ABA Block Co-Polymer Polyol Phase Separation
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Solution Overview
Problem
Existing polyurethane formulations using random co-polymer polyols often experience randomization reactions during synthesis, leading to unpredictable distribution of components and resulting in suboptimal physical properties such as Shore A hardness, tensile strength, and elongation.
Innovation Solution
The use of an ABA block co-polymer polyol, where the B block comprises at least one dimer fatty residue and each A block consists of a plurality of hydroxy-carboxylic acid residues, maintained through ring-opening polymerization of lactones onto the B block, to phase-separate and enhance the polyurethane's physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a random co-polymer polyol is used in polyurethane synthesis, then the synthesis process is simpler, but the distribution of components becomes randomised leading to suboptimal physical properties
Solution Approach 1:
The polyol is segmented into distinct blocks (A blocks containing hydroxy-carboxylic acid residues and B blocks containing dimer fatty acid residues) rather than having a random distribution. This segmentation is achieved through controlled ring-opening polymerization of lactones onto a dimer fatty acid-based polymer, creating an ABA block co-polymer structure that maintains component distribution control while simplifying the synthesis process.
Solution Approach 2:
Different regions of the polyol molecule are given different local qualities - the A blocks provide polar regions with hydroxy-carboxylic acid residues that enhance hardness and chemical resistance, while the B blocks provide non-polar regions with dimer fatty acid residues that contribute to flexibility and processability. This local differentiation of properties within the polyol structure enables optimized physical properties in the final polyurethane product.
2Productivity
If transesterification reaction occurs during polyol synthesis, then the reaction proceeds readily, but the ABA block structure is randomised reducing phase separation and physical properties
Solution Approach 1:
The synthesis conditions are carefully controlled by adjusting parameters such as temperature, catalyst selection, and reaction sequence to promote ring-opening polymerization while suppressing transesterification. The ring-opening polymerization of lactones onto the dimer fatty acid-based polymer is conducted under conditions that maintain the ABA block structure, thereby preserving the phase-separated morphology needed for optimal physical properties while still achieving productive reaction rates.
3Strength
If phase separation between polar and non-polar regions is enhanced, then mechanical properties are improved, but the synthesis process becomes more complex
Solution Approach 1:
The polyol is designed as a block co-polymer composite structure where A blocks (hydroxy-carboxylic acid residues) and B blocks (dimer fatty acid residues) are distinctly separated into different regions. This composite structure promotes phase separation in the final polyurethane product, enhancing mechanical properties such as hardness, tensile strength, and elongation. The synthesis achieves this complex structure through controlled ring-opening polymerization, which systematically builds the ABA block architecture without requiring overly complex synthesis procedures.
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 approach results in polyurethanes with improved Shore A hardness, tensile strength, and elongation, as the ABA sequence maintains the non-polar and polar regions' phase separation, providing enhanced mechanical properties compared to polyurethanes made with random co-polymer polyols.
Implementation Method 1
The ABA order of the block co-polymer may allow these non-polar and polar regions to phase separate in a polyurethane formed from the co-polymer polyol which may improve one or more physical properties of the polyurethane
Implementation Method 2
forming each A block on the B block by ring opening polymerisation of at least one lactone on to the B block
Data Source
AI summary
The present invention provides a co-polymer polyol which has an ABA block structure wherein each A block comprises a plurality of hydroxy-carboxylic acid residues and the B block comprises at least one dimer fatty residue selected from a dimer fatty diacid residue, a dimer fatty diol residue and a dimer fatty diamine residue, wherein the co-polymer polyol comprises at least two hydroxyl end groups. The invention also provides a method of making the co-polymer polyol and a polyurethane comprising the co-polymer polyol.