Silane-Mediated Stabilization of Branched Elastomer Viscosity
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Solution Overview
Problem
Hydrolytically cleavable bonds in branched elastomeric polymers lead to unstable storage behavior, characterized by variable polymer viscosity over time and temperature, which is undesirable for commercial applications.
Innovation Solution
The use of a specific multi(vinyl or butadienyl)aminosilane compound as a branching agent and a vinylsilane compound as a stabilizer during the polymerization of conjugated dienes, such as butadiene and isoprene, in the presence of an organo-alkali metal compound, to stabilize the polymer viscosity and improve storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If hydrolytically cleavable bonds are introduced into the polymer backbone to create branched elastomeric polymers, then the polymer exhibits improved fuel efficiency and reduced hysteresis loss, but the polymer shows unstable storage behavior with variable viscosity over time and temperature
Solution Approach 1:
A silane-based coupling agent is introduced as an intermediary substance that mediates between the polymer chains to form stable crosslinks. The coupling agent contains hydrolyzable groups that react with hydroxyl groups on polymer chains, creating stable Si-O-Si crosslinked structures that prevent unwanted hydrolytic cleavage while maintaining the desired branched architecture for low hysteresis loss
Solution Approach 2:
The crosslinking density and molecular weight of the polymer are optimized to achieve the desired balance between fuel efficiency and storage stability. By controlling parameters such as the amount of coupling agent, moisture content during processing, and polymerization conditions, the invention achieves optimal performance with reduced hysteresis loss while maintaining stable viscosity during storage
2Stability of the object's composition
If the coupling rate is reduced to improve storage stability, then the polymer viscosity becomes more stable over time, but the fuel efficiency and hysteresis loss performance deteriorates
Solution Approach 1:
The invention optimizes the coupling rate parameter to a specific range that simultaneously achieves stable storage viscosity and low hysteresis loss. By precisely controlling the coupling rate and crosslinking density, the patent finds the optimal balance point where storage stability is maintained while fuel efficiency performance is preserved
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 effectively stabilizes polymer viscosity, reducing temperature dependence and maintaining stability over time, thereby enhancing the commercial viability of the polymer.
Implementation Method 1
In the presence of nucleophiles such as water, alcohol etc., the bonds may be cleaved as follows... To prevent such a hydrolytic cleavage, water scavengers can be added to the polymer formulation
Implementation Method 2
Hydrolytically cleavable bonds within the polymer backbone can, when actually cleaved, lead to a reduction of polymer viscosity... To prevent such a hydrolytic cleavage
Data Source
AI summary
The present invention relates to a process for preparing a branched elastomeric polymer by polymerization of a conjugated diene in the presence of a specific branching agent and a specific stabilizing compound. The branched elastomeric polymer exhibits improved storage stability, as reflected by a constant, or less variable, polymer viscosity over time and with reduced temperature dependence.