Imine-Functionalized Polydienes for Low Hysteresis Rubber
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Solution Overview
Problem
Current methods for reducing hysteresis in rubber vulcanizates used in tire components are unpredictable and often ineffective, as the suitability of functional groups for reducing hysteresis varies with different polymer types, and existing catalyst systems do not consistently produce polymers with desirable properties such as low hysteresis, high tensile strength, and fatigue resistance.
Innovation Solution
The method involves polymerizing conjugated diene monomers using a lanthanide-based catalyst system to form reactive polymers, which are then functionalized with an imine compound containing a protected thiol group, resulting in cis-1,4-polydienes with reactive chain ends that can interact with filler particles to reduce hysteresis and improve mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If functionalized polymers are used to reduce hysteresis, then energy loss is reduced, but the effectiveness is unpredictable and varies with polymer type
Solution Approach 1:
The patent changes the chemical parameter of the functional group from generic types to specifically imine compounds containing protected thiol groups. This parameter change provides consistent and predictable hysteresis reduction across different polymer types, resolving the reliability issue while maintaining energy loss reduction.
Solution Approach 2:
The imine compound with protected thiol group acts as an intermediary that mediates between the polymer chain ends and filler particles. This specific functional group structure provides consistent interaction mechanisms, making the hysteresis reduction effect predictable and reliable across different polymer systems.
2Productivity
If different catalyst systems are used to polymerize diene monomers, then polymerization speed varies, but the resulting polymer properties such as hysteresis and tensile strength become inconsistent
Solution Approach 1:
The patent changes the catalyst system parameter from various types (titanium, cobalt, nickel) to specifically lanthanide-based catalysts. This parameter change simultaneously achieves high polymerization productivity and consistent production of cis-1,4-linkage polymers with desirable mechanical properties and low hysteresis.
Solution Approach 2:
The lanthanide-based catalyst system provides multi-functionality by simultaneously enabling fast polymerization kinetics and producing polymers with consistent cis-1,4 microstructure. This universal catalyst achieves both high productivity and manufacturing precision for the desired polymer properties.
3Strength
If free polymer chain ends are present in crosslinked rubber networks, then vulcanization proceeds, but hysteresis increases due to energy loss
Solution Approach 1:
The patent extracts or removes the harmful effect of free polymer chain ends by introducing imine compounds with protected thiol groups that interact with these chain ends. This takes out the source of hysteresis while preserving the necessary crosslinking for vulcanization, reducing energy loss without sacrificing strength.
Solution Approach 2:
The patent converts the harmful free polymer chain ends into beneficial structures by having them interact with imine compounds containing protected thiol groups. This transformation eliminates the hysteresis-causing effect while maintaining or enhancing the crosslinked network structure, turning a disadvantage into an advantage.
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
This approach consistently produces tire components with reduced hysteresis, improved tensile properties, and enhanced fatigue resistance, making them suitable for use in tire sidewalls and treads.
Implementation Method 1
Lanthanide-based catalyst systems are known to be useful for polymerizing conjugated diene monomer to form polydienes having a high content of cis-1,4-linkage
Implementation Method 2
reacting the reactive polymer with an imine compound containing a protected thiol group
Implementation Method 3
the functional group may reduce the number of free polymer chain ends via interaction with filler particles
Data Source
AI summary
A method for preparing a functionalized polymer, the method comprising the steps of: (i) polymerizing monomer to form a reactive polymer, and (ii) reacting the reactive polymer with an imine compound containing a protected thiol group.