg‚mL-1, 2 µL), a matrix (2,5-dihydroxybenzoic acid, 10 mg‚mL-1, 20 µL), and a cationizing agent (sodium trifluoroacetate, 10 mg‚mL-1, 2 µL) in methanol. UV-vis spectra were measured at 23 °C in water with a 10mm path length using a Jasco V-550 spectrometer with a deuterium lamp as the light source for the UV range (190-350 nm) and a halogen lamp for the visible range (330-900 nm). Cationic Ring-Opening Polymerizations of 1 and 2. All procedures were performed under an argon atmosphere. A typical procedure for the polymerization (run 3) is as follows: BF3‚OEt2 (12.5 µL, [M]/[cat.] ) 80) was added to a solution of 1 (1.00 g, 7.82 mmol) in dry CH2Cl2 (total volume ) 2.60 mL, 3.0 mol‚L-1) at -5 °C using a microsyringe. After 2 h, the polymerization was terminated by adding methanol containing a small portion of an ammonia aqueous solution. The solution was concentrated under reduced pressure and poured into a large amount of ethyl acetate (300 mL). The precipitated polymer was filtered off and dried in vacuo at 40 °C to give a white solid poly-1. Yield: 0.439 g (44.0%). Mw,SEC (THF) (Mw/Mn) ) 3700 (1.72). Mw,SEC-MALLS (THF) ) 9000. dn/dc (THF) ) 0.1194 mL‚g-1. Mw,SEC-MALLS (DMF) ) 9500. dn/ dc (DMF) ) 0.089 mL‚g-1. 1H NMR (400 MHz, CD3OD): δ 3.95-2.92 (br, H-3, H-4, CH2O, 4H), 2.42-0.77 (br, H-1, H-2, H-5, H-6, 7H). 13C NMR (100 MHz, CD3OD): δ 79.92-75.60 (CH), 74.71 (CH2), 70.42-68.64 (CH), 68.46-67.35 (CH2), 35.47 (3-bonded terminal unit (Ta) and 3,4-bonded linear unit (La), CH), 35.07 (4-bonded terminal unit (Tb), CH), 33.61 (CH), 33.17 (1,3bonded linear unit and 1,4-bonded linear unit (Lb), CH2), 32.78 (Tb, CH2), 32.23-30.39 (br, La, CH2), 30.17 (CH2), 29.78 (CH2), 29.33 (D, CH2), 28.75 (Ta, CH2), 28.61 (Ta, Lb, CH2), 27.76-26.31 (La, CH2), 24.98 (D, CH2), 24.57 (Tb, La, Lb, D, CH2), 24.07 (Ta, CH2). The degrees of branching (DBs) of poly-1 prepared from 1 as an AB2-type monomer were calculated using Frey’s equation (eq 1).31
Macromolecules, Vol. 40, No. 26, 2007 DB )
(
2(Ta + Tb) 2T ) T+L+D Ta + T b + L a + L b + D
Hyperbranched Poly(3,4-epoxycyclohexanemethanol)
)
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Scheme 2
(1)
In the 13C NMR spectra of poly-1 (Figure 1 and S1), the signals at 35.07 and 24.07 ppm were assigned as the C-1 carbon of Tb and the C-6 carbon of Ta, according to the comparison with the chemical shifts of the model compounds 4b and 4a, respectively (Figure S1). In addition, the signals at 35.94-23.67 ppm were also assigned to the C-1, C-2, C-5, and C-6 carbons based on the total units in poly1. Thus, the quantitative 13C NMR spectra of poly-1 were recorded and the (Ta + Tb)/(Ta + Ta + La + Lb + D) values in eq 1 were estimated from the integral ratio of the signals for the terminal units to that for the total units, as shown in eq 2. Ta + Tb ) Ta + T b + L a + L b + D (the signals for Tb and Ta at 35.07 and 24.07 ppm) (2) 1 (the signals for total units at 35.94-23.67 ppm) × 4 The (Ta + Tb)/(Ta + Ta + La + Lb + D) value of poly-1 (run 3) was 0.20. Therefore, the DB value of the polymer was 0.40. 4-Hydroxy-3-methoxy Cyclohexanemethanol (4a) and 3-Hydroxy-4-methoxy Cyclohexanemethanol (4b). BF3‚OEt2 (0.76 mL, 0.2 mol‚L-1) was added to a solution of 1 (0.82 g, 6.4 mmol) in methanol (29 mL) at room temperature. After stirring for 20 h, methanol containing a small portion of an ammonia aqueous solution was added to quench the reaction. The solvent was evaporated, and the residue was purified by column chromatography on silica gel with acetone/dichloromethane (1/1, v/v; Rf ) 0.35) to afford a mixture of 4a and 4b as a colorless liquid. Yield: 0.56 g (54.6%). 1H NMR for 4a (400 MHz, CD3OD): δ 3.66-3.59 (m, H-4, 1H), 3.29 (d, J ) 2.0 Hz, CH2O, 2H), 3.26 (s, CH3, 3H), 3.23-3.15 (m, H-3, 1H), 1.85-1.18 (m, H-1, H-2, H-5, H-6, 7H). 13C NMR for 4a (100 MHz, CD OD): δ 80.51 (C-3), 69.38 (C-4), 3 67.36 (CH2O), 56.81 (CH3), 35.45 (C-1), 28.82 (C-2), 28.53 (C5), 24.09 (C-6). 1H NMR for 4b (400 MHz, CD3OD): δ 3.743.67 (m, H-3, 1H), 3.29 (d, J ) 2.0 Hz, CH2O, 2H), 3.26 (s, CH3, 3H), 3.13-3.06 (m, H-4, 1H), 1.85-1.18 (m, H-1, H-2, H-5, H-6, 7H). 13C NMR for 4b (100 MHz, CD3OD): δ 81.41 (C-4), 68.58 (C-3), 67.36 (CH2O), 56.91 (CH3), 35.16 (C-1), 32.78 (C-2), 24.60 (C-5), 24.34 (C-6). Anal. Calcd for C8H16O3‚2/9H2O (164.2): C, 58.51; H, 10.09. Found: C, 58.55; H, 10.10. FI-MS: m/z (relative intensity): 160 (M+, 100), 161 (MH+, 51.5). 4-Hydroxy-3-methoxy-1-methoxymethyl Cyclohexane (5a) and 3-Hydroxy-4-methoxy-1-methoxymethyl Cyclohexane (5b). BF3‚OEt2 (0.76 mL, 0.2 mol‚L-1) was added to a solution of 3,4epoxy-1-methoxymethylcyclohexane (0.99 g, 6.96 mmol) in methanol (29 mL) at room temperature. After stirring for 5 h, methanol containing a small portion of an ammonia aqueous solution was added to quench the reaction. The solvent was evaporated, and the residue was purified by column chromatography on silica gel with hexane/ethyl acetate (2/3, v/v; Rf ) 0.31) to afford a mixture of 5a and 5b as a colorless liquid. Yield: 0.70 g (57.7%). 1H NMR for 5a (400 MHz, CD3OD): δ 3.74-3.69 (m, H-4, 1H), 3.35 (s, CH2OCH3, 3H), 3.30 (s, CH3, 3H), 3.29-3.25 (m, H-3, 1H), 3.243.20 (m, CH2O, 2H), 2.04-1.21 (m, H-1, H-2, H-5, H-6, 7H). 13C NMR for 5a (100 MHz, CD3OD): δ 80.53 (C-3), 78.46 (CH2O), 69.35 (C-4), 59.00 (CH3), 56.81 (CH3), 32.76 (C-1), 28.57 (C-2 and C-5), 24.39 (C-6). 1H NMR for 5b (400 MHz, CD3OD): δ 3.81-3.76 (m, H-3, 1H), 3.35 (s, CH2OCH3, 3H), 3.30 (s, CH3, 3H), 3.24-3.20 (m, CH2O, 2H), 3.20-3.16 (m, H-4, 1H), 2.041.21 (m, H-1, H-2, H-5, H-6, 7H). 13C NMR for 5b (100 MHz, CD3OD): δ 81.43 (C-4), 78.46 (CH2O), 68.65 (C-3), 59.00 (CH3), 56.92 (CH3), 33.04 (C-2), 32.76 (C-1), 29.11 (C-5), 24.67 (C-6). Anal. Calcd for C9H18O3‚2/11H2O (177.5): C, 60.89; H, 10.43. Found: C, 60.87; H, 10.47. FI-MS: m/z (relative intensity): 174 (M+, 100), 175 (MH+, 24.9). 3,4-Dimethoxy-1-methoxymethyl Cyclohexane (6). Potassium hydroxide powder (2.2 g, 38 mmol) was added to 20 mL of dry
DMSO. After the suspension was stirred for 5 min, 4 (0.77 g, 4.8 mmol) was added, followed by addition of methyl iodide (0.60 mL, 9.6 mmol). The mixture was stirred for 4 h at room temperature, and then 200 mL of water was added to the solution. The solution was extracted with dichloromethane and washed with water (20 mL × 5). The organic phase was dried over potassium carbonate, and the solvent was evaporated. The residue was purified by column chromatography on silica gel with hexane/ethyl acetate (7/3, v/v; Rf ) 0.39) to afford a colorless liquid 6. Yield: 0.65 g (71.8%). 1H NMR (400 MHz, CD OD): δ 3.43-3.39 (m, H-3, 1H), 3.373 3.32 (m, H-4, 1H) including the peaks at 3.34 (s, CH3, 3H) and 3.33 (s, CH3, 3H), 3.29 (s, CH3, 3H), 3.17 (d, J ) 7.0 Hz, CH2O, 2H), 1.91-1.19 (m, H-1, H-2, H-5, H-6, 7H). 13C NMR (100 MHz, CD3OD): δ 79.05 (CH2O), 78.16 (C-4), 78.03 (C-3), 59.00 (CH3), 56.82 (CH3), 56.70 (CH3), 32.68 (C-1), 29.23 (C-2), 24.95 (C-6), 24.31 (C-5). Anal. Calcd for C10H20O3 (188.3): C, 63.80; H, 10.71. Found: C, 63.63; H, 10.71. FI-MS: m/z (relative intensity): 188 (M+, 100), 189 (MH+, 12.4). 1-tert-Butyldimethylsilyloxymethyl-3,4-epoxycyclohexane (3). tert-Butyldimethylchlorosilane (3.90 g, 25.8 mmol) was added to a solution of 1 (3.17 g, 23.4 mmol) and imidazole (3.60 g, 51.6 mmol) in DMF (20 mL) under an argon atmosphere. After the solution was stirred for 6 h at room temperature, the solvent was evaporated to dryness and the residue diluted with ethyl acetate. The solution was washed with water, and the organic phase was dried with MgSO4. After the solvent was removed in vacuo, the crude product was purified by column chromatography on silica gel with hexane/ethyl acetate (9/1, v/v; Rf ) 0.37) and distilled under reduced pressure to afford a colorless liquid 3 containing a mixture of isomers. Yield: 2.75 g (46.9%). Bp: 78 °C (0.25 mmHg). 1H NMR (400 MHz, CD3OD): δ 3.42-3.31 (m, CH2O, 2H), 3.18-3.09 (m, epoxy, 2H), 2.18-0.90 (m, CH and CH2 × 3, 7H), 0.86 (s, CH3 × 3, 9H), 0.00 (s, SiCH3 × 2, 6H). 13C NMR (100 MHz, CD3OD): δ 67.88 (CH2), 67.41 (CH2), 53.00 (CH), 52.73 (CH), 51.91 (CH), 51.47 (CH), 35.41 (CH), 32.41 (CH), 27.98 (CH2), 27.17 (CH2), 25.89 (CH3 × 3), 24.75 (CH2), 23.62 (CH2), 23.13 (CH2), 18.28 (C), -5.44 (CH3 × 2). Anal. Calcd for C13H26O2Si (242.4): C, 64.41; H, 10.81. Found: C, 64.14; H, 10.92. FI-MS: m/z (relative intensity): 242 (M+, 100), 243 (MH+, 42.2). Poly(3,4-epoxycyclohexanemethanol) (poly-3). All procedures were performed under an argon atmosphere (Scheme 2). BF3‚OEt2 (20.5 µL, [M]/[cat.] ) 40) was added to a solution of 2 (1.56 g, 6.41 mmol) in dry-CH2Cl2 (total volume ) 2.50 mL, 2.6 mol‚L-1) at -40 °C using a microsyringe. After 40 h, the polymerization was terminated by adding methanol containing a small portion of an ammonia aqueous solution. The solution was concentrated under reduced pressure, and the original product was fractionated into two parts, i.e., the main part and the oligomer part, using preparative SEC (eluent chloroform). The main product fraction was evaporated and then dried in vacuo to give a white solid. Yield: 0.517 g (33.3%). TBAF (1.0 mol‚L-1 THF solution; 4.2 mL, 4.2 mmol) was added to a solution of the resulting polymer (0.504 g, 2.08 mmol) in THF (20 mL) at room temperature. After 20 h, the solution was evaporated to dryness and the residue purified by reprecipitation with methanol/ethyl acetate. The precipitate was filtered off and dried in vacuo at 40 °C to give a white solid poly-3. Yield: 0.202 g (75.8%). Mw,SEC-MALLS (DMF) (Mw/Mn) ) 16 000 (1.30). dn/dc (DMF) ) 0.068 mL‚g-1. 1H NMR (400 MHz, CD3OD): δ 3.682.88 (m, H-3, H-4, CH2OH, 4H), 1.91-0.90 (m, H-1, H-2, H-5,
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Macromolecules, Vol. 40, No. 26, 2007 Table 1. Cationic Ring-opening Polymerization of 1 and 2 Using BF3‚OEt2a
run 1 2 3 4 5 6 7 8 d
monomer 1 1 1 1 1 1 2 2
solvent PCf CH2Cl2 CH2Cl2 CH2Cl2 none none none none
[M]/[cat.]
temp. (°C)
time (h)
yield (%)b
Mw,SEC (Mw/Mn)c
Mw,SEC-M ALLSd
DBe
40 40 80 80 40 40 20 20
23 23 -5 23 23 100 100 130
48 48 2 2 24 24 98 64
11.8 35.3 44.0 43.6 19.4 25.7 trace trace
1800 (1.36) 3300 (1.49) 3700 (1.72) 3800 (1.81) 3200 (1.82) 4700 (2.11)
