Synthesis and Characterization of - 多面體聚矽氧烷為建構單元的嵌段式共聚物奈米複合材料及金屬晶粒複合奈米粒子

Poly(ε-caprolactone-b-4-vinyl pyridine): Initiation, Polymerization, Solution Morphology, and Gold Metalation

Abstract

We have synthesized a difunctional initiator—the hydroxyl-4-oxo--alkoxyamine HOA—by first mixing benzoyl peroxide (BPO) and 4-hydroxyl 2,2,6,6-tetramethylpiperdinooxy (4-OH-TEMPO) in styrene at temperatures below 25 °C to give the 4-oxo--alkoxyamine (OA) and then hydrolyzing the benzoate ester on OA with NaOH. This low-temperature preparation of OA reveals that benzyloxyl radicals can be generated from the BPO through redox reaction with 4-OH-TEMPO as well as through thermal decomposition. The

-oxoammonium cation (i.e., the oxidative state of 4-OH-TEMPO), which formed as a side product, mediated the alcohol oxidation to give OA. We prepared three PCL-b-P4VP diblock copolymers (BC1–3) from HOA through two-step polymerizations: (i) diethyl aluminum alkoxide-induced ring-opening polymerization of ε-caprolactone at 25 °C followed by (ii) nitroxide-mediated radical polymerization of 4-vinylpyridine at 125 °C. With the combination of biodegradable hydrophobic PCL blocks and polymeric blocks of P4VP ligands, we used the immiscible PCL-b-P4VP copolymers to transport AuCl4–

anions from aqueous phases to organic phases and to stabilize Au nanoparticles in the PCL-b-P4VP micelles Au-BC1–3 after reduction with NaBH4.

2-1 Introduction

Diblock copolymers comprising two dissimilar blocks can form two separate and thermodynamically stable microstructures in the bulk state. The hydrophilic side groups of amphiphilic diblock copolymers are highly permeable to water^1–6 or can be selectively removed to create nanopores for water passage.^7,8 When placed in a solvent that solvates only one of the components well, diblock copolymers self-assemble into core/shell micellar microstructures in which the insoluble block comprises the core, thereby avoiding contact with the solvent.⁹ In their pioneering research, Eisenberg and coworkers observed that micelles formed from linear diblock copolymers in several morphologies, including spheres, rods, vesicles, and large compound micelles.^10–12 Depending on the molecular masses of the two blocks, the sizes of micelles can range from 10 to 1000 nm, providing a large contact area for two-phase extraction of metal ions: one block to capture metal ions from water in the insoluble cores and the other to stabilize the micelles in organic solvent.

Metal-binding polymers are usually amphiphilic because of the need for highly polar interactions (e.g., ionic bonds) between the metal ions and the polymer. Therefore, hydrophobic nonmetallic PCL block is necessary to form the shells of diblock-copolymer micelles in organic solvent while P4VP block captured metal ions from aqueous phase or protecting metal nanoparticles after reduction for two-phase extraction of metal ions. Biodegradable and biocompatible polymers are better choices for use as shell components, i.e., to minimize the use of chemicals and the impact on the environment.¹ For example, poly(ε-caprolactone-block-4-vinylpyridine) (PCL-b-P4VP) is such a diblock copolymer that forms core/shell micelle structures in toluene.¹³

Gold nanoparticles (Au NPs)¹⁴ have recently found many applications in industrial chemistry, such as in low-temperature CO oxidation,^15,16 hydrocarbon

hydrogenation,^17–19 low-temperature hydrocarbon oxidation,^20,21 and NO reduction.²² Most Au NPs are prepared through the chemical reduction of tetrachloroaurate (AuCl₄^–) using reducing agents such as sodium borohydride,²³ hydrazine,²⁴ or lithium borohydride.²⁵ The protonated pyridyl nitrogen atoms of P4VP blocks form ionic bonds with AuCl₄^– ions and they also coordinate to the Au NPs formed after reduction of these ions.^24–27 Thus, PCL-b-P4VP copolymer micelles can be prepared to capture AuCl₄^– ions from water and to recycle Au NPs into organic solvents.

PCL-b-P4VP copolymers can be synthesized through ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) followed by free radical polymerization (FRP) of 4-vinylpyridine (4-VP). After ligand exchange of the hydroxyl groups with either stannous(II) octoate [Sn(Oct)₂] or aluminum tris(isopropoxide) [Al(iOPr)3], the stannous alkoxide group (SnOR) can catalyze the bulk ROP of ε-CL at 110 °C or the aluminum alkoxide group (Al-OR) can initiate ROP of ε-CL at 25 °C in toluene or tetrahydrofuran.^28,29 Living free radical polymerizations (LFRPs) exhibiting low degrees of radical termination are necessary for polymerization of the second P4VP block from the PCL-macroinitiator.³⁰ In such LFRPs as atom transfer radical polymerization (ATRP), nitroxide-mediated radical polymerization (NMRP), and reversible addition fragmentation (RAFT), the propagating radicals P^• react reversibly with inert persistent species T [e.g., a Cu(I) complex for ATRP, a stable nitroxide free radical (e.g., TEMPO or 4-OH-TEMPO in this study) for NMRP, or a dithioate for RAFT] to form reversible dormant products (P-T), significantly increasing the selectivity (rp/rt = ca. 1/[P^•]) of propagation (rp = ca.

[P^•]) to termination (r_t = ca. [P^•]²), where r_p, r_t, and [P^•] are the rates of propagation and termination and the concentration of the propagation radical, respectively.^31–33 Because the strong metal ligands of the P4VP block react with copper cations to form metal complexes during ATRP, purification of the resulting polymers can be very

time-consuming and repetitious. Using the RAFT technique, the dithioate reagents can bond with the metal ions. Thus, it is not easy to incorporate dithioate groups onto the chain end of PCL for preparation of PCL-b-P4VP block copolymers. The use of styrenic monomers, a unimolecular initiator, and bulk polymerization are the three major limitations of the TEMPO-mediated NMRP because of the high dissociation energy of the C–O bonds on the -alkoxyamine groups, the high reactivity of TEMPO, and the ready transfer of the free radicals to the solvent. In the absence of a metal catalyst, NMRP remains the preferable route toward PCL-b-P4VP copolymers.³⁴ Moreover, Hawker et al. succeeded in the preparation of poly(ε-caprolactone-block-styrene) through the ROP of ε-CL and the NMRP of styrene when using hydroxyl-functionalized -alkoxyamines (the same structure as HA in this study) as difunctional initiators.³⁵

During the propagation step of TEMPO-mediated NMRPs using a starting material of benzoyl peroxides (BPOs) at 120 °C, a vinyl monomer is inserted into the C–O bond of the -alkoxyamine end-group (Scheme 2-1b), which arises as the product of the radical addition between a carbon-centered radical and TEMPO (Scheme 2-1a). Such -alkoxyamine products are stable at temperatures below 50 °C and, thus, they can be isolated for use as unimolecular initiators for one-step polymerizations at 120 °C.³⁶ In contrast, the in situ preparation of -alkoxyamine intermediates—by mixing a radical source (e.g., BPO or AIBN) and a stable nitroxide free radical (e.g., TEMPO or 4-OH TEMPO)—allows them to be used as bimolecular initiators for two-step polymerizations (e.g., one performed at 80 °C for 2 h and the other at 120 °C for 24 h; Scheme 2-1). In 1993, it was determined that the optimal TEMPO addition for living polystyrene polymerization was 1.3 equivalents relative to BPO (rather than the two-fold ratio expected theoretically), implying that side reactions occurred for the bimolecular initiator.^37,38 The decomposition temperature

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(T_d, i.e., the temperature at which half of the concentration is consumed within 1 h) of the BPO is 92 °C in toluene. Thus, the reaction temperature for the preparation of

-alkoxyamines using BPO and TEMPO in styrene has been established to be 80 °C.

A 42% yield of -alkoxyamine products was obtained after column chromatographic purification at this reaction temperature.³⁶ Gravert and Janda found, however, that this product was formed in 34% yield at 50 °C.³⁹ Moad et al.^40,41 and Veregin et al.⁴² studied the mechanism of the reaction between BPO and TEMPO in styrene at 60 °C.

In addition to the thermolysis of BPO, they found that TEMPO can react with BPO to give the benzoxyloxyl radical, benzoate anion, and -oxoammonium cation through one-electron transfer. Unfortunately, this redox reaction has been studied only rarely, even though NMRP has been applied widely to polymer synthesis since 1993.³⁷ Many reports mention that high-temperature decomposition of BPO results in radical-induced side reactions and, thus, low yields (<50%) of -alkoxyamine products. We suspected that TEMPO-induced BPO decomposition could be a major reason for this behavior because an equimolar amount of TEMPO is required to prepare the benzoyoxyl radicals in this reaction pathway. For this purpose, it was necessary to clarify the mechanism of the reaction occurring between BPO and TEMPO in the styrene medium prior to NMRP. Braslau et al. demonstrated many alternative methods for generating carbon-centered radicals at temperatures below 50

°C for preparing high-yield -alkoxyamine products as unimolecular initiators for NMRP; these methods included PbO₂-mediated oxidation of benzyl hydrazine, Cu^II-mediated oxidation of lithium enolates, and hydrogen or halide abstraction with non-carbon-centered radicals formed through photolysis or low-temperature thermolysis.⁴³ Nevertheless, most polymer chemists still select the BPO-TEMPO initiation system to prepare -alkoxyamine unimolecular initiators because of its low-cost raw materials and simplicity. In addition, the benzoic ester products of

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-alkoxyamines can be used in many wide-ranging applications after alkaline hydrolysis. Use of the commercially available 4-hydroxyl-TEMPO is another option because the additional hydroxyl unit on the nitroxyl moiety is another group that can be converted into a variety of functionalities through chemical modification. Yin et al.

attempted to prepare 4-OH-TEMPO-based -alkoxyamines, but found that major products of the 4-hydroxyl--alkoxyamines were oxidized to 4-oxo--alkoxyamines, resulting in 8.6 and 18.5% yields for the 4-hydroxyl- and 4-oxo--alkoxyamines, respectively.⁴⁴ Thus, Hawker et al. protected the hydroxyl unit of 4-hydroxyl-TEMPO in the form of its benzoate ester to prepare diol -alkoxyamines for the radical

Scheme 2-1. Synthetic route toward NMRP through BPO-TEMPO bimolecular initiation: (a) -alkoxyamine initiator formation; (b) styrene monomer insertion.

In this study, we synthesized the hydroxyl-functionalized -alkoxyamine HOA for use in PCL-b-P4VP diblock copolymerizations employing sequential ROP and NMRP procedures in one batch. When preparing the -alkoxyamines A and OA,

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heating was unnecessary, but the reaction rates were suppressed upon immersing the flask in an ice bath. The color of the solution changed from reddish brown to pale green initially for the reactions proceeding at temperatures below 25 °C. The comprehensive reaction mechanism was deduced after structural identification of the

-alkoxyamine products and their side products. With the stable nitroxide free radical of 4-OH-TEMPO, the product of HOA was used to initiate the ROP of ε-CL in toluene at 25 °C after the reaction with triethylaluminum (AlEt₃). The PCL-b-P4VP copolymers were obtained through bulk NMRP of 4-VP from PCL macroinitiators at 125 °C. Using ¹H NMR spectroscopic and GPC analyses, the living behavior of the ROP was confirmed by the linear relationship between the monomer conversion and the polymer molecular mass because all of the monomers were inserted from the aluminum alkoxide (Al-OR) bonds. Two HOA-to-AlEt3 molar ratios (r = 1:1.2 or 1:0.6) were investigated for a kinetic study for the ROP of ε-CL in toluene (v = 30 or 60 mL). When r and v were 1.5 and 30 mL, respectively, the 99.5% conversion of the ε-CL monomers was achieved and then the solution batch was allowed to proceed via the NMRP of 4-VP at 125 °C after vacuum distillation of toluene. The similar trends in the GPC traces obtained using RI and UV dual detectors provided evidence for the NMRP of 4VP from the PCL-macroinitiator, i.e., because only the P4VP blocks absorb UV light. DSC thermograms revealed two glass transition temperatures—i.e., distinct thermal chain motions in the separation microdomains of the PCL and P4VP blocks—confirming that immiscible PCL-b-P4VP diblock copolymers had formed.

After staining the P4VP cores with RuO4 vapor, TEM images revealed micellar

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(NH⁺···AuCl4–

). Upon reduction with aqueous NaBH₄ solution, Au NPs were formed in the P4VP block core. As a result, the organic phase became yellow after two-phase extraction, but turned red after reduction. After the addition of excess toluene, we used UV–Vis spectroscopy, DLS, and TEM to analyze the Au NPs formed through PCL-b-P4VP copolymer-mediated reduction in the solvent selective for the PCL block.

2-2 Experimental Section 2-2.1 Materials.

ε-Caprolactone (ε-CL, 99.5%, ACROS), 4-vinylpyridine (4-VP, 99.5%, ACROS), and toluene (HPLC grade, TEDIA) were dried over calcium hydride (CaH₂, 95%, ACROS) for 24 h and then distilled under reduced pressure. The following chemicals and solvents were used as received: benzoyl peroxide (BPO, >97%, Fluka), styrene (St, 99%, ACROS), 2,2,6,6-tetramethylpiperidinooxy (TEMPO, 98%, ACROS), 4-hydroxy-2,2,6,6-tetramethylpiperidinooxy (4-OH-TEMPO, 98%, ACROS), triethylaluminum (AlEt3, 0.9 M in hexane, Fluka), glacial acetic acid (HPLC grade, TEDIA), cyclopentanol (a, 99%, Alfa Aesar), hydrogen tetrachloroaurate(III) trihydrate (HAuCl4·3H2O, 99.9%, ACROS), sodium borohydride (NaBH₄, 99.5%, ACROS), cyclohexanol (b, 99%, Alfa Aesar), cycloheptanol (c, 95%, Alfa Aesar), 1-pentanol (d, 98%, ACROS), 2-octanol (e, 97%, ACROS), tetrahydrofuran (THF, HPLC grade, TEDIA), methanol (MeOH, HPLC grade, TEDIA), and diethyl ether (Et2O, HPLC grade, TEDIA). Reactions were performed in glassware under a static atmosphere of argon.

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2-2.2 Measurement.

¹H and ¹³C NMR spectra were recorded using a Varian Unityinova 500 NMR spectrometer. Elemental analyses were performed using a Heraeus CHN-O Rapid apparatus (Heraeus VarioEL). MS/MS measurements were performed using an ESI quadrupole time-of-flight instrument (Q-TOF; Micromass) operated in positive ion mode. GC-MS analyses were performed using a Trio 2000 quadrupole mass spectrometer (Micromass, Manchester, UK) equipped with a Fisons Instruments 8060 gas chromatograph and a fused silica capillary column (length: 30 m; inner diameter:

0.5 mm; film thickness: 0.25 µm) from Supelco. EI-MS analyses were performed through continuous quadrupole scanning at an ionization energy of 70 eV. UV–Vis spectra were measured using a UV-1601 spectrophotometer (Shimadzu, Japan).

Melting points were measured on a Fargo MP-2D apparatus. The weight-average (M_w), number-average (M_n), and maximum (M_v) molecular weights and the polydispersity index (Mw/Mn) were determined through gel permeation chromatography (GPC) using a Waters 510 HPLC, equipped with a 410 differential refractometer, a refractive index (RI) detector, and three Ultrastyragel columns (100, 500, and 103) connected in series in order of increasing pore size, with DMF as eluent at a flow rate of 0.6 mL/min. DLS measurements were performed on a Brookhaven photon correlation spectrometer with BI9000 AT digital correlation. The instrument was equipped with a compass 315M-150 laser (Coherent Technologies), which was operated at a wavelength of 532 nm. Dust-free vials were used for sample preparation at a concentration of 1 mg/mL in a mixture of 10% DCM/90% toluene (v/v);

measurements were made at 25 °C at an angle of 90°. The CONTIN algorithm was used to analyze the data. A DuPont DSC-9000 calorimeter, operated at a scan rate of 20 °C/min over the range from –100 to +180 °C, was used to record the DSC thermograms of samples (ca. 5–10 mg) sealed in aluminum pans. The temperature and

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energy were calibrated with indium. The glass transition temperature was obtained as the midpoint of the specific heat increment. A TA Instruments thermogravimetric analyzer, operated at a scan rate of 20 °C over temperatures ranging from 30 to 800

°C under a nitrogen purge of 40 mL/min, was used to record TGA thermograms of samples on a platinum holder. A Hitachi H-7500 transmission electron microscope (100 kV) was used to record TEM images of the diblock copolymer micelles after staining with RuO₄ vapor. A drop of dilute solution (1 mg/mL) was placed onto a carbon-coated copper grid. After 3 min, the excess solution was blotted away using a strip of filter paper. The samples were air-dried at room temperature and then stained with RuO4 vapor.

2-2.3 UV–Vis Calibration of TEMPO Concentration.

The concentration of TEMPO in a reaction mixture can be determined using the Beer–Lambert law (A = εbc) by monitoring the characteristic UV–Vis signal of TEMPO at 469.5 nm (Figure 2-1). In this equation, A is the absorbance at 469.5 nm in the UV–Vis spectrum, ε (L/mol/cm) is the molar absorptivity of TEMPO in THF, c (mol/L) is the concentration of TEMPO, and b (cm) is the path length of the sample holder. The constant εb was calculated to be 10.59 L/mol from the slope of the linear curve fitting the absorbance to the concentration (Figure 2-2). Therefore, the concentration of TEMPO at a given time interval can be deduced from the expression A/(εb). To ensure that all data were located on the calibration curve, the reaction mixtures were diluted with THF prior to analysis. The TEMPO calibration curve correlating the absorbance at 469.5 nm to the concentration, y = 0.00596 + 0.01059x (R² = 0.9995), was determined from UV–Vis spectroscopic analysis of the standard solutions of TEMPO in THF.

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350 400 450 500 550 600 650 700 750 800 0.0

Figure 2-1. UV–Vis spectra of TEMPO in THF at various concentrations.

0 10 20 30 40 50 60 70

Figure 2-2. TEMPO calibration curve, correlating the absorbance at 469.5 nm to the concentration in THF.

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2-2.4 Syntheses of -Alkoxyamines.

A solution of BPO (15.0 g, 61.9 mmol) and TEMPO (5.0 g, 32 mmol) or 4-hydroxy TEMPO (5.5 g, 32 mmol) in styrene (50 mL) was cooled to 5 °C in an ice bath and then naturally warmed to room temperature after a removal of the bath. The reddish-brown solution gradually faded, turning into a pale green solution over several hours. The excess styrene was removed through vacuum distillation and the residual solid was partitioned between diethyl ether and 1 N aqueous NaOH. The product in the organic phase was dried (anhydrous MgSO4) and the solvent was evaporated to give a light-yellow powder. White crystals of -alkoxyamine products—the -alkoxyamine A (5.2 g, 43%) and 4-oxo--alkoxyamine OA (4.3 g, 37%)—were obtained after recrystallization from MeOH. Melting points: A, 74.5 °C;

OA, 111.0 °C. Mass spectra (ESI, m/z): A, 382.1 [MH⁺]; OA, 396.2 [MH⁺]. Elem.

Anal. for A (C₂₄H₃₁NO₃): Calcd: C, 75.56; H, 8.19; N, 3.67; Found: C, 75.66; H, 8.23;

N, 3.46; for OA (C24H29NO4): Calcd: C, 72.89; H, 7.39; N, 3.54; Found: C, 72.84; H, 7.45; N, 3.31. ¹H and ¹³C NMR spectra of A and OA are presented in Figure 2-3.

FTIR spectra of A and OA are presented in Figure 2-4.

Figure 2-3. (a) ¹H and (b) ¹³C NMR spectra of the -alkoxyamine A and the 4-oxo--alkoxyamine OA formed from the reaction between BPO and TEMPO or 4-OH-TEMPO in styrene at temperatures below 25 °C.

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Figure 2-4. FTIR spectra of (a) the -alkoxyamine A and (b) the 4-oxo--alkoxyamine OA.

2-2.5 Synthesis of Hydroxyl--alkoxyamines.

10 N Aqueous NaOH (10 mL) was added dropwise to a solution of the

-alkoxyamine adduct A (5.0 g, 13.1 mmol) or OA (5.0 g, 12.6 mmol) in a mixture of THF (10 mL) and MeOH (30 mL). After several hours, the solvent was removed through rotary evaporation and the product was washed with excess diethyl ether.

After rotary evaporation, HA (3.3 g, 90 %) was obtained as a light-yellow liquid or HOA (3.2 g, 87 %) was obtained as a white solid (m.p. 69.2 °C). Mass spectra (ESI, m/z): HA, 278 [MH⁺]; HOA, 292 [MH⁺]; Elem. Anal. for HA (C₁₇H₂₇NO₂): Calcd: C, 73.61; H, 9.81; N, 5.05; Found: C, 73.79; H, 9.57; N, 4.95; for HOA (C17H25NO3):

Calcd: C, 70.07; H, 8.65; N, 4.81, Found: C, 69.96; H, 8.76; N, 5.43. The ¹H and ¹³C NMR spectra of HA and HOA are presented in Figure 2-5; their FTIR spectra appear in Figure 2-6, respectively.

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Figure 2-5. (a) ¹H and (b) ¹³C NMR spectra of HA and HOA.

Figure 2-6. FTIR spectra of (a) hydroxyl the -alkoxyamine HA and (b) hydroxyl the 4-oxo--alkoxyamine HOA.

2-2.6 Synthesis of -Alkoxyamine-Functionalized Poly(ε-caprolactone).

A solution of AlEt3 (ca. 0.9 mol/L in hexane, 0.42 mL) was added to a solution of hydroxyl-4-oxo--alkoxyamines (HOA, 27.8 mg, 0.25 mmol) in dry toluene (5 mL) under an argon atmosphere. The mixture was stirred at room temperature for 30 min, and then the resultant ethane was removed under reduced pressure. After adding dry toluene (25 mL), the flask was cooled in an ice bath and then ε-CL (5 mL) was quickly injected into the reaction mixture. The polymerization was performed at 25

°C for a given time and then stopped through the addition of glacial acetic acid (0.2 mL). After evaporation of the toluene through vacuum distillation, the PCL macroinitiator was used directly for the polymerization of 4-VP.

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2-2.7 Synthesis of Poly(ε-caprolactone)-block-poly(4-vinylpyridine) Copolymers.

The dried PCL macroinitiator was charged with one, two, or four equivalents of the 4-VP monomer, based on the content of ε-CL. The vessel was immersed in an oil bath maintained at a temperature of 125 °C. When the stirrer bar stopped stirring in the highly viscous solution, the polymerization was quenched through immersion of the flask in an ice bath. The resultant diblock copolymers BC1–3 were purified twice through dissolution in chloroform and precipitation from hexane.

2-2.8 Preparation of Micelle Solutions.

The diblock copolymer was dissolved DCM, a good solvent for both blocks, at a concentration of 10 mg/mL. Next, a poor solvent for one of the blocks was added to the polymer solution very slowly (up to 90%, v/v) to obtain a desired concentration of 1 mg/mL. Stirring of the solution was continued for 1 hrs (Figure 2-12 and Figure 2-14a) and 24 hrs (Figure 2-14b) prior to characterization.

2-2.9 Synthesis of PCL-b-P4VP Copolymer-Mediated Au <Ps.

Equimolar amounts of the pyridine units of the PCL-b-P4VP copolymers BC1–3 in DCM (10 mL) were added to an AuCl4–

solution (30 mM, 10 mL) under stirring with a magnetic bar stirring. After 1 h, aqueous NaBH₄ solution (300 mM, 10 mL) was added and then the mixture was stirred for another 1 h. The PCL-b-P4VP copolymer-protected Au NPs Au-BC1–3 were stabilized after adding toluene and separating the organic phase.

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2-3 Results and Discussion 2-3.1 -Alkoxyamines.

In comparison with bimolecular initiation, unimolecular initiation of NMRP provides improved control over the molecular mass distribution with narrow polydispersity (M_w/M_n < 1.5). Therefore, we prepared -alkoxyamine unimolecular initiators for the synthesis of PCL-b-P4VP diblock copolymers using benzoyl peroxide (BPO) and 2,2,6,6-tetramethylpiperdinooxy (TEMPO) in the styrene medium. We observed, however, abnormal release of heat, resulting in the temperature increasing up to 50 °C, after mixing BPO with TEMPO in the styrene medium at 25 °C. Thus, this exothermic reaction should be suppressed by cooling, rather than heating. Because of the low solubility of BPO in styrene at temperatures below 20 °C, we controlled this reaction by dissolving BPO slowly during natural warming at temperatures between 5 and 25 °C. Remarkably, the color of the solution turned from reddish brown to pale green (Figure 2-7b), indicating consumption of TEMPO (note that reddish brown is the intrinsic color of stable nitroxide free

在文檔中多面體聚矽氧烷為建構單元的嵌段式共聚物奈米複合材料及金屬晶粒複合奈米粒子 (頁 129-168)