Symmetrical Hyperbranched Silicone Polymer Synthesis
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Solution Overview
Problem
Conventional methods face challenges in synthesizing highly branched silicone compounds with good purity and reactivity due to internal rearrangement issues during hydrosilylation reactions, leading to poor flexibility and positional symmetry, which affects their applicability in pharmaceuticals, medical devices, and foods.
Innovation Solution
A symmetric hyperbranched type silicone-modified polymerizable compound is developed, incorporating a siloxane chain with an oligoglycerin ether group and a divalent hydrocarbonylene methylene ether group, along with a modularized preparation method using a hydrosilylation reaction with a transition metal catalyst to suppress internal rearrangement products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the convergent method is used to prepare highly branched silicone compounds, then purification is easier and high purity can be obtained, but reactivity is lowered due to steric hindrance at the apex of bulky side chains
Solution Approach 1:
The invention uses a divergent method that segments the branching process into sequential generations (first generation with 1 siloxane chain, second generation with 2 chains, third generation with 3 chains per side chain). This segmentation allows each branch to extend outward from the core without creating bulky apex structures, maintaining reactivity while achieving high branching degree and purity.
2Reliability
If the divergent method is used to prepare highly branched silicone compounds, then reactivity is maintained due to outward extension of branches, but separation of compounds with different distributions is difficult and purity is reduced
Solution Approach 1:
The invention carefully controls the molar ratios of reactants at each stage of the divergent synthesis. By using specific molar ratios (e.g., controlling the amount of H-siloxane relative to the polyol core and intermediate products), the invention achieves uniform branching distributions across generations, making separation easier and purity higher while maintaining the reactivity benefits of the divergent method.
3Ease of manufacture
If siloxane chains are introduced into allyl ether compounds by hydrosilylation, then a branched silicone structure is formed, but 10 to 20% of olefins undergo internal rearrangement to form 1-propenyl ether products that generate bad odor upon hydrolysis
Solution Approach 1:
The invention converts the harmful internal rearrangement reaction into a beneficial outcome by using the resulting 1-propenyl ether structures as part of the final product architecture. The patent specifically designs the polymerizable compound to incorporate these rearranged structures, transforming what was previously a defect (bad odor upon hydrolysis) into an accepted structural feature of the silicone-modified polymerizable compound, thereby eliminating the odor problem while maintaining the branched silicone structure.
4Reliability
If conventional siloxane dendrimers are grafted to polymerizable compounds, then mold releasing and lubricant properties are improved, but the narrow branched chain and chemical structural rigidity reduce flexibility and steric hindrance increases with generation
Solution Approach 1:
The invention creates a composite structure by combining flexible oligoglycerin ether backbones with siloxane side chains. This composite approach integrates the flexibility of the glycerin-based core with the functional benefits of siloxane groups, achieving both mold releasing properties and reduced steric hindrance. The modular design allows the polymerizable functional groups to remain accessible while maintaining the desired silicone 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
The approach results in a material with enhanced flexibility and reactivity of the polymerizable functional group, achieving a highly branched structure with improved purity and reduced internal rearrangement, suitable for various applications.
Implementation Method 1
a modularized preparation method which comprises preparing the compound represented by general formula (1) by subjecting a compound represented by general formula (2) and an intermediate represented by general formula (3) to a hydrosilylation reaction
Implementation Method 2
a modularized preparation method using a hydrosilylation reaction with a transition metal catalyst to suppress internal rearrangement products
Data Source
AI summary
The present invention relates to a symmetric hyperbranched type silicone-modified polymerizable compound containing a compound represented by the following general formula (1). There can be provided a hyperbranched type silicone-modified polymerizable compound which has flexibility at the branched skeleton itself than the conventional ones, as well as reactivity of a polymerizable functional group is good and it is positionally and sterically symmetric, while it has a highly branched structure having siloxane chains. [(RARB)2CHOCH2]2CHORCcRD (1) wherein RA represents a monovalent linear, branched or cyclic siloxane chain; RB represents a divalent hydrocarbonylene methylene ether group represented by -CH2CRb1Rb2(CRb3Rb4)n1OCH2-, each of Rb1, Rb2, Rb3 and Rb4 may be the same or different from each other and represents a hydrogen atom or a linear, branched or cyclic hydrocarbon group having 1 to 10 carbon atoms which may be bonded to each other, "n1" represents an integer selected from 0 to 10; RC represents a divalent linking group; "c" represents 0 or 1; and RD represents an unsaturated polymerizable functional group.