Polymer Processability Prediction via Molecular Weight Distribution
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Solution Overview
Problem
The existing methods for evaluating the processability of polyolefin resins, particularly for high-pressure pipes, are hindered by the need for expensive and error-prone die swell ratio measurements, which complicates the development of new resins with balanced long-term stability and processability.
Innovation Solution
A method using the molecular weight distribution curve, specifically through Equation 1, to predict the die swell ratio by calculating integral values across different sections of the GPC curve, providing a reliable alternative to direct measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the die swell ratio is measured using expensive analytical instruments, then the processability evaluation can be performed, but the measurement error is relatively large and the cost is high
Solution Approach 1:
The patent creates a mathematical model that copies the relationship between molecular weight distribution and die swell ratio. Instead of directly measuring die swell ratio with complex instruments, the model calculates it from GPC data, providing a simplified copy of the measurement process that avoids expensive equipment while maintaining evaluation accuracy
Solution Approach 2:
The patent replaces the mechanical measurement system (die swell ratio measurement using analytical instruments) with a computational system. The mathematical model substitutes physical measurement with calculation based on molecular weight distribution parameters, eliminating the need for complex measurement equipment
2Strength
If the molecular weight is high to prevent sagging during processing, then the processability improves, but the extrusion load is largely generated and pipe appearance is poor
Solution Approach 1:
The patent changes the approach from adjusting molecular weight (a single parameter) to optimizing the molecular weight distribution profile (multiple parameters). By controlling the distribution shape through the mathematical model, the patent achieves the desired strength-to-processability balance without the harmful effects of simply increasing molecular weight
Solution Approach 2:
The patent applies different molecular weight distribution characteristics to different parts of the distribution curve. The mathematical model identifies specific regions of the distribution that contribute to sagging resistance versus those that cause extrusion problems, allowing localized optimization of different molecular weight ranges
3Strength
If the density is high to improve high pressure resistance, then the modulus increases and strength to withstand high pressure increases, but the resistance against brittle fracture is deteriorated and long-term pressure resistance characteristic is deteriorated
Solution Approach 1:
The patent creates a composite molecular structure by combining different molecular weight components in specific proportions. The mathematical model guides the creation of a polyolefin resin that integrates high molecular weight components (for strength) with lower molecular weight components (for flexibility and fracture resistance), achieving a composite effect that balances high pressure resistance with long-term reliability
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to a method for predicting the physical properties of polymers. More specifically, the present invention relates to a method for predicting the processability of polymers using a molecular weight distribution curve.