Polyfunctionalized High-Cis Polybutadiene for Processability
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Solution Overview
Problem
High-cis conjugated diene-based polymers exhibit excellent mechanical properties but suffer from poor processability and compatibility with reinforcing materials due to high viscosity and cold flow, leading to degraded mechanical and dynamic properties in rubber compositions.
Innovation Solution
A rubber mixture comprising a high molecular weight polymer functionalized with specific compounds and a low molecular weight polymer, both derived from conjugated diene-based monomers, is prepared to enhance processability and dispersibility of reinforcing materials, improving mechanical and dynamic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-cis conjugated diene-based polymer is used to improve mechanical properties, then wear resistance and crack resistance are improved, but processability deteriorates due to high viscosity
Solution Approach 1:
The patent segments the polymer into two distinct molecular weight fractions: a high molecular weight fraction (Mw ≥ 100,000) providing mechanical strength and a low molecular weight fraction (Mw < 100,000) providing processability. This segmentation allows each fraction to fulfill its specific function independently, resolving the contradiction between strength and ease of manufacture
Solution Approach 2:
The patent changes the molecular weight parameter by producing a bimodal distribution with specific weight ratios (85:15 to 98:2 of high to low molecular weight fractions). This parameter change enables the polymer to exhibit both high mechanical properties from the high molecular weight fraction and good processability from the low molecular weight fraction
2Strength
If high-cis conjugated diene-based polymer is used to improve mechanical properties, then wear resistance is improved, but compatibility with reinforcing agent deteriorates
Solution Approach 1:
The patent applies local quality by having different molecular weight fractions perform different functions: the high molecular weight fraction provides wear resistance while the low molecular weight fraction provides compatibility with reinforcing agents. This local differentiation of function within the polymer structure resolves the contradiction between wear resistance and compatibility
3Strength
If high-cis conjugated diene-based polymer is used to improve mechanical properties, then crack resistance is improved, but storage stability deteriorates due to high cold flow
Solution Approach 1:
The patent segments the polymer into high and low molecular weight fractions where the high molecular weight fraction provides crack resistance and the low molecular weight fraction reduces cold flow. This segmentation resolves the contradiction between crack resistance and storage stability by having each fraction address a specific issue
Data Source
AI summary
Provided is a rubber mixture, which includes a unit structure derived from a first conjugated diene-based monomer and is functionalized with at least one of the compounds represented by Formulas 1 to 6; and a second low molecular weight rubber polymer, which includes a unit structure derived from a second conjugated diene-based monomer and is functionalized with at least one of the compounds represented by Formulas 1 to 6.