Silica and Carbon Black Matrix-Filler Interactions in SBR/BR an SBR/NR
Blends as Studied by NMR Crosslink Density Analysis
1 IIC Dr. Kuhn GmbH&Co KG, Langental 18, 66440 Blieskastel, Germany.
2 Linglong Tires, Zhaojuan, Shandong, China
3 Qingdao University of Science&Technology, Key Lab of Rubber&Plastics, Qingdao, China.
SBR/BR- and SBR/NR Blends are of great importance in rubber and care tire industry. The
understanding of mechanical, thermal and aging behavior as well as the development of new blends with tailored properties require a deeper understanding of both, the polymer components and interaction between the polymer matrix and Silica or Carbon Black filler. During the past 10 years, a significantly increasing number of publications in well reputed scientific journals can be found on the application of high and low field NMR as a tool to explore the chemical structure and molecular dynamics of elastomers. In the present work, a large number of SBR/BR and SBR/NR blends with different polymer composition and different Silica and Carbon Black filler contents have been prepared. Low field NMR investigations with regard to T1 and XLD measurements using the IIC XLDS-15 crosslink density analyzer have been carried out at a sample temperature of 80°C. Both, T1 and T2 relaxation times as well as XLD data show a strong dependency on the polymer base ratio, as well as on the Silica and Carbon Black filler content of the uncured and cured compounds.
The results yield clearly:
- The mobility of the hydrocarbon chain network is strongly affected by the polymer
- The mobility of the hydrocarbon chains of the uncured rubber blend as well as the cured
rubber network depends significantly on the type and amount of filler.
- Silica filler show a much stronger effect on the network mobility in comparison to Carbon
- The Bound Rubber component in filled SBR/BR resp SBR/NR blends is significantly higher
for Silica filled than for Carbon Black filled blends.
- Bound Rubber is mainly formed by the BR resp NR component of the blend.
- The Bound Rubber effect can be observed on both, uncured and cured blends.
- Cross-links are mainly formed by the BR resp NR component while the contribution of SBR
to the cross-linked network is comparably low.
- Low field NMR Cross-link density analysis is a very useful tool for a deeper understanding of matrix-filler interactions on a molecular level.
- Detailed results and interpretation of the network mobility and molecular dynamics of the hydrocarbon chains will be presented.
A Replacement Compound for Carbon Black-filled Passenger Car Tire Side Wall Based on a Silanized Silica Nanofiller
Zainudin Umar, Ali Ansarifar*
Carbon black is a major ingredient of tire compounds. However, carbon black is toxic and there is a considerable health risk associated with its use in rubber. This study developed a new natural rubber/polybutadiene (NR/BR) rubber blend for passenger car tire side wall, using precipitated amorphous white silica. The surface of silica had been pre-treated with bis(3-triethoxysilylpropyl) tetrasulfide (TESPT). TESPT is a bifunctional organosilane and chemically bonds silica to rubber. The rubber was primarily cured by using sulfur in TESPT, and the cure was optimized by adding sulfenamide accelerator, zinc oxide activator, and elemental sulfur. The new rubber blend had higher tear strength, longer cyclic fatigue life, and better resistance to abrasion than the carbon black-filled NR/BR rubber compound currently in use in some passenger car tires. Moreover, it was essential for the rubber reactive tetrasulfane groups of TESPT to react fully with the rubber chains in order to take maximum advantage of the reinforcing effect of the filler on the mechanical properties of the rubber blend. In the absence of full reaction between the two, the mechanical properties of the silica-filled rubber blend were considerably inferior to those of the carbon black-filled compound. In the final analysis, the overall costs of the chemical curatives was reduced by almost 27%.
COST ENGINEERING in AUTOMATIVE INDUSTRY
Target Product Cost Calculation of Automotive Tires
Voith Engineering Services GmbH & Co KG Meitnerstraße 11, 70563 Stuttgart, Germany (Yasemin.Atsiz@voith.com)
Anahtar kelimeler: Cost Engineering
As it is known well cost engineering began in 1950’s and now days is becoming very important in the industry. One key objective of cost engineering is to arrive at accurate cost estimates and schedules and to avoid cost overruns and schedule slips. Cost engineering goes beyond preparing cost estimates and schedules by helping manage resources and supporting assessment and decision making.
This article presents an approach of how product costs of rubber parts can be calculated and can be optimized. Here will be as a key study the product cost building and optimization of tyres discussed.
This leads to the proposition of applying tyre product costing methods to industries. Hence, proposals on how product cost is calculated to the automotive industry are presented as the focus of this article. Gaps and challenges for tyre costing are identified and corresponding future direction is suggested.
The most obvious perception is that engineering addresses technical issues such as the physical design of the tyre structure or system. However, beyond the physical manifestation of a design of a tyre structure, there are other dimensions to consider such as raw material costs, machine cycle time, and other resources that were invested in the target cost creation of the product manufacturing.
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