Crosslink Density Measurement in Sulfur Polymer Composites
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Solution Overview
Problem
Conventional methods for analyzing sulfur crosslinked structures in sulfur-containing polymer composite materials, such as rubber vulcanizates, are insufficient as they cannot accurately determine the crosslink densities of polysulfide bonds with 2 to 8 sulfur atoms, and the reagent used to cleave polysulfide bonds has a strong odor, limiting the detail and accuracy of property control.
Innovation Solution
A method involving high-intensity monochromatic X-ray irradiation to measure X-ray absorption spectra, followed by a reverse Monte Carlo analysis to determine the three-dimensional structure of sulfur atoms, allowing for the calculation of crosslink densities for sulfide bonds with 1 to 8 sulfur atoms, providing detailed information on the sulfur crosslinked structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reagent-based methods (LiAlH4 or propane-2-thiol) are used to cleave crosslinks and calculate crosslink densities, then the measurement process is simple, but the details of polysulfide bonds (n=2 to 8) cannot be revealed and measurement precision is insufficient
Solution Approach 1:
The patent replaces the chemical reagent-based cleavage method with an X-ray based physical measurement method. Specifically, X-ray absorption spectroscopy is used to directly probe the sulfur crosslink structure without chemical cleavage, allowing differentiation of polysulfide bonds with n=2 to 8 sulfur atoms based on their distinct absorption spectra. This substitution enables precise measurement of individual polysulfide bond types while avoiding the limitations of reagent-based methods.
Solution Approach 2:
The patent utilizes changes in X-ray absorption parameters (absorption coefficient, edge position, fine structure) as a function of sulfur atom number in polysulfide bonds. By measuring X-ray absorption spectra at different energies and analyzing the characteristic absorption edges and fine structures, the method can distinguish and quantify different polysulfide bond types (n=1 to 8) based on their unique spectral fingerprints, thereby achieving detailed crosslink structure analysis.
2Measurement precision
If propane-2-thiol is used to preferentially cleave polysulfide bonds, then polysulfide bond analysis is enabled, but the strong odor makes it unusable in practical applications
Solution Approach 1:
The patent replaces the harmful chemical reagent (propane-2-thiol) with a non-invasive X-ray based measurement technique. The X-ray absorption spectroscopy method directly probes the sulfur crosslink structure in situ without requiring chemical cleavage, thereby eliminating the strong odor and safety issues associated with propane-2-thiol while maintaining the ability to analyze polysulfide bonds with n=2 to 8 sulfur atoms.
Solution Approach 2:
The patent uses X-rays as an intermediary to probe the sulfur crosslink structure. Instead of using chemical reagents that interact with and potentially alter the sample, X-rays serve as a non-contact intermediary that provides information about the sulfur atom environment through absorption spectroscopy, enabling polysulfide bond analysis without introducing harmful substances.
3Ease of manufacture
If only monosulfide and combined polysulfide crosslink densities are calculated, then the analysis is straightforward, but detailed control of sulfur crosslinked structure is insufficient for precise property control
Solution Approach 1:
The patent segments the polysulfide bond population into distinct categories based on the number of sulfur atoms (n=1 to n=8). By analyzing the X-ray absorption spectra and deconvoluting the contributions from different polysulfide bond types, the method provides individual crosslink density values for each bond type rather than a combined value. This segmentation enables detailed understanding and control of the sulfur crosslinked structure for precise property control.
Solution Approach 2:
The patent exploits parameter changes in X-ray absorption spectra that occur with varying sulfur atom numbers in polysulfide bonds. Each polysulfide bond type (n=1 to 8) exhibits characteristic absorption edge positions and fine structure parameters. By measuring and analyzing these spectral parameters, the method can differentiate and quantify each bond type, providing detailed crosslink structure information necessary for precise property control.
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
This method enables precise measurement of crosslink densities for each type of sulfide bond, enhancing the control over the mechanical properties of sulfur-containing polymer composite materials and providing more detailed information than previous methods.
Implementation Method 1
a measurement step of irradiating the sulfur-containing polymer composite material with high intensity monochromatic X-rays and measuring an X-ray absorption spectrum of the composite material while varying the energy of the X-rays
Implementation Method 2
a visualization step of determining a three-dimensional structure of sulfur atoms in the sulfur-containing polymer composite material by a reverse Monte Carlo method from the X-ray absorption spectrum
Data Source
Figure 1~2
Figure 3
AI summary
Provided is an evaluation method that provides detailed information on the crosslink densities in sulfur-containing polymer composite materials. The present invention relates to a method of measuring crosslink densities in a sulfur-containing polymer composite material, the method including: a measurement step of irradiating the sulfur-containing polymer composite material with high intensity X-rays and measuring an X-ray absorption spectrum of the composite material while varying the energy of the X-rays; a visualization step of determining the three-dimensional structure of sulfur atoms in the sulfur-containing polymer composite material by the reverse Monte Carlo method from the X-ray absorption spectrum; and a calculation step of calculating, from the three-dimensional structure of sulfur atoms, a crosslink density for each number of sulfur atoms bonded.