Functionalized Polydienes for Low Hysteresis and Cold Flow
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Solution Overview
Problem
Current functionalized polymers used in tire manufacturing exhibit high cold flow due to their linear backbone structure, which complicates storage and processing, and their effectiveness in reducing hysteresis is unpredictable, making it challenging to develop polymers with both low hysteresis and reduced cold flow.
Innovation Solution
The method involves polymerizing conjugated diene monomers using a lanthanide-based catalyst system to form reactive polymers, which are then functionalized with protected polyoxime compounds, resulting in polymers with improved cold-flow resistance and reduced hysteresis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cis-1,4-polydienes are prepared with lanthanide-based catalysts to achieve better tensile properties, higher abrasion resistance, lower hysteresis, and better fatigue resistance, then the polymers exhibit high cold flow which causes problems during storage and transport and hinders the use of automatic feeding equipment
Solution Approach 1:
The patent changes the chemical parameter of the polymer by introducing functional groups (such as hydroxyl, carboxyl, or amine groups) at the chain ends through post-polymerization treatment with functionalizing agents. This chemical modification alters the intermolecular interactions, reducing cold flow while preserving the mechanical properties provided by the cis-1,4-linkage structure.
Solution Approach 2:
The patent creates a composite structure by combining the cis-1,4-polydiene backbone with functional groups attached at the chain ends. This composite approach maintains the advantageous mechanical properties of the linear cis-1,4 structure while adding the functional groups necessary to reduce cold flow and improve processing characteristics.
2Loss of energy
If functionalized polymers are employed to reduce the hysteresis of rubber vulcanizates, then the functional group may reduce the number of free polymer chain ends via interaction with filler particles, but whether a particular functional group can reduce hysteresis is often unpredictable
Solution Approach 1:
The patent systematically varies the functional group parameter (testing different groups such as hydroxyl, carboxyl, amine) to identify which specific functional groups most effectively reduce hysteresis. By changing this chemical parameter and measuring the resulting hysteresis, the patent establishes structure-property relationships that improve predictability.
Solution Approach 2:
The patent employs a feedback approach by measuring the hysteresis properties of vulcanizates prepared from polymers with different functional groups, then using this information to select the optimal functional group for minimizing energy loss. This iterative process of modification, measurement, and selection builds a knowledge base for predictable functional group performance.
3Ease of manufacture
If functionalized polymers are prepared by post-polymerization treatment of reactive polymers with certain functionalizing agents, then the polymer chains possess reactive ends that can react with functionalizing agents, but whether a reactive polymer can be functionalized by treatment with a particular functionalizing agent can be unpredictable
Solution Approach 1:
The patent identifies functionalizing agents with universal reactivity toward the reactive chain ends produced by lanthanide-based catalysts. By selecting functionalizing agents that can reliably react with the specific reactive ends (such as metal alkyls or carbanions), the patent creates a multi-functional approach that works across different polymer systems, improving predictability of functionalization success.
Solution Approach 2:
The patent modifies the reaction parameter by optimizing the choice of functionalizing agent to match the specific reactive ends present in the polymer. By changing the chemical nature of the functionalizing agent to complement the reactive polymer ends, the patent ensures reliable and predictable functionalization while maintaining ease of manufacture.
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 polymers demonstrate enhanced cold-flow resistance and low hysteresis, making them suitable for tire components with improved mechanical properties and processing ease.
Implementation Method 1
Lanthanide-based catalyst systems are known to be useful for polymerizing conjugated diene monomers to form polydienes having a high content of cis-1,4 linkage
Implementation Method 2
reacting the reactive polymer with a protected polyoxime compound
Data Source
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AI summary
A method for preparing a functionalized polymer, the method comprising the steps of polymerizing monomer to form a reactive polymer, and reacting the reactive polymer with a protected polyoxime compound.