Volume 50, Issue 7 pp. 1298-1307
Article

Intramolecular friedel-crafts cyclization and subsequent hydrogenation of styrene-isoprene random copolymers prepared by anionic polymerization for thermally-resistant and optical applications

Atsuhiro Nakahara

Atsuhiro Nakahara

Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan

Kurashiki Research Center, Kuraray Co. Ltd, 2045-1, Sakazu, Kurashiki, Okayama 710-0801, Japan

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Kotaro Satoh

Kotaro Satoh

Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan

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Hiromu Saito

Hiromu Saito

Department of Organic and Polymer Materials Chemistry, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184-8588, Japan

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Masami Kamigaito

Corresponding Author

Masami Kamigaito

Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan

Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, JapanSearch for more papers by this author
First published: 04 January 2012
Citations: 12

Abstract

To synthesize novel thermally and optically high-performing thermoplastics from commodity monomers, random styrene (St)-isoprene (Ip) rubbers (r-SIRs) prepared by anionic copolymerization were subjected to intramolecular Friedel-Crafts cyclization and subsequent hydrogenation via a sequence of simple postpolymerization modifications. The CF3SO3H-catalyzed Friedel-Crafts alkylation of r-SIR afforded cyclized r-SIR (C-r-SIR) via the predominant formation of bicyclic tetrahydronaphthyl units to give thermoplastics with a high glass transition temperature (Tg ∼130 °C), good mechanical properties, and good transparency. Subsequent hydrogenation of the small amount of remaining CC double bonds in the uncyclized Ip units and cyclized Ip-Ip units yielded hydrogenated C-r-SIR (HC-r-SIR) and increased the degradation temperature by about 15 °C (Td5 ≥ 380 °C). These HC-r-SIRs display good flexural moduli and strength, good transparency, and refractive indices similar to those of C-r-SIR. The birefringence of HC-r-SIR was successfully tuned by adjusting the comonomer content to obtain near-zero birefringence high-performance plastics. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

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