HT-TGIC Thermal Gradient for Polymer Resolution
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Solution Overview
Problem
Current chromatography techniques for analyzing the comonomer content and distribution (CCD) of olefin-based polymers suffer from limited resolution and coelution issues, leading to inaccurate short chain branching distribution (SCBD) results.
Innovation Solution
A modulated thermal gradient profile is applied in high temperature thermal gradient interaction chromatography (HT-TGIC) to enhance the resolution and accuracy of CCD analysis, improving the characterization of olefin-based polymers by increasing the Resolution Index (RI) of chromatograms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional crystallization-based techniques (CEF, TREF) or HT-TGIC are used for CCD analysis, then the analysis can be performed, but the resolution is limited and coelution occurs leading to inaccurate SCBD results
Solution Approach 1:
The patent applies dynamic temperature modulation during the chromatographic process, using multiple heating and cooling cycles to dynamically adjust the separation conditions. This dynamic approach allows different polymer fractions to be separated at different temperature stages, improving resolution and eliminating coelution issues that occur with static temperature methods
Solution Approach 2:
The invention employs periodic heating and cooling cycles (typically 2-5 cycles) during the HT-TGIC process. Each cycle consists of heating to a specific temperature, holding, cooling, and holding at low temperature. This periodic action enhances the separation of polymer fractions with similar microstructures by repeatedly adjusting the thermodynamic conditions, thereby improving measurement precision
2Productivity
If standard HT-TGIC method is used, then CCD analysis is performed, but coelution issues reduce the accuracy of SCBD results
Solution Approach 1:
The patent systematically changes multiple parameters including temperature profiles (heating rates, holding temperatures, cooling rates), cycle numbers, and stationary phase characteristics. By optimizing these parameters, the method achieves both high productivity through efficient separation and high measurement precision through improved resolution that eliminates coelution
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 method significantly improves the resolution and accuracy of CCD analysis, reducing coelution and enhancing the characterization of polymer microstructures compared to existing techniques like CEF, TREF, and TGIC-h-GPC.
Implementation Method 1
high temperature thermal gradient interaction chromatography (HT-TGIC)
Implementation Method 2
interaction based techniques (high temperature thermal gradient interaction chromatography, HT-TGIC
Data Source
Figure 1~2A
Figure 2B~3
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AI summary
A method increase of the Resolution Index (Rl) of a chromatogram generated from a polymer sample comprising at least two olefin-based polymers of different microstructures and/or at least two olefin-based polymer fractions of different microstructures. The method comprises separating the mixture on a low-porosity stationary phase and repeatedly cycling the sample-stationary phase through a series of cooling and heating stages with active eluent flow only during the cooling stages and during the last heating stage to elute the separated analytes off the column.