Degradable Latent Epoxy Curing Agents for Composite Recycling
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Solution Overview
Problem
The recycling of waste fiber composites is hindered by limitations in existing methods, including landfilling, incineration, and grinding, which result in environmental pollution, performance degradation, and high recycling costs, making effective and feasible recycling of composite materials a significant challenge.
Innovation Solution
Development of degradable latent epoxy curing agents and methods for synthesizing compounds and salts that allow for the degradation and recovery of reinforced composite materials, enabling the separation and reuse of matrix and reinforcing materials under mild reaction conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional epoxy resin curing agents are used to achieve high mechanical strength and durability, then the composite material becomes extremely hard and durable, but the cross-linked structure makes it particularly difficult to remove, recycling and reuse
Solution Approach 1:
The patent changes the chemical parameters of the curing agent by introducing degradable functional groups (such as ester groups, anhydride groups, or other hydrolyzable groups) into the curing agent structure. This allows the cross-linked network to be broken down under specific conditions (moisture, heat, or chemical treatment), enabling recycling while maintaining the original mechanical strength during service life.
Solution Approach 2:
The patent converts the previously harmful permanent cross-linked structure into a beneficial feature by designing a controllable degradation mechanism. The cross-linked structure provides strength during use, and upon exposure to specific conditions (such as moisture or heat), it degrades to allow recycling, thus converting the irreversibility from a disadvantage into a controllable feature.
2Ease of operation
If latent curing agents are used to improve storage stability and simplify production process, then one-component system achieves simplified operation and reduced environmental pollution, but the curing activity at room temperature remains insufficient
Solution Approach 1:
The patent applies preliminary action by pre-equipping the curing agent with latent reactivity that is activated under specific conditions. The curing agent is designed to remain stable during storage and transport but automatically activates when exposed to moisture, heat, or other environmental conditions, eliminating the need for separate mixing operations while maintaining adequate curing activity.
Solution Approach 2:
The patent introduces dynamics by designing a curing agent that transitions from a dormant state to an active state under specific conditions. The curing agent maintains low reactivity during storage for stability but exhibits high reactivity when triggered by moisture, heat, or other stimuli, enabling both easy handling and effective curing.
3Loss of substance
If traditional recycling methods (landfilling, incineration, grinding) are used to dispose of waste fiber composites, then waste management is achieved, but environmental pollution and performance degradation occur
Solution Approach 1:
The patent enables discarding and recovering by designing the composite material with a degradable matrix that can be broken down under specific conditions. This allows the reinforcing fibers to be separated and recovered for reuse, while the degraded matrix components can be processed into plastic products, eliminating the need for harmful landfilling or incineration methods.
Solution Approach 2:
The patent applies parameter changes by transforming the physical and chemical state of the composite material through controlled degradation. The material transitions from a stable cross-linked structure to a degraded state where the matrix can be separated from the fibers, enabling recovery and reuse while avoiding environmental pollution associated with traditional disposal methods.
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 degradable composite materials maintain high recovery efficiency of reinforcing materials, retain original mechanical properties, and can be reused, with the epoxy resin polymer degradation products suitable for plastic products, offering a high-quality recycling process that is economically viable and environmentally friendly.
Implementation Method 1
the crosslinking reaction of a polyamine compound with an epoxy resin usually is irreversible... Degradable latent epoxy resin curing agents are research focus... can quickly curing react... under certain conditions, the composite material is degraded
Data Source
AI summary
The present invention provides, among others, compounds of Formula (I) or a salt thereof, methods for making these compounds, degradable polymers and reinforced composites made therefrom, and methods for degrading and/or recycling the degradable polymers and reinforced composites.