Mixture of two catalysts in one reactor for ethylene/α-olefin copolymerization in the solution process can result in the combination of microstructures related to both catalysts in the polymer framework. Thus, novel polymer configuration is synthesized, which is characterized by containing sequences of monomers produced with each catalyst in the same polymer chain. Adding a reversible transfer agent (CSA) to the binary system enables the production of new block copolymers with enhanced properties. Late transition metal catalysts, such as α-diimine nickel catalyst when activated with methylaluminoxane (MAO) show high activity towards olefin polymerization and produces highly branched homopolymers. On the other hand, C 2 symmetry metallocene catalysts produce linear polyethylenes. This paper describes the synthesis of ethylene homopolymer with amorphous and crystalline blocks using a binary mixture containing a nickel catalyst with α-diimine ligand, which produces ф highly branched polyethylene (soft PE) and a metallocene (rac-ethylene bis(H 4-indenyl)ZrCl 2) that converts ethylene into polyethylene with high activities and melting temperatures (hard PE). The influence of polymerization temperature and CSA concentration were investigated. The polymeric materials were characterized by density, thermal properties, X-ray diffractometry and dynamic-mechanical properties.

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A NOTE ON THE TRANSPOSITION OF CHEMICAL TERMS ONTO THE PORTUGUESE LANGUAGE. This note has the purpose of calling the attention of the chemist to some aspects of the process of translating chemical terms onto the Portuguese language. A quick inspection on the chemistry literature in Portuguese shows a certain number of inadequate or dubious translations of terms originally coined in other languages. Firstly, the possible origins of these inadequacies are briefly discussed. Then one proceeds to a cursory explanation of some fundamental concepts such as signs, words, meaning, real referents, scientific concept, and scientific term. These concepts are traced back to the origin of Western Civilization, being first systematized in the work of Aristotle, forming the backbone of all Western languages. A short discussion on the features of a well-done translation is presented. Finally, a set of ill-translated or dubiously translated or dubiously named chemical terms are used to illustrate the presented concepts, divided among the general type of inadequacy. In some cases, with justification, grammatically correct or more adequate terms are suggested to replace the offending translated chemical terms in portuguese.