Self-Crosslinked Poly(ether Imide)s for Solvent-Resistant Films
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Solution Overview
Problem
Poly(ether imide) (PEI) polymers face challenges in achieving desirable thermal properties, mechanical properties, and solvent resistance, particularly due to low solvent resistance in common solvents like THF, DCM, chloroform, DMF, and NMP, and existing crosslinking methods are inefficient, costly, or pose explosion risks.
Innovation Solution
Synthesis of azide-containing PEIs via a heterogenous diazotizationazidation reaction, followed by thermal crosslinking, resulting in crosslinked PEIs (X-PEIs) with high crosslinking density and improved solvent resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PEI is solution-processed in common solvents, then processability is improved, but solvent resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by introducing crosslinking density as a new parameter to transform the polymer structure from linear to crosslinked network. This structural parameter change enables the polymer to maintain processability through solution casting while achieving solvent resistance through the formed crosslinked network structure.
Solution Approach 2:
The patent creates a composite structure at the molecular level by forming crosslinked bonds between polymer chains. The crosslinked PEI network combines the processability of solution-cast PEI with the solvent resistance of crosslinked structures, effectively creating a composite material system with dual properties.
2Productivity
If UV crosslinking is used, then crosslinking efficiency is improved, but polymer backbone degradation worsens
Solution Approach 1:
The patent substitutes the UV irradiation mechanism with a thermal mechanism. Instead of using UV light to initiate crosslinking, the patent employs thermal energy to activate the azide groups for crosslinking. This substitution eliminates the harmful UV effect on the polymer backbone while maintaining crosslinking functionality.
Solution Approach 2:
The patent introduces azide groups as intermediary functional groups that mediate the crosslinking process. These azide groups serve as intermediaries that can be activated thermally to form crosslinks without requiring UV irradiation, thus protecting the polymer backbone from degradation while enabling efficient crosslinking.
3Stability of the object's composition
If thermal crosslinking with typical crosslinkers is used, then uniformity is improved, but process complexity and cost worsen
Solution Approach 1:
The patent extracts and eliminates the need for external crosslinking agents from the system. By incorporating azide groups directly into the PEI polymer chains during synthesis, the patent removes the requirement for separate crosslinker additives, simplifying the overall process while maintaining uniform crosslinking throughout the material.
Solution Approach 2:
The patent merges the crosslinking functionality with the polymer structure itself by incorporating azide groups into the PEI chains. This merging eliminates the need for separate crosslinking agents and simplifies the process, as the polymer contains its own crosslinking capability intrinsic to its structure.
4Reliability
If azide-based small molecules are used for crosslinking, then crosslinking effectiveness is improved, but explosion risk worsens
Solution Approach 1:
The patent segments the azide functionality from small molecular compounds and incorporates it into the polymer chain structure. By distributing azide groups along the polymer backbone rather than using small molecular azides, the patent maintains crosslinking effectiveness while eliminating the explosion risks associated with concentrated small molecular azides.
Solution Approach 2:
The patent creates a polymer-based crosslinking system that copies the functional benefits of small molecular azide crosslinkers without replicating their harmful properties. The azide groups incorporated into the polymer chains provide the same crosslinking functionality while avoiding the explosion risks of small molecular azide compounds.
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
X-PEIs exhibit superior thermal and mechanical properties, with outstanding resistance to classical solvents, avoiding explosion risks and linker leaching, and maintaining structural integrity under elevated temperatures.
Implementation Method 1
Thermolysis of azides at moderate temperatures (
Data Source
AI summary
In one aspect, the disclosure relates to azide-containing poly(ether imide) polymers (PEIs; N3-PEI-N3) synthesized via a heterogenous diazotizationazidation reaction. In one aspect, the azide-containing PEIs can be solution-cast into films and then thermally crosslinked. In a further aspect, the crosslinked PEIs (X-PEIs) exhibit superior thermal and mechanical properties. In a still further aspect, X-PEIs display outstanding resistance to classical solvents for conventional PEI, including THF, DCM, chloroform, DMF, and NMP. In another aspect, with an initial number average molecular weight (Mn) of 8.9 kDa, the disclosed azide-containing PEIs have a high crosslinking density and thus possess desirable thermal, mechanical, and solvent resistance properties.