Performance evaluation of high‐cis 1,4‐polybutadienes

Abstract

This article reports the results of a study comparing commercially available high-cis polybutadiene rubbers (BRs) proceeding from different production technologies and bearing distinct structural characteristics. The microstructure of these polymers was characterized by Fourier transform infrared spectroscopy; molecular weight and polydispersity values were characterized by size exclusion chromatography (SEC). The degree of branching was characterized by SEC and dynamic mechanical rheological testing (RPA 2000). Glass-transition temperature was characterized by differential scanning calorimetry, and rheological properties were characterized with an oscillating rheometer rubber process analyzer (RPA 2000). Tire tread formulations were prepared with carbon black HAF N-339 as a reinforcement filler, and we compared the mechanical properties and performance of the different elastomer compositions. The compositions were characterized by their rheological properties, tensile resistance, resistance to abrasion, resistance to tearing, permanent deformation, resilience, and fatigue properties. The tested compositions obtained from BRs with distinct structural characteristics showed different performances. Neodymium-salt-based catalysts produced BRs with higher cis-1,4 levels and higher linearities. These polymer compositions also showed higher performances in abrasion resistance, fatigue resistance, and resilience tests.

1,3‐butadiene polymerization using Co/Nd‐based Ziegler/Natta catalyst: Microstructures and properties of butadiene rubber

“…The contents of cis21,4, trans21,4, and vinyl21,2 configurations were calculated following Eqs. (2)(3)(4) …”

“…The BR produced by this system (Ni-BR) has higher linearity and a wider molecular weight distribution with a greater content of cis21,4 configuration (>97%) than that of BR produced by the Co-based system (ca. 96%) [1,4,5].…”

Avaliação das razões molares Cl:Nd e Al:Nd na polimerização de 1,3-butadieno com o sistema catalítico versatato de neodímio/hidreto de di-isobutilalumínio/cloreto de t-butila

“…O cloreto de t-butila, por exemplo, embora pouco citado na literatura como doador de cloro em substituição ao alquil-alumínio clorado é utilizado comercialmente em plantas industriais [1] . Além disso, para o sistema catalítico versatato de neodímio/ hidreto de di-isobutilalumínio/cloreto de t-butila o número de publicações é ainda mais restrito [1,3,5,10,20] . Assim, o objetivo deste trabalho foi estudar os efeitos das razões molares Cl/Nd e Al/Nd sobre a reação de polimerização de 1,4 cis de butadieno com sistemas catalíticos ternários constituídos por versatato de neodímio, cloreto de t-butila e hidreto de di-isobutil-alumínio.…”

“…Uma larga distribuição de massa molar bem como um alto grau de ramificações permite um melhor processamento do polímero, entretanto prejudicam propriedades físicas tais como resistência ao rasgo e à abrasão [3][4][5] . Assim, deve haver um balanceamento dessas características de modo a se ter uma boa processabilidade e boas propriedades físicas.…”

Copolymerization of 1-hexene and 1-dodecene with 1,3-butadiene by a versatate/diisobutylaluminum hydride/t-butyl chloride catalyst system

“…These characteristics contribute to the preservation of nature, because the vehicle will consume less fuel and thus emit less pollutant gases into the atmosphere. Catalyst systems based on neodymium are widely used to produce polybutadiene with high content of 1,4-cis units (98%) [2][3][4][5][6] . However, these catalysts also produce a polymer with high linearity and high molecular weight.…”