Cyclic Carbonate Monomers for Cationic Polycarbonates
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Solution Overview
Problem
Current ring opening polymerizations of cyclic carbonates are limited by the lack of main chain functionality and instability of monomers incorporating heteroatoms, such as nitrogen, within the polymer backbone, which hampers the incorporation of heteroatoms other than carbonate oxygens.
Innovation Solution
The development of cyclic carbonate monomers with a tertiary amine nitrogen in the cyclic carbonate ring, allowing for organocatalyzed ring opening polymerization to form cationic polycarbonates with a quaternary nitrogen, which can react with quaternizing agents to form antimicrobial cationic polymers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If heteroatoms (e.g., nitrogen) are incorporated in the polymer backbone, then main chain functionality is improved, but monomer instability worsens
Solution Approach 1:
The patent divides the monomer structure into stable cyclic carbonate ring segments and functional heteroatom segments. The cyclic carbonate ring provides structural stability while the incorporated nitrogen heteroatom provides main chain functionality. This segmentation allows the monomer to maintain stability during storage and handling while enabling the desired functional properties in the final polymer.
Solution Approach 2:
The patent uses cyclic carbonate ring structures as intermediary compounds that bridge the gap between stable monomers and functional polymers. The cyclic carbonate serves as a stable precursor that can be polymerized under controlled conditions to form the final polymer with heteroatom functionality in the backbone, thus acting as an intermediary that resolves the stability-functionality contradiction.
2Adaptability or versatility
If cyclic carbonate monomers with ring nitrogen are developed, then heteroatom incorporation is improved, but monomer availability worsens
Solution Approach 1:
The patent performs preliminary synthesis of cyclic carbonate monomers with incorporated nitrogen heteroatoms before the polymerization step. By preparing these specialized monomers in advance through controlled chemical reactions between diols and phosgene or its equivalents, the invention ensures that the required functional monomers are available when needed, resolving the availability issue while maintaining heteroatom incorporation capability.
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 resulting cationic polymers exhibit potent antimicrobial activity against various microbes, including Gram-negative, Gram-positive, yeast, and fungi, while maintaining biodegradability and low cytotoxicity.
Implementation Method 1
forming an initial polymer by ring opening polymerization of the compound, the initial polymer comprising a basic repeat unit comprising a backbone carbonate group and a backbone tertiary nitrogen
Implementation Method 2
organocatalyzed ring opening polymerization
Implementation Method 3
treating the initial polymer with the quaternizing agent, thereby forming a cationic polymer comprising a cationic repeat unit comprising the backbone carbonate group and the positive-charged backbone quaternary nitrogen
Data Source
AI summary
Eight-membered ring cyclic carbonates having an oxygen or an acylated nitrogen at position 6 were prepared by reaction of precursor diols with ethyl chloroformate. The cyclic carbonates undergo organocatalyzed ring opening polymerization. In one instance, the initial polymer formed comprises a carbonate repeat unit having a Boc-protected nitrogen in the polymer backbone. Deprotecting the nitrogen with acid forms a cationic carbonate repeat unit having a positive charged secondary ammonium nitrogen in the polymer backbone.