Boronic Ester Cross-linked Polymers for Recyclable Thermosets
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Solution Overview
Problem
Current polymer compositions that aim to combine the mechanical properties of thermosets with the processability of thermoplastics face challenges, as they often require the use of 1,2-diols or 1,3-diols, which lead to unwanted side reactions and complicate the manufacturing process, especially when trying to create materials that are insoluble at high temperatures and can be recycled without loss of mechanical properties.
Innovation Solution
The development of cross-linked polymer compositions featuring boronic ester functions that enable exchangeable cross-links through boronic ester metathesis reactions, allowing for the creation of polymers that are both thermoset-like in mechanical properties and thermoplastic-like in processability, without the need for 1,2-diols or 1,3-diols, using dioxaborolane and dioxaborinane rings and their derivatives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If 1,2-diols or 1,3-diols are used to create cross-linked polymer compositions, then mechanical properties similar to thermosets are achieved, but unwanted side reactions occur and manufacturing process is complicated
Solution Approach 1:
The patent changes the chemical parameter of the cross-linking mechanism by using boronic ester metathesis reactions instead of traditional diol-based cross-linking. This substitution eliminates the harmful side reactions (etherification, esterification) while maintaining the desired mechanical properties through reversible boronic ester bond formation and exchange reactions.
Solution Approach 2:
The patent extracts and removes the problematic 1,2-diols and 1,3-diols from the polymer composition system. By eliminating these specific diol components that cause unwanted side reactions, the invention achieves clean cross-linking without harmful byproducts while preserving the thermoset-like mechanical properties through alternative boronic ester-based cross-linking mechanisms.
2Strength
If traditional thermoset polymers are used, then mechanical strength and insolubility are achieved, but processability and recyclability are lost
Solution Approach 1:
The patent introduces dynamic and reversible boronic ester cross-links that can exchange and rearrange under processing conditions. This dynamic character allows the material to transition from a rigid thermoset network to a more processable state during manufacturing, enabling reshaping and recycling while maintaining strong mechanical properties when the cross-links are stable at service conditions.
Solution Approach 2:
The patent exploits parameter changes in the boronic ester cross-link stability with temperature and pH. At processing temperatures, the boronic ester bonds become more labile and exchangeable, enabling processability. At service temperatures, the bonds stabilize to provide thermoset-like strength and insolubility, thus resolving the contradiction between strength and processability.
3Stability of the object's composition
If 1,2-diols or 1,3-diols are used in polymer compositions, then cross-linking is achieved, but the number of parasite reactions increases especially at higher temperatures
Solution Approach 1:
The patent converts the potential harm of temperature-induced side reactions into a benefit by using boronic ester metathesis reactions that are specifically designed to be thermally activated. The reversible nature of boronic ester bonds allows controlled exchange reactions at processing temperatures without causing the unwanted etherification or esterification side reactions that plague diol-based systems, thus eliminating parasite reactions while maintaining cross-linking stability.
4Adaptability or versatility
If vinyl monomers carrying 1,2-diol or 1,3-diol functions are used, then cross-linking capability is achieved, but monomer stability during polymerisation deteriorates
Solution Approach 1:
The patent extracts and removes the unstable 1,2-diol and 1,3-diol functional groups from the vinyl monomer structure. By eliminating these problematic diol functions that cause polymerization instability, the invention achieves cross-linking capability through alternative boronic ester-functionalized monomers that maintain stability during the polymerization process while providing the desired cross-linking capability in the final polymer composition.
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
These polymer compositions can maintain mechanical properties similar to thermosets while being transformable at high temperatures and recyclable, overcoming the limitations of traditional thermosets and thermoplastics by enabling exchangeable cross-links that improve processability and recyclability.
Implementation Method 1
a new, rapid boronic ester metathesis reaction has been discovered that can be carried out at ambient temperature, with or without catalyst. Furthermore, the reaction is advantageously quantitative.
Implementation Method 2
They are thermoplastic at high temperature, that is to say they are transformable at high temperature
Data Source
Figure 1A~3
Figure 4~5
Figure 6~7
AI summary
The object of the invention is a polymer compositions comprising cross-linked polymer comprising boronic ester functions enabling exchange reactions, as well as free monofunctional boronic esters. These compositions arise from the polymerisation of precursor monomers to thermoplastic polymers comprising at least one pending boronic ester group, said pending boronic ester group not containing any polymerisable group and cross-linking agent comprising at least one boronic ester group enabling the formation of a network of cross-linked polymer containing pending functions and cross-links that are exchangeable by boronic ester metathesis reactions. Another object of the invention are processes for preparing this composition and materials and formulations comprising this composition.