ABSTRACT:The specific features of free-radical polymerization of methyl methacrylate in the presence of a new initiating system, benzoyl peroxide-N,N-dimethyl-N-(methylferrocenyl)amine, are studied. Mutual influence of ferrocenyl-and amine groups on kinetic parameters of polymerization and on the microstructure of the resulting polymers is found. It is shown that the polymer obtained in the presence of this initiating system has predominantly syndiotactic structure.
Chlorine nuclear quadrupole resonance (NQR) measurements of the effect of the application of uniaxial pressure applied along the (100) and (111) directions in single crystals of K 2 OsCl 6 are reported at 78.0 K. The free induction decay times decrease with pressure due to the additional strains introduced. The corresponding frequency domain spectra indicate that the inhomogeneous broadening of the NQR signals is dominated by point defects, but that the nature, number and/or distribution of these defects is different in the two crystals. The spin-spin relaxation times are dependent on the crystal orientation and are independent of pressure. The measured T 2 -results agree with calculated values. Spin-lattice relaxation data further illustrate the difference between the two crystals. It is described by a single exponential for the (111) crystal, but by a double exponential for the (100) crystal. The latter behaviour indicates the presence of dynamic clusters some 30 K above the temperature of the phase transition. The application of pressure is seen to hinder their formation.
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