Bifunctionalized Elastomer End-Group Modification for Tire Tread
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Solution Overview
Problem
Current rubbery polymers used in tire tread compositions exhibit inconsistent viscoelastic properties, leading to suboptimal rolling resistance and traction characteristics due to inadequate interaction with fillers like carbon black and silica, which affects the physical properties of tires.
Innovation Solution
The synthesis of bifunctionalized elastomers through the reaction of living anionic elastomeric polymers initiated with a functional initiator and terminated with a specific functional polymerization terminator, enhancing the affinity of the polymers for fillers by modifying the end-groups, thereby improving polymer-filler interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blends of various types of synthetic and natural rubber are utilized to achieve inconsistent viscoelastic properties for tire tread rubber compositions, then rolling resistance and traction characteristics can be adjusted, but the complexity of the rubber composition increases and processing becomes more difficult
Solution Approach 1:
The patent modifies the chemical structure of the polymer by introducing functional groups (aminobenzophenone, tin coupling agents) at the chain ends, which changes the interaction parameters between polymer and filler. This allows tuning of viscoelastic properties through chemical modification rather than physical blending, resolving the contradiction by maintaining property adaptability while simplifying composition complexity
Solution Approach 2:
The patent uses coupling agents (aminobenzophenone, tin compounds) as intermediaries between the polymer chain ends and the filler surfaces. These intermediaries facilitate controlled interaction with fillers like carbon black and silica, enabling precise adjustment of viscoelastic properties without requiring complex rubber blends, thus reducing composition complexity while maintaining versatility
2Reliability
If rubbery polymers with lower rebound physical property (higher hysteresis) are used to increase wet skid resistance, then traction characteristics improve, but rolling resistance increases
Solution Approach 1:
The patent applies functional modification locally at the polymer chain ends rather than throughout the entire polymer structure. By concentrating the functional groups (aminobenzophenone, tin coupling agents) at the termini, the patent creates localized interaction zones with fillers that selectively enhance traction characteristics while maintaining lower hysteresis in the bulk polymer, thus improving wet skid resistance without significantly increasing rolling resistance
Solution Approach 2:
The patent creates a composite structure where functionalized polymer chains are combined with specific fillers (carbon black, silica) in controlled ratios. The functional groups at chain ends create strong interfacial bonding with fillers, forming a composite material that optimizes the balance between traction and rolling resistance by distributing stress at the filler-polymer interface rather than through bulk hysteresis
3Loss of energy
If the affinity of filler for rubbery polymer is improved to enhance polymer-filler interaction, then hysteresis and rolling resistance are reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent performs preliminary functionalization of the polymer chain ends during the polymerization process itself. By incorporating functional initiators or terminators (aminobenzophenone, tin coupling agents) at the chain ends during synthesis, the patent pre-equips the polymer with filler-interacting groups before compounding, eliminating the need for separate post-polymerization modification steps and simplifying the overall manufacturing process while achieving reduced hysteresis
Solution Approach 2:
The patent replaces mechanical mixing and physical bonding mechanisms with chemical bonding mechanisms. By introducing functional groups that form chemical bonds (coordination bonds, covalent bonds) with filler surfaces, the patent substitutes mechanical dispersion processes with chemically-driven affinity, reducing hysteresis through stronger interfacial bonding while simplifying processing by eliminating the need for extensive mechanical mixing to achieve homogeneous dispersion
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 results in reduced polymer hysteresis, lower rolling resistance, and improved traction characteristics by enhancing the dispersion and interaction of fillers within the rubber matrix, leading to better tire performance.
Implementation Method 1
The synthesis of bifunctionalized elastomers through the reaction of living anionic elastomeric polymers initiated with a functional initiator and terminated with a specific functional polymerization terminator
Implementation Method 2
modifying the end-groups, thereby improving polymer-filler interaction
Implementation Method 3
enhancing the affinity of the polymers for fillers by modifying the end-groups, thereby improving polymer-filler interaction
Implementation Method 4
enhancing the dispersion and interaction of fillers within the rubber matrix
Data Source
AI summary
A bifunctionalized elastomer comprising the reaction product of 1) a living anionic elastomeric polymer initiated with a functional initiator and 2) a functional polymerization terminator is disclosed. The living anionic elastomeric polymer initiated with the functional initiator is of formula AYLi where Y is a divalent polymer radical, Li is a lithium atom bonded to a carbon atom of Y, and A is an amine-containing radical.