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Title: Cationic polymerization of styrene by methanesulfonic acid in dichloromethane

Abstract

Cationic polymerization of styrene has been successfully performed in CH[sub 2]Cl[sub 2] by using CH[sub 3]SO[sub 3]H as an initiator. The initial rate of polymerization (R) was studied and found to obey the rate law R = k[sub obs][Styrene] [CH[sub 3]SO[sub 3]H][sup 2]. The acid-base equilibrium was also studied using various Hammett indicators, (I). Plots of log[IH[sup +]]/[I] vs. log [CH[sub 3]SO[sub 3]H] gave a slope close to 2. The thermodynamic parameters for indicator protonation were determined to be [Delta]H = [minus]13.2 Kcal mol[sup [minus]1]; [Delta]S = [minus]21.2 e.u. The high-order dependence on acid concentration found in both kinetic and equilibrium studies were accounted for by the presence and special effectiveness of hydrogen bonded aggregates. Ion pair dissociation constants, K[sub d], and equivalent conductances at infinite dilution, [Lambda][sub 0], for (n-Bu)[sub 4]N[sup +], CH[sub 3]SO[sub 3][sup [minus]], (n-Bu)[sub 4]N[sup +], ClO[sub 4][sup [minus]], and (n-Bu)[sub 4]N[sup +], CF[sub 3]SO[sub 3][sup [minus]] in CH[sub 2]Cl[sub 2] at 25.0[degrees]C were determined experimentally using the approximate equation of Kraus and Bray. All the salts used in these conductance measurements exhibited a low degree of ionization. A mechanistic scheme is proposed in terms of a chain reaction comprising initiation, propagation, transfer, and termination steps.more » The molecular weights of produced polystyrene characterized by GPC are on the order of (1[minus]7) [times] 10[sup 3], for [CH[sub 3]SO[sub 3]H] = 0.02--0.07M and [Styrene] = 0.07--0.7M. The average degree of polymerization (DP[sub n]) was also studied as a function of styrene concentration. From the Mayo plot, the rate constant ratios, k[sub p]/k[sub ter] [approx] 102 M[sup [minus]1], k[sub p]/k[sub trans] [approx] 29 and k[sub trans]/k[sub ter] [approx] 4 M[sup [minus]1] were calculated.« less

Authors:
Publication Date:
Research Org.:
Washington Univ., Seattle, WA (United States)
OSTI Identifier:
5652600
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; POLYMERIZATION; CHEMICAL REACTION KINETICS; INDICATORS; STYRENE; CATIONS; DISSOCIATION; EQUILIBRIUM; METHYLENE CHLORIDE; POLYSTYRENE; THERMODYNAMIC PROPERTIES; ALKYLATED AROMATICS; AROMATICS; CHARGED PARTICLES; CHEMICAL REACTIONS; HYDROCARBONS; IONS; KINETICS; MATERIALS; ORGANIC CHLORINE COMPOUNDS; ORGANIC COMPOUNDS; ORGANIC HALOGEN COMPOUNDS; ORGANIC POLYMERS; PETROCHEMICALS; PETROLEUM PRODUCTS; PHYSICAL PROPERTIES; PLASTICS; POLYMERS; POLYOLEFINS; POLYVINYLS; REACTION KINETICS; SYNTHETIC MATERIALS; 360601* - Other Materials- Preparation & Manufacture; 400201 - Chemical & Physicochemical Properties

Citation Formats

Miao, E C.Y. Cationic polymerization of styrene by methanesulfonic acid in dichloromethane. United States: N. p., 1992. Web.
Miao, E C.Y. Cationic polymerization of styrene by methanesulfonic acid in dichloromethane. United States.
Miao, E C.Y. Wed . "Cationic polymerization of styrene by methanesulfonic acid in dichloromethane". United States.
@article{osti_5652600,
title = {Cationic polymerization of styrene by methanesulfonic acid in dichloromethane},
author = {Miao, E C.Y.},
abstractNote = {Cationic polymerization of styrene has been successfully performed in CH[sub 2]Cl[sub 2] by using CH[sub 3]SO[sub 3]H as an initiator. The initial rate of polymerization (R) was studied and found to obey the rate law R = k[sub obs][Styrene] [CH[sub 3]SO[sub 3]H][sup 2]. The acid-base equilibrium was also studied using various Hammett indicators, (I). Plots of log[IH[sup +]]/[I] vs. log [CH[sub 3]SO[sub 3]H] gave a slope close to 2. The thermodynamic parameters for indicator protonation were determined to be [Delta]H = [minus]13.2 Kcal mol[sup [minus]1]; [Delta]S = [minus]21.2 e.u. The high-order dependence on acid concentration found in both kinetic and equilibrium studies were accounted for by the presence and special effectiveness of hydrogen bonded aggregates. Ion pair dissociation constants, K[sub d], and equivalent conductances at infinite dilution, [Lambda][sub 0], for (n-Bu)[sub 4]N[sup +], CH[sub 3]SO[sub 3][sup [minus]], (n-Bu)[sub 4]N[sup +], ClO[sub 4][sup [minus]], and (n-Bu)[sub 4]N[sup +], CF[sub 3]SO[sub 3][sup [minus]] in CH[sub 2]Cl[sub 2] at 25.0[degrees]C were determined experimentally using the approximate equation of Kraus and Bray. All the salts used in these conductance measurements exhibited a low degree of ionization. A mechanistic scheme is proposed in terms of a chain reaction comprising initiation, propagation, transfer, and termination steps. The molecular weights of produced polystyrene characterized by GPC are on the order of (1[minus]7) [times] 10[sup 3], for [CH[sub 3]SO[sub 3]H] = 0.02--0.07M and [Styrene] = 0.07--0.7M. The average degree of polymerization (DP[sub n]) was also studied as a function of styrene concentration. From the Mayo plot, the rate constant ratios, k[sub p]/k[sub ter] [approx] 102 M[sup [minus]1], k[sub p]/k[sub trans] [approx] 29 and k[sub trans]/k[sub ter] [approx] 4 M[sup [minus]1] were calculated.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {1}
}

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