Functionalized High Cis-1,4-Polybutadiene Rubber Stiffness
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Solution Overview
Problem
High cis-1,4-polybutadiene rubber compositions used in tire apexes and golf ball cores face challenges in achieving high stiffness and low hysteresis, leading to inconsistent performance and manufacturing difficulties due to exothermic reactions during vulcanization.
Innovation Solution
Functionalizing high cis-1,4-polybutadiene rubber with carboxylic acid groups, specifically pendant groups of the formula —S-A-COOH, to enhance its interaction with α,β-ethylenically unsaturated carboxylic acids like zinc diacrylate, resulting in improved stiffness and reduced hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional high cis-1,4-polybutadiene rubber is used in tire apexes and golf ball cores, then basic rubber properties are maintained, but stiffness is insufficient and hysteresis is high leading to inconsistent performance
Solution Approach 1:
The patent modifies the chemical structure of high cis-1,4-polybutadiene rubber by introducing carboxylic acid functional groups through reaction with dicarboxylic acids or their derivatives. This chemical parameter change enables stronger interaction with zinc diacrylate filler, resulting in improved stiffness and reduced hysteresis while maintaining performance consistency across different applications.
Solution Approach 2:
The patent creates a composite rubber composition by combining functionalized high cis-1,4-polybutadiene rubber with zinc diacrylate filler. The carboxylic acid groups on the rubber chains form strong complexes with the zinc diacrylate, creating a composite material that exhibits enhanced stiffness and lower hysteresis compared to conventional rubber formulations.
2Ease of manufacture
If conventional rubber compositions are used, then manufacturing is simpler, but exothermic reactions during vulcanization cause manufacturing difficulties
Solution Approach 1:
The functionalization of the rubber with carboxylic acid groups changes the chemical reactivity parameters of the rubber composition. This modification reduces the intensity of exothermic reactions during vulcanization by altering the interaction mechanisms between rubber, filler, and curing agents, thereby eliminating manufacturing difficulties while maintaining ease of production.
3Strength
If zinc diacrylate is added to conventional high cis-1,4-polybutadiene rubber, then filler-rubber interaction improves, but compatibility is insufficient leading to suboptimal stiffness and hysteresis
Solution Approach 1:
The patent introduces carboxylic acid functional groups on the rubber chains, which fundamentally changes the chemical interaction parameters between rubber and zinc diacrylate. The carboxylic acid groups form strong coordinate bonds with zinc ions, creating a more compatible and effective filler-rubber system that achieves superior stiffness and reduced hysteresis.
Solution Approach 2:
The carboxylic acid groups act as chemical intermediaries that mediate the interaction between the hydrocarbon rubber chains and the inorganic zinc diacrylate filler. These functional groups provide binding sites that facilitate strong adhesion and efficient stress transfer, optimizing the filler-rubber interface for improved mechanical properties.
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 functionalized rubber compositions exhibit improved stiffness and lower hysteresis, leading to better performance in tire apexes and golf ball cores, with enhanced manufacturing efficiency and reduced exothermic reactions.
Implementation Method 1
Functionalizing high cis-1,4-polybutadiene rubber with carboxylic acid groups, specifically pendant groups of the formula —S-A-COOH, to enhance its interaction with α,β-ethylenically unsaturated carboxylic acids like zinc diacrylate
Data Source
AI summary
It has been found that carboxylic acid functionalized high cis-1,4-polybutadiene rubber which is comprised of polybutadiene rubber chains having a cis-1,4-microstructure content of at least 90 percent has much better interaction with metal salts of α,β-ethylenically unsaturated carboxylic acids, such as zinc diacrylate or zinc dimethacrylate. This results in such rubber compositions being stiff while still exhibiting a lower level of hysteresis. These characteristics are beneficial when used in manufacturing tire apex compositions, in manufacturing golf ball cores, and in a wide variety of other applications. Such rubber compositions can be used as substitutes for thermoplastic elastomers in many applications.