Functionalized Elastomer Synthesis via Neodymium Catalyst
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Solution Overview
Problem
Current methods for producing stereoregular polymers functionalized with polar groups are challenging due to catalyst sensitivity towards heteroatom-containing substrates, particularly in stereoselective diene polymerization, which limits the incorporation of polar groups into the polymer backbone and end-groups, affecting compatibility with polar surfaces and cross-linking.
Innovation Solution
The use of polar functionalized organo-metal activators in combination with neodymium-based catalyst systems, specifically Nd(BH4)3.(THF)3 activated with magnesium alkyls, allows for the synthesis of stereoregular, trifunctional, hetero-telechelic poly(dienes) with functional groups in the polymer backbone and at both chain ends, enabling compatibility with various functional activators and monomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional catalysts are used for stereoselective diene polymerization, then stereoregularity is achieved, but the catalyst sensitivity towards heteroatom-containing substrates prevents incorporation of polar groups into the polymer backbone and end-groups
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using neodymium borohydride Nd(BH4)3 instead of conventional sensitive catalysts, and activates it with functionalized magnesium alkyls. This parameter change allows the catalyst to tolerate heteroatom-containing substrates while maintaining stereoselectivity, enabling incorporation of polar groups into both the polymer backbone and end-groups.
Solution Approach 2:
The patent introduces functionalized magnesium alkyls as intermediary compounds that mediate between the neodymium borohydride catalyst and the heteroatom-containing monomers. These intermediaries facilitate the transfer of polar functional groups to the polymer chains without deactivating the catalyst, thus resolving the sensitivity issue.
2Adaptability or versatility
If functionalized organo-metal activators are used to introduce polar groups, then compatibility with polar surfaces is enhanced, but the complexity of the catalyst system increases
Solution Approach 1:
The neodymium borohydride catalyst system activated with functionalized magnesium alkyls serves multiple functions simultaneously: it maintains stereoselectivity for cis-1,4-polybutadiene formation, activates the polymerization of heteroatom-containing monomers, and transfers polar functional groups to both backbone and end-groups. This multi-functionality reduces the need for separate processing steps.
3Strength
If stereoregular poly(dienes) with functional groups are synthesized, then cross-linking capabilities are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by introducing polar functional groups at specific locations - both in the polymer backbone through copolymerization with heteroatom-containing monomers and at the chain end-groups through the activation process. This localized functionalization enhances cross-linking capabilities at critical positions while maintaining overall stereoregularity.
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
This approach enables the simultaneous introduction of functional groups into the polymer backbone and chain ends, resulting in stereoregular polymers with high cis or trans configurations, enhancing compatibility and cross-linking capabilities, and allowing for the production of functionalized elastomers with improved properties.
Implementation Method 1
Nd(BH4)3.(THF)3 catalyzes, after activation with MgR2, the direct copolymerization of 1,3-butadiene or isoprene with polar functionalized dienes
Implementation Method 2
Stereoregular poly(dienes) with three different functional groups were synthesized by insertion polymerization
Data Source
AI summary
The present invention is directed to a stereoregular functionalized elastomer represented by poly(M1 co M2), wherein the functionalized elastomer comprises a microstructure selected from the group consisting of microstructures having at least 90 percent by weight of monomer residues in trans 1,4-configuration, and microstructures having at least 80 percent by weight of monomer residues in cis 1,4-configuration; wherein M1 is selected from the group consisting of isoprene and 1,3-butadiene; and M2 is of formula 4wherein R6 is a covalent bond, phenylene, a linear or branched alkane diyl group containing 1 to 10 carbon atoms, or a combination of one or more phenylene groups and one or more linear or branched alkane diyl groups containing 1 to 10 carbon atoms; R7 is hydrogen or a linear or branched alkyl group containing 1 to 10 carbon atoms; X1 is selected from formulas 5 and 6wherein R8 and R9 are independently trialkylsilyl, phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or one of R8 and R9 is hydrogen and the other is phenyl or a linear or branched alkyl group containing 1 to 10 carbon atoms, or R8 and R9 taken together with the nitrogen atom represent a nitrogen containing heterocyclic group containing from 4 to 12 carbon atoms; and X2 is a sulfur atom or a structure of formula 7 or 8wherein when X2 is of formula 8, the S atom of formula 8 is adjacent to the phenyl ring of formula 6 and the N atom of formula 8 is adjacent to R6.