Polymerisation of N-vinylcarbazole. Part 1.—End-group studies on polymers prepared using azobisisobutyronitrile and benzoyl peroxide

ABSTRACT:Pulsed-laser polymerization in conjunction with molecular weight distribution measurement was adopted for determining the propagation rate coefficient kP in the free radical solution polymerization of N-vinylcarbazole (VCZ). A photoinitiator which absorbs up to ca. 410nm was selected to exclude the excitation ofVCZ. We measured the effects of light intensity, pulse frequency and the concentration of VCZ on the rate coefficients. The value kp=4.16 x 10 3 Lmol-1 s-1 was obtained in benzene at 30oC. The values of kP were well fitted by the Arrhenius equation in the range of 3o--70"C. The values evaluated by using the non-linear least-squares fitting for determination of Arrhenius parameters were A= 2.20 x 10 8 L mol-1 s-1 and EA =27.4kJ mol-1 . We obtained the 95% joint confidence interval for the Arrhenius parameters.KEY WORDS N-Vinylcarbazole I Radical Polymerization I Propagation Rate Coefficient I Pulsed-Laser Polymerization IThe radical and cationic polymerization of N-vinylcarbazole (VCZ) has been extensively studied. 1 · 2 In the polymerization kinetics, it is important to determine the propagation rate constant kP. North et al. 3 measured the propagation rate constant for radical polymerization of VCZ by using the rotating sector-dilatometry method and reported the value of kP = 13 L mol-1 s-1 in tetrahydrofuran (THF) at 30°C, which is listed in the "Polymer Handbook". 4 We have reported a much higher value of kP = 930 L mol-1 s -I in benzene at 30°C by the same method. 5 Recently, Olaj and coworkers 6 developed the pulsed-laser polymerization (PLP) technique by which the propagation rate constant of radical polymerization can be evaluated accurately. In this technique the propagation rate constants can be estimated from the molecular weight distribution of the obtained polymer. The original concept was outlined by Aleksandrov. 7 Many workers have determined the propagation rate constants for various different monomer systems, such as styrene, 8 -10 acrylate, 11 -13 methacrylate 14 -19 and vinyl acetate. 20 These studies were carried out mostly using bulk polymerization and a few using solution polymerization. 21 -23 In this study, the propagation rate constant of VCZ was measured in solution with an appropriate photoinitiator by the PLP technique. The absorption of VCZ has a long wavelength tail in the UV region, i.e., the absorption maximum is at 340 nm and the tail extends to 390 nm at a high monomer concentration, so we adopted the photoinitiator whose absorption band is in a longer wavelength than the absorption of VCZ. EXPERIMENTAL VCZ (Nakarai tesque) was purified by recrystallization three times from methanol and hexane. Then it was dried in vacuo for two days at room temperature. The solvent was purified by the usual way. In this study, we used 2-benzyl-2-dimethylamino-1-( 4-morpholinophenyl)-butanone-1 (Irgacure 369, Ciba Geigy) as a photoinitiator which has an absorption tail up to ca. 878410 nm. Figure 1 shows the molecular structure of the initiator and monomer. The solution in the sam...

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“…34 The present study showed a way to measure the rate constants of radical polymerization in solution.…”

Section: Methodsmentioning

confidence: 99%

Determination of Propagation Rate Coefficient of Free-Radical Polymerization of N-Vinylcarbazole by Pulsed-Laser Polymerization

Ohoka

Misumi

Yamamoto

1999

Polym J

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“…However, frequent chain transfer reactions to monomer makes it unfavorable to obtain HMW PVCZ of superior molecular structure. 16,18,19 This is more problematic for conventional solution polymerization usually conducted at temperatures above 40°C.…”

Section: Introductionmentioning

confidence: 99%

“…Free radical polymerizations of VCZ using azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO) as initiators have been performed to prepare PVCZ of a molecular weight of below 100,000. 16,18,19 In free radical bulk polymerization of VCZ, an increased polymerization rate arising from greater temperature rises at higher polymerization temperature lowered the molecular weight of PVCZ. High molecular weight (HMW) PVCZ is, therefore, hardly obtained by this method.…”

Section: Introductionmentioning

confidence: 99%

Low‐temperature photoinitiation solution polymerization behavior of N‐vinylcarbazole in tetrahydrofuran

Lyoo

Ghim

Kim³

et al. 2002

J of Applied Polymer Sci

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N-Vinylcarbazole (VCZ) was solution-polymerized in tetrahydrofuran (THF) at Ϫ20, 0, and 20°C using the photoinitiation method; the effects of the amount of solvent, polymerization temperature, and photoinitiator concentration were investigated. On the whole, the experimental results corresponded to predicted ones. Low polymerization temperature using photoinitiation proved to be successful in obtaining poly(N-vinylcarbazole) (PVCZ) of a high molecular weight with a smaller temperature rise during polymerization; nevertheless of free radical polymerization by 2,2Ј-azobis(2,4-dimethylvaleronitrile) (ADMVN). The photo-solution polymerization rate of VCZ in THF was proportional to the 0.47 power of ADMVN concentration. The molecular weight was higher and the molecular weight distribution was narrower with PVCZ polymerized at lower temperatures. For PVCZ prepared in THF at Ϫ20°C using a photoinitiator concentration of 0.00005 mol/mol of VCZ, a weight-average molecular weight of 510,000 was obtained, with a polydispersity index of 1.73, and a degree of lightness converged to about 99%.

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“…Synthesis of PA by classical radical polymerization has been widely studied [9][10][11]. Using the azoic initiator azoisobutyronitrile (AIBN) led to conventional radical polymerization while using benzoic peroxide (BPO) led to cationic and radical mechanisms [12].…”

Section: Introductionmentioning

confidence: 99%

Radical copolymerization of N-vinylcarbazole and p-bromostyrene: determination of monomer reactivity ratios by SEC-multidetection

Lateulade¹,

Grassl²,

Dagron‐Lartigau³

et al. 2006

Polymer

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Polymerisation of N-vinylcarbazole. Part 1.—End-group studies on polymers prepared using azobisisobutyronitrile and benzoyl peroxide

Cited by 25 publications

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Determination of Propagation Rate Coefficient of Free-Radical Polymerization of N-Vinylcarbazole by Pulsed-Laser Polymerization

Determination of Propagation Rate Coefficient of Free-Radical Polymerization of N-Vinylcarbazole by Pulsed-Laser Polymerization

Low‐temperature photoinitiation solution polymerization behavior of N‐vinylcarbazole in tetrahydrofuran

Radical copolymerization of N-vinylcarbazole and p-bromostyrene: determination of monomer reactivity ratios by SEC-multidetection

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