TY - JOUR

T1 - Free-radical copolymerization VII. reinterpretation of velocity-of-copolymerization data

AU - Fukuda, Takeshi

AU - Ma, Yung Dae

AU - Kubo, Keiji

AU - Takada, Akihiko

PY - 1989/12

Y1 - 1989/12

N2 - Velocity-of-copolymerization data available in the literature were reinterpreted on the basis of the current notions that the penultimate-unit effect with respect to absolute values of propagation rate constant (but not with respect to the monomer reactivity ratios) is a general rule, and that the termination step is diffusion-controlled, i.e., normal. By making a few simplifying approximations, a new velocity equation was derived, which was found to describe experimental data generally better than the classical equation based on the terminal propagation model with a single adjustable parameter φ, the cross-termination factor. The single adjustable parameter s included in the new equation, which measures the penultimate-unit effect, was found to have a strong correlation with the monomer reactivity ratios such that the smaller r1r2, the smaller is s, i.e., the more significant is the penulimate-unit effect. This result is in support of the relation r1r2=s1s2 suggested by the phenomenological theory [T. Fukuda et al., Makromol. Chem., Rapid Commun., 8, 495 (1987)].

AB - Velocity-of-copolymerization data available in the literature were reinterpreted on the basis of the current notions that the penultimate-unit effect with respect to absolute values of propagation rate constant (but not with respect to the monomer reactivity ratios) is a general rule, and that the termination step is diffusion-controlled, i.e., normal. By making a few simplifying approximations, a new velocity equation was derived, which was found to describe experimental data generally better than the classical equation based on the terminal propagation model with a single adjustable parameter φ, the cross-termination factor. The single adjustable parameter s included in the new equation, which measures the penultimate-unit effect, was found to have a strong correlation with the monomer reactivity ratios such that the smaller r1r2, the smaller is s, i.e., the more significant is the penulimate-unit effect. This result is in support of the relation r1r2=s1s2 suggested by the phenomenological theory [T. Fukuda et al., Makromol. Chem., Rapid Commun., 8, 495 (1987)].

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U2 - 10.1295/polymj.21.1003

DO - 10.1295/polymj.21.1003

M3 - Article

AN - SCOPUS:0024907289

VL - 21

SP - 1003

EP - 1009

JO - Polymer Journal

JF - Polymer Journal

SN - 0032-3896

IS - 12

ER -