In-Chain Functionalized Elastomer Filler Affinity
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Solution Overview
Problem
Existing functionalized polymers used in tire tread compositions exhibit inconsistent viscoelastic properties, requiring blends of synthetic and natural rubber to achieve desired rolling resistance and wet skid resistance, and there is a need to improve the affinity of fillers like carbon black and silica for rubber polymers to enhance tire performance.
Innovation Solution
A functionalized elastomer copolymer is synthesized using monofunctional organolithium initiators, specifically organolithium compounds like n-butyllithium, to create a block copolymer with improved in-chain functionalization, which is then compounded with fillers such as silica and carbon black to enhance their dispersion and affinity, thereby improving tire performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blends of synthetic and natural rubber are used to achieve desired rolling resistance and wet skid resistance, then tire performance properties are improved, but the device complexity and manufacturing process complexity increase
Solution Approach 1:
The patent extracts and addresses the specific problem of filler-rubber affinity by introducing functional groups (carboxyl, hydroxyl, amine) directly onto the polymer chains. This extraction of the affinity problem allows for a targeted solution through chemical modification rather than complex blending, resolving the contradiction by simplifying the composition while maintaining performance.
Solution Approach 2:
The patent changes the chemical parameters of the rubber polymer by introducing functional groups at controlled concentrations (0.1-10 mmol/kg). This parameter change directly improves filler affinity and tire performance without requiring complex blends, thereby resolving the contradiction between performance and composition simplicity.
2Reliability
If conventional polymerization methods are used, then production is simpler, but the filler affinity and dispersion of rubber polymers are insufficient
Solution Approach 1:
The patent applies preliminary action by introducing functional groups during the polymerization process itself, rather than attempting to improve filler affinity after polymer formation. This preliminary chemical modification ensures that the polymer chains are pre-equipped with affinity groups, simplifying subsequent compounding while achieving superior filler interaction.
Solution Approach 2:
The functional groups (carboxyl, hydroxyl, amine) act as intermediaries between the rubber polymer and the filler particles. These intermediary groups facilitate better interaction and dispersion between the polymer matrix and fillers like carbon black and silica, resolving the affinity problem without complicating the overall manufacturing process.
3Reliability
If in-chain functionalization is implemented, then filler dispersion and affinity are improved, but the manufacturing precision and process control difficulty increase
Solution Approach 1:
The patent carefully controls the concentration parameter of functional groups within a specific range (0.1-10 mmol/kg) to optimize filler dispersion while maintaining manufacturability. This parameter optimization resolves the contradiction by finding the sweet spot where sufficient affinity is achieved without excessive process complexity.
Solution Approach 2:
The patent introduces functional groups at specific local positions along the polymer chains (in-chain functionalization) rather than uniform distribution. This local quality approach allows for targeted improvement of filler interaction zones while maintaining the overall simplicity of the polymerization process and controlling functional group concentration within manageable limits.
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 synthesis of the functionalized elastomer with improved filler affinity leads to enhanced rolling resistance and traction characteristics of tires, addressing the inconsistency in viscoelastic properties and improving tire performance.
Implementation Method 1
In the living polymerization process based on active carbanionic center, metals from Groups I and II of the periodic table are commonly used to initiate the polymerization of monomers into polymers
Implementation Method 2
the physical properties of such cured rubbers depend upon the degree to which the filler is homogeneously dispersed throughout the rubber. This is in turn related to the level of affinity that filler has for the particular rubbery polymer
Implementation Method 3
the functionalized elastomer is a copolymer of a first monomer and a second monomer... the functionalized elastomer comprises in-chain functionalization
Data Source
AI summary
A functionalized elastomer and its method of manufacturing is disclosed. The functionalized elastomer is a copolymer of a first monomer and a second monomer, the first monomer being selected from the group consisting of a conjugated diene monomer and a vinyl aromatic monomer, and the second monomer being of formula 1 wherein R1 is selected from a C1 to a C8 alkyl, aryl or substituted aryl group or is -SiR3 where R3 are independently selected from a C1 to a C8 alkyl group; wherein R2 is selected from a C1 to a C8 alkyl, aryl or substituted aryl group or is -SiR3; and wherein n = 0 to 3. Also, a rubber composition and a pneumatic tire comprising such a functionalized elastomer is disclosed.