End-Modified Conjugated Diene Polymer for Silica Dispersion
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Solution Overview
Problem
Conjugated diene rubber compositions with silica reinforcement face challenges in dispersibility and hysteresis loss due to silica's hydrophilic nature, requiring additional silane coupling agents to enhance silica-rubber bonding and reduce rolling resistance.
Innovation Solution
A method is developed to synthesize a modified conjugated diene polymer by reacting a compound with an organometallic compound to create an initiator, followed by polymerization and coupling with aminosilane, resulting in a polymer with silyl groups substituted by alkoxy groups and nitrogen atoms, which improves silica dispersion and bonding within the rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica is used as a reinforcement in conjugated diene rubber, then wet skid resistance is improved, but dispersibility of silica in rubber deteriorates due to low affinity between hydrophilic silica surface and hydrophobic rubber
Solution Approach 1:
The invention modifies the chemical parameters of the rubber molecule by introducing functional groups (amine groups) at the chain ends through controlled polymerization and subsequent reaction with aminosilane compounds. This changes the surface chemistry of the rubber to be more compatible with silica, improving dispersibility while maintaining the reinforcement benefits
Solution Approach 2:
The invention uses aminosilane compounds as intermediary substances that bridge the hydrophobic rubber and hydrophilic silica. The silyl groups bond to silica surface while the amine groups interact with rubber, creating a compatible interface that improves silica dispersion without requiring additional silane coupling agents
2Stability of the object's composition
If additional silane coupling agent is used to improve silica dispersibility, then dispersability of silica is improved, but device complexity and manufacturing process complexity increase
Solution Approach 1:
The invention combines multiple functions into the polymer chain ends themselves - the amine groups serve both as compatibility modifiers for silica and as reactive sites for direct bonding. This eliminates the need for separate silane coupling agent addition steps, simplifying the manufacturing process while achieving the same dispersibility improvement
Solution Approach 2:
The rubber polymer itself is modified to provide the functionality previously requiring external additives. The end-modified polymer chains self-organize and self-bond with silica particles through their built-in amine groups, eliminating the need for additional coupling agents and reducing process complexity
3Loss of energy
If silica is used as reinforcement, then hysteresis loss is reduced, but additional processing steps are required to bond silica to rubber
Solution Approach 1:
The invention performs preliminary modification of the rubber polymer chains during the polymerization process itself, introducing amine groups at the chain ends before mixing with silica. This pre-preparation eliminates the need for subsequent coupling agent addition and bonding steps, maintaining low hysteresis loss while improving manufacturing efficiency
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 modified rubber composition exhibits enhanced heat generation, tensile strength, abrasion resistance, and wet skid resistance when mixed with silica, leading to reduced fuel consumption and improved tire performance.
Implementation Method 1
reacting a compound represented by the following Formula 1 with an organometallic compound to prepare an initiator
Implementation Method 2
polymerizing a conjugated diene monomer, or the conjugated diene monomer and a comonomer thereof with the initiator to prepare an active polymer
Implementation Method 3
reacting the active polymer with aminosilane to prepare a modified conjugated diene polymer
Data Source
AI summary
Disclosed are a method for preparing a conjugated diene polymer including synthesizing an initiator having an anionic end containing an amine and a cationic end containing an alkali metal, polymerizing a combination of an aromatic vinyl monomer using the initiator to synthesize a polymer having a modified end, coupling or reacting the polymer with a compound having at least one silyl group substituted by an alkoxy group and a nitrogen atom to prepare a modified conjugated diene polymer having one end containing amine and the other end containing silyl group substituted by one or more alkoxy group and a nitrogen atom, and a rubber composition comprising the conjugated diene polymer and silica as a reinforcing agent and thus exhibiting superior heat generation, tensile strength, abrasion resistance and wet skid resistance.