# Range-Aware Two-Stage Modeling for Feed Ratio Optimization in Fluoroelastomers: Mechanistic Pathways from NMR Structural Features to Macroscopic Properties

## TL;DR

This paper introduces a new method for optimizing fluoroelastomer feed ratios by linking NMR structural features to material properties, improving prediction accuracy and reducing errors.

## Contribution

The RATS method introduces a two-stage modeling approach that enables mechanistic pathway analysis for feed ratio optimization in fluoroelastomers.

## Key findings

- RATS achieved an average R2 of 0.90 across four property predictions, outperforming direct modeling.
- The method identified 72 systematic transmission pathways, including the promoting effect of PMVE-series structures and the inhibitory effect of VDF monomers.
- RATS reduces prediction error by 28% and provides a data-guided alternative to empirical trial-and-error methods.

## Abstract

This study developed the RATS (Range-Aware Two-Stage) modeling approach to establish mechanistic foundations for feed ratio optimization in fluoroelastomers. Using 19F NMR spectroscopic analysis, the approach decomposes complex composition–property relationships into sequential processes: monomer feed ratios to NMR-derived structural features, and structural features to properties, enabling mechanistic pathway analysis through quantifiable structural intermediates. Using 52 industrial datasets, RATS achieved an average R2 of 0.90 across four property predictions, representing a 0.14 improvement over direct modeling and a 28% reduction in prediction error. The approach identified 72 systematic transmission pathways, including promoting effects of PMVE-series structures (+0.220 influence strength) and inhibitory effects of VDF monomers (−0.219 influence strength), through quantified model parameter analysis. This methodology provides a practical analytical tool for mechanism-driven feed ratio optimization, facilitating the transition from empirical trial-and-error to systematic, data-guided fluoroelastomer formulation.