Triethylamine Functionalized Elastomer Clay Dispersion
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Solution Overview
Problem
The tire industry faces challenges in achieving good clay dispersion and exfoliation in elastomer nanocomposites due to incompatibility between hydrophobic isobutylene elastomers and hydrophilic inorganic clays, leading to increased viscosity when ammonium functionality is incorporated, which complicates processing and barrier property enhancement.
Innovation Solution
Partial triethylamine functionalization of halogenated elastomers, such as BIMS polymers, promotes clay dispersion and improves barrier properties while controlling Mooney viscosity through adjustable functionality levels, preventing severe viscosity increases and maintaining processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ammonium functionality is incorporated into the polymer to improve clay dispersion and barrier properties, then clay dispersion and exfoliation are improved, but the viscosity of the polymer increases significantly due to ionomeric associations
Solution Approach 1:
The patent changes the chemical structure parameter of the ammonium functionality by introducing long chain alkyl substituents (C12-C20) on the nitrogen atom. This parameter change reduces the strength of ionomeric associations between ammonium groups, thereby decreasing polymer viscosity while maintaining the ability to interact with clay surfaces for improved dispersion and barrier properties.
Solution Approach 2:
The long chain alkyl groups act as intermediary structures that mediate between the polar ammonium functionality and the hydrophobic polymer matrix. These alkyl chains reduce the polarity and ionomeric character of the ammonium groups, allowing better compatibility with the hydrocarbon-based elastomer while still enabling clay interaction through the ammonium head groups.
2Reliability
If hydrophilic inorganic clays are used in elastomer nanocomposites to improve barrier properties, then barrier property is improved, but clay dispersion and exfoliation are poor due to incompatibility between hydrophobic elastomer and hydrophilic clay
Solution Approach 1:
The patent modifies the surface chemistry parameter of the clay by incorporating ammonium functionality with long chain alkyl groups. This changes the clay surface from hydrophilic to amphiphilic or hydrophobic character, improving compatibility with the hydrophobic elastomer matrix and enabling better dispersion and exfoliation while maintaining barrier properties.
Solution Approach 2:
The patent creates a composite functional group on the polymer chain that combines the polar ammonium moiety (for clay interaction) with non-polar long chain alkyl groups (for elastomer compatibility). This composite structure enables simultaneous affinity for both hydrophobic elastomer and hydrophilic clay surfaces, achieving stable nanocomposite formation with improved barrier 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
Triethylamine-functionalized BIMS polymers achieve enhanced barrier properties and controllable processability, allowing for effective clay dispersion and exfoliation, thereby improving the performance of elastomer nanocomposites in air barrier applications.
Implementation Method 1
Organoclays are typically produced through ion-exchange reactions that replace sodium ions that exist on the surface of sodium montmorillonite with organic molecules
Implementation Method 2
Functionalization of the BIMS polymers for use in nanocomposites has also been shown to provide a better interaction between the functionality on the polymer and clay surface
Implementation Method 3
Ideally, intercalation should take place in the nanocomposite, wherein the polymer inserts into the space or gallery between the clay surfaces
Data Source
AI summary
A halogenated elastomer partially functionalized with triethylamine, in a mixture with fiiier and a cure package, suitable for use as an air barrier in an innertube or tire innerliner, is disclosed. The halogenated elastomer can be a polymer comprising C4 to C7 isoolefm derived units, para-alkylstyrene derived units, para-(haloalkylstyrene) derived units, and para-(triethylammoniumalkylstyrene) derived units. The Mooney viscosity of the elastomer can be controlled by the degree of triethylamine functionalization. Also disclosed is a method for making an article using the tri ethy iamine-functionalized elastomer.