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Home  >  Journal list  >  Polymer Journal  >  Vol.19  No.4 (1987)  >  pp.425-436

Polymer Journal
<<Previous article Vol.19  No.4 (1987)   pp.425 - 436 Next article>>

Two-Dimensional NMR Spectra of Isotactic Poly(methyl methacrylate) Prepared with t-C4H9MgBr and Detailed Examination of Tacticity

Koichi Hatada1), Koichi Ute1), Katsuji Tanaka1), Mamoru Imanari2) and Naoyuki Fujii2)
1) Department of Chemistry, Faculty of Engineering Science, Osaka University
2) JEOL Ltd.


ABSTRACT:  Structures of the chain ends of the low molecular weight and highly isotactic PMMA prepared by t-C4H9MgBr in toluene were investigated extensively using 2D NMR technique. The 1H and 13C NMR signals of α-CH3 and CH2 groups in the first two and the last two monomeric units of the chain were assigned unequivocally, and four types of end-structures, viz. mm and rm at α-end and mm and mr at ω-end were identified. The configurations at the α- and ω-ends were less isotactic than those of in-chain monomeric sequences, and the mr ratios at the α- and ω-ends were 10/1 and 6/4, respectively. Exact tacticity of PMMA was determined on the basis of the assignment, which revealed that isotacticities of the PMMAs prepared with t-C4H9MgBr in toluene at −78°C were independent of molecular weight. Chemical shifts of configuration-sensitive peaks for fractionated dimers and trimers of MMA were found to be very similar to those of the corresponding structures in the polymer ends.


Keyword:
Isotactic Poly(methyl methacrylate)/ Tacticity/ t-Butylmagnesium Bromide/ 1H and 13C NMR/ 2D NMR/ COSY Spectrum/ 2D J-Resolved Spectrum/ Dimer and Trimer of Methyl Methacrylate/ α-End and ω-End/ End Group Analysis

Published online: April 08, 2005
© Copyright, 2005 by The Society of Polymer Science, Japan

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