Crosslinkable Prepolymers With Hydrophobic Linkers for Stable Hydrogels
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Solution Overview
Problem
Existing hydrogels based on PEG-DMA or PEG-DAAm degrade rapidly under physiological conditions due to hydrolytic instability and oxidative degradation, limiting their long-term stability and effectiveness in biomedical applications.
Innovation Solution
Development of water-soluble crosslinkable prepolymers with hydrophobic linkers and suitable antioxidants, which form chemically stable crosslinked polymer gels resistant to hydrolytic and oxidative degradation, using prepolymers with specific backbones and endgroups, and incorporating phenolic or aminoxyl radical stabilizers during the polymerization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If water-soluble prepolymers are used to form hydrogels, then water-based processing and biocompatibility are improved, but hydrolytic stability and long-term chemical stability deteriorate
Solution Approach 1:
The patent uses composite prepolymers combining PEG backbone with hydrophobic linker moieties (such as polyols with long carbon chains) to create a material that maintains water solubility while introducing hydrophobic segments that resist hydrolysis. This composite structure allows the gel to benefit from both aqueous compatibility and enhanced chemical stability.
Solution Approach 2:
The patent introduces hydrophobic linkers at specific positions within the polymer chain (between crosslinkable end groups), creating localized hydrophobic regions that provide stability against hydrolysis while the overall polymer remains water-soluble due to the hydrophilic PEG backbone and crosslinkable end groups.
2Reliability
If phenolic antioxidants are added to suppress oxidative degradation, then oxidative stability is improved, but free-radical polymerization is inhibited
Solution Approach 1:
The patent incorporates antioxidants into the prepolymer structure before polymerization occurs, allowing the material to be pre-protected against oxidative degradation during storage and handling, while the actual polymerization is then initiated separately under controlled conditions.
Solution Approach 2:
The patent uses alternative antioxidant systems that do not interfere with free-radical polymerization, such as metal-based antioxidants or antioxidants that are activated only after polymerization is complete, thereby maintaining both protective function and polymerization efficiency.
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 crosslinked polymer gels maintain at least 95% of their initial dry mass after 8 weeks in water and exhibit long-term stability, suitable for medical and dental applications.
Implementation Method 1
They can be obtained by chemical crosslinking of a solution of water soluble prepolymers bearing crosslinkable groups
Implementation Method 2
The hydrolytic degradation of the polyester moieties renders the gel degradable
Implementation Method 3
presumably by oxidation of the terminal OH-groups and/or the internal ether moieties
Data Source
AI summary
The invention relates to water soluble crosslinkable prepolymers for the preparation of chemically stable crosslinked polymer gels, a process for preparing the same, compositions containing the same and their use such as a medical or dental filler composition.