Terminal-Functionalized Polymer Silica Dispersion
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Solution Overview
Problem
Silica filler dispersion in rubber compositions is challenging, affecting the performance of tire treads in terms of rolling resistance and fuel economy, and existing methods do not adequately address cold flow resistance and filler dispersion issues.
Innovation Solution
A terminal-functionalized polymer is developed by reacting a randomized polymer chain comprising conjugated diene and vinyl aromatic monomers with a silicon-containing functionalizing agent, improving filler dispersion and cold flow resistance when combined with silica filler and a cure package in rubber compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silica filler is added to rubber composition to decrease rolling resistance, then fuel economy is improved, but filler dispersion becomes difficult
Solution Approach 1:
A silane-modified polymer is introduced as an intermediary substance between the silica filler and the rubber matrix. The silane groups on the polymer surface interact with silica filler particles, while the polymer chain integrates with the rubber matrix, thereby improving filler dispersion and reducing aggregation. This mediator resolves the contradiction by enabling good dispersion without compromising the rolling resistance reduction benefit.
Solution Approach 2:
The polymer is chemically modified by introducing silane functional groups, changing its surface properties and chemical composition. This parameter change enables the polymer to interact with both silica filler and rubber matrix, improving dispersion stability while maintaining the energy loss reduction achieved through silica addition.
2Loss of energy
If conventional polymer is used with silica filler, then rolling resistance is reduced, but cold flow resistance is insufficient
Solution Approach 1:
The invention creates a composite material system consisting of silane-modified polymer, silica filler, and rubber matrix. The silane-modified polymer acts as a coupling agent that strengthens the interface between filler and matrix, thereby improving cold flow resistance (a measure of molecular chain mobility and processing stability) while maintaining the low rolling resistance property provided by silica reinforcement.
3Loss of energy
If conventional polymer is used with silica filler, then rolling resistance is reduced, but filler dispersion remains poor
Solution Approach 1:
The silane-modified polymer serves as a mediator that compatibilizes the silica filler and rubber matrix. The silane groups bond to silica surface hydroxyl groups, while the polymer chains entangle with the rubber matrix, creating a stable interface that prevents filler aggregation and ensures uniform dispersion throughout the composition, thereby resolving the dispersion issue while preserving the energy efficiency benefit.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The terminal-functionalized polymer enhances filler dispersion and cold flow resistance, leading to improved tire tread performance and fuel efficiency by effectively integrating silica filler, as demonstrated by increased bound rubber content and reduced rolling resistance.
Implementation Method 1
reacting the live end of a randomized polymer chain comprising a conjugated diene monomer and a vinyl aromatic monomer with a functionalizing agent comprising a compound having formula (V)
Data Source
AI summary
Disclosed herein are terminal-functionalized polymers functionalized with silicon-containing functionalizing agents, rubber compositions including the polymers, methods for improving the cold flow resistance of a polymer, methods for improving the filler dispersion of a silica-filled rubber composition, and processes for preparing the terminal-functionalized polymer.