THE MECHANISM OF INTERACTION OF SULPHUR AND p-PHENYLENEDIAMINE

Abstract

Several studies which have been undertaken on reaction of sulphur and p-pheaylenediamine give controversial proposals of mechanisms. Many authors postulate an attack of sulphur diradicals directed onto amino group.     

Linear baryons and SU(3) breaking

The recently proposed mechanism of dynamical SU(3) symmetry breaking in linear baryons is applied to the α-γ sector after taking into account two types of α and γ trajectories. The observed splitting pattern of leading strange baryon trajectories is qualitatively explained. The implications of the scheme for ground state baryons are discussed.     

Screening of metal catalysts influence on the synthesis,structure, properties,and biodegradation of PLA‐PBA triblock copolymers obtained in melt

The synthesis of ABA type triblock copolymers comprising poly(1,4‐butylene adipate) macroinitiator and polylactide segments is described in this article. Acetylacetonates of various low‐toxic metals: Li, Mg, Ca, Zn, Fe, and Zr are used as catalysts. The course of polymerization, microstructure, thermal properties, and biodegradation of the copolymers obtained are analyzed based on the electronegativity of the metal used. The macroinitiator is completely incorporated into the major products, however, linear and cyclic lactide homopolymers and copolymers are present because of moisture presence and transesterification processes. The efficiency of side reactions depends on the catalyst used. The highest molar mass of copolymer is obtained with a Zr‐based catalyst. The efficacy of polylactide racemization is higher for catalysts comprising the metal of lower electronegativity. Under thermal degradation conditions the polylactide segment degrades before the macroinitiator one. The copolymers studied undergo faster biodegradation than polylactide and they can decompose in compost within 16 weeks. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1444–1456