Grafted Rubber Composition for Tire Rolling Resistance
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Solution Overview
Problem
Tire materials face a challenge in balancing rolling resistance and strain acceptance, as increasing covalent crosslinks improve stiffness but decrease elongation at break, while decreasing crosslinks enhance elongation but reduce stiffness, making it difficult to achieve both low rolling resistance and high strain acceptance without damage.
Innovation Solution
Incorporating a specific density of noncovalent bonds between polymer chains through the use of modifying agents that form associative groups, which are grafted onto the elastomer chains, allowing for both chemical and physical crosslinking to achieve the desired balance of stiffness and elongation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the number of covalent bonds between polymer chains (bridge density) is increased, then stiffness at low and moderate strains increases, but elongation at break decreases
Solution Approach 1:
The patent creates a composite crosslinking system combining two types of bonds: covalent crosslinks (from chemical crosslinking agents like sulphur or peroxides) and noncovalent physical crosslinks (from associative groups in modifying agents). This composite structure allows the material to exhibit both high stiffness at low strains (from covalent bonds) and high elongation at break (from reversible physical bonds), resolving the contradiction between these two properties.
Solution Approach 2:
The patent changes the chemical structure of the elastomer by grafting modifying agents with associative groups (capable of forming noncovalent bonds). This parameter change in the polymer architecture enables the formation of physical crosslinks in addition to chemical crosslinks, allowing simultaneous optimization of both stiffness and elongation properties that were previously mutually exclusive.
2Ease of operation
If the bridge density of covalent bonds decreases, then elongation at break increases, but stiffness at low and moderate strains decreases
Solution Approach 1:
The patent creates a composite crosslinking system combining two types of bonds: covalent crosslinks (from chemical crosslinking agents like sulphur or peroxides) and noncovalent physical crosslinks (from associative groups in modifying agents). This composite structure allows the material to exhibit both high stiffness at low strains (from covalent bonds) and high elongation at break (from reversible physical bonds), resolving the contradiction between these two properties.
Solution Approach 2:
The patent changes the chemical structure of the elastomer by grafting modifying agents with associative groups (capable of forming noncovalent bonds). This parameter change in the polymer architecture enables the formation of physical crosslinks in addition to chemical crosslinks, allowing simultaneous optimization of both stiffness and elongation properties that were previously mutually exclusive.
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 solution enables tires to maintain stiffness at low and moderate strains while achieving high elongation at break, improving rolling resistance and strain acceptance without damage, as demonstrated by enhanced mechanical properties and reduced hysteresis.
Implementation Method 1
Physical crosslinking can be obtained by functionalising the chain of the polymer with chemical molecules capable of associating with one another via nonpermanent physical interactions, such as ionic interactions, hydrogen bonds, ion-dipole interactions and dipole-dipole interactions.
Implementation Method 2
Physical crosslinking can be obtained by functionalising the chain of the polymer with chemical molecules capable of associating with one another via nonpermanent physical interactions, such as ionic interactions, hydrogen bonds, ion-dipole interactions and dipole-dipole interactions.
Implementation Method 3
Physical crosslinking can be obtained by functionalising the chain of the polymer with chemical molecules capable of associating with one another via nonpermanent physical interactions, such as ionic interactions, hydrogen bonds, ion-dipole interactions and dipole-dipole interactions.
Implementation Method 4
Chemical crosslinking is characterized by the establishment of covalent chemical bonds between the polymer chains.
Data Source
AI summary
The invention relates to a tire comprising at least one rubber composition based on at least one diene elastomer, one reinforcing filler, one chemical crosslinking agent and one modifying agent, chosen from the compounds of following formula (I):whereR denotes a unit comprising at least one reactive group,R1 denotes hydrogen,R2 denotes an alkylene radical comprising from 2 to 8 carbon atoms and optionally one or more heteroatoms chosen from S, N, O or Si,A denotes an oxygen or sulphur atom or an ═NH group, preferably an oxygen atom.