Terminal Nitrogen-Modified Diene Polymer for Tire Tread
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Solution Overview
Problem
Pneumatic tires face challenges in achieving balanced improvements in low hysteresis loss property and abrasion resistance, which are essential for reducing energy consumption and environmental impact, while maintaining good processability and filler dispersibility.
Innovation Solution
A conjugated diene-based polymer with a nitrogen-containing group at its terminal is produced through polymerization and modification, combined with silica and a crosslinking agent to create a polymer composition that enhances filler dispersibility and vulcanized rubber properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional conjugated diene-based polymers are used to reduce hysteresis loss, then low fuel consumption performance is improved, but abrasion resistance deteriorates
Solution Approach 1:
The invention applies local quality by introducing specific nitrogen-containing groups (amino, hydrazino, or azo groups) at the terminal positions of the conjugated diene polymer chains. This localized functional group placement improves filler interaction and dispersibility without altering the bulk polymer structure, thereby maintaining low hysteresis loss while enhancing abrasion resistance through improved filler-rubber interaction.
Solution Approach 2:
The invention creates a composite effect by combining the conjugated diene polymer with fillers (such as silica or carbon black) where the terminal nitrogen-containing groups facilitate stronger interfacial bonding. This composite structure allows the filler network to contribute to abrasion resistance while the polymer matrix maintains its low hysteresis loss characteristics.
2Strength
If filler content is increased to improve abrasion resistance, then durability is improved, but energy loss increases due to poor filler dispersibility
Solution Approach 1:
The terminal nitrogen-containing groups act as intermediaries between the filler particles and the polymer matrix. These groups improve filler dispersibility by reducing filler aggregation and enhancing interfacial adhesion, allowing for effective filler networking at lower concentrations. This mediator effect ensures that fillers are uniformly distributed, maintaining abrasion resistance while minimizing energy loss from poor dispersibility.
3Ease of manufacture
If terminal modification is applied to improve filler dispersibility, then processing is improved, but polymer structure complexity increases
Solution Approach 1:
The invention applies preliminary action by incorporating the nitrogen-containing groups during the polymerization process itself, rather than requiring post-polymerization modification steps. The terminal groups are formed as the polymer chains are being synthesized, ensuring uniform distribution and proper functionalization. This preliminary incorporation simplifies the overall manufacturing process while achieving the desired filler dispersibility and processing improvements.
Data Source
AI summary
A conjugated diene-based polymer comprising a structural unit derived from a conjugated diene compound and having, at a terminal of the polymer, at least one nitrogen-containing group represented by formula (1) is used. In formula (1), R1 is a hydrocarbyl group, and the symbol "*" is a bonding site.