Bifunctional Silane Photoinitiator for UV Polymerization
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Solution Overview
Problem
Conventional bifunctional silanes are not compatible with moderate polymerization temperatures or applications requiring the absence of sulfur, such as photopolymerization, limiting their use in hybrid polymer/filler materials with improved mechanical and chemical properties.
Innovation Solution
Development of a novel bifunctional silane compound that can function as a photoinitiator for photopolymerization at ambient temperature without an external initiator, offering effective coupling between polymers and fillers, and being non-selective with respect to monomers, thus enabling the creation of hybrid polymer/filler materials with enhanced mechanical and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional bifunctional silanes are used for coupling silica particles with polymers, then chemical bonding between filler and polymer is achieved, but the system is not compatible with photopolymerization processes requiring moderate temperatures and absence of sulfur
Solution Approach 1:
The patent changes the chemical parameters of the silane coupling agent by replacing the sulfur-based vulcanization mechanism with a photoinitiator system that operates at ambient temperature under UV irradiation. This parameter change enables compatibility with photopolymerization while maintaining the coupling function between silica and polymer matrix
Solution Approach 2:
The patent creates a universal coupling system that can work with multiple polymer types (vinyl, epoxy, polyester) and multiple silica particle sizes through a single photoinitiator-based mechanism, eliminating the need for different silane formulations for different application scenarios
2Strength
If high temperature vulcanization is used to achieve polymer-filler coupling, then strong chemical bonds are formed, but the process generates heat that degrades lubricant coatings on medical devices
Solution Approach 1:
The patent replaces the thermal-vulcanization mechanism with a photochemical polymerization system initiated by UV light. This substitution eliminates the need for high temperature heating, thereby preventing degradation of heat-sensitive lubricant coatings on medical device components while maintaining strong polymer-filler bonding
Solution Approach 2:
The patent utilizes the phase transition from liquid monomer to solid polymer through photopolymerization at ambient temperature. This phase change occurs without external heating, avoiding thermal damage to surrounding components while achieving the desired crosslinked network structure for strong bonding
3Reliability
If commercial silane structures are used for high temperature processing, then effective coupling is achieved, but the structures are incompatible with moderate temperature photopolymerization systems
Solution Approach 1:
The patent modifies the operational temperature parameter from high temperature (170°C vulcanization) to ambient temperature photopolymerization. This is achieved by incorporating a photoinitiator group into the silane structure, which enables the coupling reaction to proceed under UV irradiation at room temperature, expanding the applicable temperature range
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 novel bifunctional silane compound provides improved mechanical hardness and chemical bonding between polymers and fillers, offering stability and non-selectivity in monomer compatibility, enhancing the properties of hybrid materials in various applications including medical and mechanical fields.
Implementation Method 1
The photopolymerization process consists in converting the liquid monomer into an insoluble polymer at room temperature under light irradiation. The light emitted is often located in the ultraviolet (or visible) region of the electromagnetic spectrum, which reacts with light-sensitive compounds, called 'photoinitiators', so as to create free radicals at room temperature.
Implementation Method 2
it is not possible to use them directly as a filler in their raw state. This problem is solved by the use of bifunctional silanes as coupling agents, so as to modify the hydrophilic nature of the silica particles and to ensure a chemical bond between these nanoparticles and the polymers
Data Source
AI summary
The present invention relates to a compound of formula (I) below:in which:R1 represents, in particular, an alkylene group comprising from 1 to 6 carbon atoms;R2 and R3 are, in particular, H;n is 0, 1, 2 or 3; and R4 is chosen from the group consisting of: NO2, ORa, SRa and NRaRb, wherein Ra and Rb are as defined above;R5 and R6, identical or different, represent an alkyl or alkoxy group comprising from 1 to 6 carbon atoms; andR7, R8 and R9, identical or different, represent an alkyl group comprising from 2 to 6 carbon atoms.