Dynamic Rubber Composition With Urethane Dispersion for Lower Payne Effect
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Solution Overview
Problem
Conventional rubber compositions with reinforcing fillers exhibit undesirable dynamic properties due to the Payne effect, characterized by nonlinearity and stiffening under dynamic stresses, which limits their suitability for applications requiring improved dynamic performance without compromising static properties.
Innovation Solution
A rubber composition is developed by thermomechanical blending of an elastomer with a reinforcing filler and precursors of a polymer bearing urethane groups, followed by crosslinking, which results in a fine and homogeneous dispersion of the polymer within the elastomer matrix, minimizing the Payne effect while maintaining static properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If reinforcing fillers such as carbon black and silica are added to elastomers to improve mechanical properties, then strength and stiffness are enhanced, but the Payne effect occurs causing nonlinearity and stiffening under dynamic stresses
Solution Approach 1:
The invention changes the chemical and physical parameters of the rubber composition by incorporating a specific polyurethane content (5-50 phr) with defined molecular weight and functionality. This parameter change modifies the interaction between the elastomer and reinforcing fillers, reducing the Payne effect while maintaining mechanical strength. The polyurethane acts as a modifying agent that alters the filler-elastomer interface properties.
Solution Approach 2:
The invention creates a composite material system combining elastomer, reinforcing fillers (carbon black/silica), and polyurethane in specific proportions. This composite approach allows the polyurethane to mediate between the fillers and elastomer matrix, reducing harmful filler-filler interactions while preserving reinforcement benefits. The composite structure enables simultaneous optimization of both static mechanical properties and dynamic performance.
2Reliability
If the ratio of storage moduli G'0.5%/G'20% is reduced to minimize the Payne effect, then dynamic properties are improved, but static properties such as stiffness and strength may be compromised
Solution Approach 1:
The invention optimizes multiple parameters simultaneously: polyurethane content (5-50 phr), polyurethane molecular weight (1000-10000 g/mol), and polyurethane functionality (2-6). By carefully adjusting these parameters, the composition achieves a balance where the polyurethane provides enough flexibility to reduce the Payne effect (lowering G'0.5%/G'20% ratio) while maintaining sufficient structural integrity for static strength requirements.
Solution Approach 2:
The polyurethane distributes locally within the rubber composition, creating regions with modified properties. These local polyurethane-rich zones act as stress distributors that reduce filler aggregation and minimize the Payne effect, while the overall composition maintains the necessary stiffness and strength through the elastomer matrix and filler network.
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 composition achieves a reduced Payne effect across a wide temperature range, enhancing dynamic properties while preserving static properties, making it suitable for dynamic applications such as antivibration supports and elastic articulations.
Implementation Method 1
thermomechanical blending of an elastomer with a reinforcing filler and precursors of a polymer bearing urethane groups
Implementation Method 2
followed by crosslinking, which results in a fine and homogeneous dispersion of the polymer within the elastomer matrix
Data Source
AI summary
The invention relates to a rubber composition for a mechanical member with a dynamic function, to a process for preparing this composition, to such a member and to a use of a polymer bearing urethane functions. The composition is based on at least one elastomer and comprises a reinforcing filler and said polymer dispersed in the elastomer, the composition comprising the product of an in situ thermomechanical blending reaction of the elastomer with the filler, precursors of the polymer and a chain extender. According to the invention, the composition has a ratio G′ 0.5%/G′ 20% of storage moduli G′ relative to the complex shear moduli G* satisfying at least one of the following conditions (i) to (v), G′ 0.5% and G′ 20% being measured according to the standard ISO 4664 at respective dynamic strain amplitudes of 0.5% and 20%, on double shear test specimens subjected to shear strains of from 0.02% to 50% at the same frequency of 5 Hz and at the same temperature T:G′0.5%/G′20%≤1.15 for T=100° C., (i)G′0.5%/G′20%≤1.40 for T=65° C., (ii)G′0.5%/G′20%≤1.50 for T=25° C., (iii)G′0.5%/G′20%≤1.60 for T=0° C., (iv)G′0.5%/G′20%≤2.50 for T=−30° C. (v)