Chain End Modified Elastomer for Tire Tread Hysteresis
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Solution Overview
Problem
Existing methods for reducing hysteresis loss in vulcanized elastomeric polymers, such as those used in tire treads, face challenges due to incomplete distribution of sulfanylsilane coupling agents in highly viscous rubber compounding environments, leading to inefficient interaction with polymer chains and fillers.
Innovation Solution
A chain end modified elastomeric polymer is created by reacting a living anionic elastomeric polymer with a silane-sulfide modifier, ensuring complete interaction with fillers and unsaturated segments, thereby reducing hysteresis loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfanylsilane coupling agents are used in highly viscous rubber compounding environments, then interaction with polymer chains and fillers occurs, but distribution is incomplete leading to inefficient interaction
Solution Approach 1:
The sulfanylsilane coupling agent is incorporated into the polymer chain during the polymerization process itself, before the compounding stage. This preliminary action ensures that the coupling agent is already uniformly distributed within the polymer matrix, eliminating the distribution problems that occur when adding coupling agents to highly viscous rubber compounding environments later.
Solution Approach 2:
The invention merges the polymerization process with the coupling agent incorporation step. By combining these two operations into a single integrated process, the coupling agent becomes an integral part of the polymer chain structure, ensuring both uniform distribution and effective interaction with fillers during subsequent vulcanization.
2Ease of manufacture
If free polymer chain ends are present in vulcanized elastomeric polymers, then polymerization is simpler, but hysteresis loss increases
Solution Approach 1:
The coupling agent is incorporated into the polymer chain ends during the polymerization process itself, performing the chain end modification in advance. This preliminary action eliminates free chain ends before vulcanization, preventing hysteresis loss without requiring separate post-polymerization treatment steps.
Solution Approach 2:
The living anionic polymerization system automatically incorporates the sulfanylsilane coupling agent into the chain ends through its inherent reactivity. The polymerization system serves its own chain end modification needs without requiring external intervention or additional processing steps.
3Loss of energy
If chain end modification is performed to reduce hysteresis loss, then rolling resistance improves, but processability may be affected
Solution Approach 1:
The invention merges chain end modification with the polymerization process itself. By incorporating the sulfanylsilane coupling agent during polymerization, the modification occurs in-situ without requiring separate processing steps, thereby maintaining processability while achieving reduced hysteresis loss and improved rolling resistance.
Solution Approach 2:
The invention changes the timing parameter of chain end modification from post-polymerization to during-polymerization. This parameter change allows the modification to occur under controlled polymerization conditions, maintaining polymer processability while achieving the desired reduction in hysteresis loss for improved rolling resistance.
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 approach results in vulcanized elastomeric compositions with lower tan δ at 60° C. values, improving rolling resistance and maintaining good physical properties like abrasion resistance and tensile strength.
Implementation Method 1
A chain end modified elastomeric polymer is created by reacting a living anionic elastomeric polymer with a silane-sulfide modifier
Implementation Method 2
The polymer 'end caps' are reactive with unsaturated portions of the elastomeric polymer backbone and/or with fillers or other components present in an elastomeric composition
Data Source
AI summary
A vulcanized elastomeric composition includes (i) a polymer reaction product of an anionic elastomeric polymer and a silane-sulfide modifier and (ii) a second elastomeric polymer different from the polymer reaction product such that the polymer reaction product comprises at least 30 weight percent of a total amount of the polymer reaction product and the second elastomeric polymer. Methods are described for making the polymer reaction product, their use in preparing vulcanized elastomeric compositions, and articles made from such compositions, including pneumatic tires, tire treads, belts, and the like.