Synthesis of Highcis-1,4-BR with Neodymium for the Manufacture of Tires

Maria Leonor Méndez-Hernández,Beatriz Adriana Salazar-Cruz,Sergio Corona Galvan,Ricardo García-Alamilla,José Luis Rivera-Armenta,Ulises Páramo-García

doi:10.1155/2016/7239540

Maria Leonor Méndez-Hernández, Beatriz Adriana Salazar-Cruz + Show 4 more

Open Access

https://doi.org/10.1155/2016/7239540

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Abstract

The salt of neodymium has been widely used in industrial polymerization of 1,3-butadiene. We used the ternary catalytic system neodymium versatate/diethylaluminum chloride/triisobutylaluminum (NdV3/DEAC/TIBA) with 0.5 mM NdV3/100 g Bd, NdV3 : DEAC = 1 : 9 mol : mol, and TIBA = 25, 50, 100, and 200 mM. The number-average molecular weight (Mn), weight-average molecular weight (Mw), and polydispersity index (PDI) were analyzed by GPC; the rheological properties were analyzed by DMA. The formulations were prepared with carbon black (IRB6) as reinforcing filler and the mechanical properties were compared to behavior of the different elastomeric compounds. The elastomeric compounds were characterized by their rheological properties, tensile strength, abrasion resistance, tear strength, permanent set, resilience, and fatigue properties. The highcis-1,4 polybutadiene (highcis-1,4-BR) was obtained with a percentage ofcis-1,4 ≥97%. The weight-average molecular weight (Mw) was from 150 × 103to 900 × 103 g/mol and polydispersity index (PDI) was from 3.1 to 5.1. This work is based on evaluation of the effect of the catalyst system on the final properties of the synthesized polybutadiene.

Highlights

The neodymium catalyst causes high catalytic activity during the polymerization of dienes; good control has not been achieved with regard to molecular weight and molecular weight distribution, which is attributed to the multiple active sites present in this catalyst
The influence of the initial reaction temperature and the addition of alkyl aluminum play an important role in monomer conversion and polymer molecular weight
The percentage of conversion of high cis-1,4-BR with ternary catalyst system is shown in Figure 1 (0.5 mM NdV3/100 g Bd, NdV3 : diethylaluminum chloride (DEAC) = 1 : 9 mol : mol, and TIBA = 25, 50, 100, and 200 mM)

Summary

Introduction

The neodymium catalyst causes high catalytic activity during the polymerization of dienes; good control has not been achieved with regard to molecular weight and molecular weight distribution, which is attributed to the multiple active sites present in this catalyst. High cis-1,4-BR is an elastomer essential for tire manufacturing because of the advantages obtained by adding this substance to styrene-butadiene rubber (SBR) and polyisoprene, such as outstanding low wear resistance, rolling resistance, high elasticity even at low temperatures, high flexibility to cracking, fatigue resistance, and improved adhesion to metals. This behavior is important for use in many parts of radial and bias tires [9,10,11]. The high stereoregularity provides excellent dynamic mechanical properties, especially higher tensile strength, lower heat buildup, and better abrasion resistance [15,16,17]

Experimental

Catalyst Preparation

Results and Discussion

Conclusions