Epoxybenzyl-Terminated Poly(arylene Ether) for Room Temperature Curing
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Solution Overview
Problem
Epoxy resin compositions with poly(arylene ether) face challenges such as brittleness, premature curing, and poor solvent resistance due to low reactivity of phenolic end groups, which require high temperatures and additional processing steps, and involve the use of environmentally undesirable chemicals like epichlorohydrin.
Innovation Solution
Development of epoxybenzyl-terminated poly(arylene ether) that is highly reactive at room temperature, eliminating the need for up-staging and reducing the use of epichlorohydrin, resulting in improved solubility, single-phase polymer morphology, and enhanced solvent resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydroxyl-terminated poly(arylene ether) is used to reduce brittleness of epoxy resin, then impact strength is improved, but reactivity with epoxy resin is poor requiring high temperatures and long times for curing
Solution Approach 1:
The patent modifies the chemical structure of poly(arylene ether) by replacing hydroxyl terminal groups with carboxyl terminal groups. This parameter change in functional group chemistry enables the polymer to react with epoxy resin at room temperature without catalysts, solving the contradiction between maintaining impact strength and achieving practical curing speeds.
Solution Approach 2:
The carboxyl group acts as an intermediary functional group that facilitates reaction between poly(arylene ether) and epoxy resin. The carboxyl-epoxy reaction proceeds readily at room temperature, serving as an effective intermediary mechanism that overcomes the poor reactivity of hydroxyl groups while maintaining the desired mechanical properties.
2Strength
If high molecular weight poly(arylene ether) is used to reduce brittleness, then impact strength is improved, but solubility in epoxy resin deteriorates requiring high temperatures for dissolution
Solution Approach 1:
The patent changes the terminal functional group parameter from hydroxyl to carboxyl, which significantly improves solubility in epoxy resin. This functional group modification enables high molecular weight poly(arylene ether) to dissolve readily in epoxy at room temperature without requiring high temperature processing, while maintaining the impact strength benefits of high molecular weight polymer.
3Stability of the object's composition
If phenolic end groups are used in poly(arylene ether), then water resistance is maintained, but reactivity with diamine hardeners is poor causing preferential epoxy-diamine reaction
Solution Approach 1:
The patent changes the terminal functional group from phenolic hydroxyl to carboxyl, fundamentally altering the reaction chemistry. Carboxyl groups react readily with both diamine hardeners and epoxy resins at room temperature, enabling effective incorporation of poly(arylene ether) into the cured matrix while maintaining the water resistance characteristics of the aromatic ether backbone structure.
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 epoxybenzyl-terminated poly(arylene ether) ensures better incorporation into the epoxy matrix, improving impact strength and solvent resistance, and reducing water absorption, while simplifying processing and avoiding the use of harmful chemicals.
Implementation Method 1
epoxybenzyl-terminated poly(arylene ether)s...ensures better incorporation into the epoxy matrix
Implementation Method 2
reacting the vinylbenzyl-terminated poly(arylene ether) with a peracid to form an epoxybenzyl-terminated poly(arylene ether)
Data Source
AI summary
An epoxybenzyl-terminated poly(arylene ether) has the structure R—W—R wherein W is a divalent poly(arylene ether) residue terminated with phenolic oxygen atoms, and R is an epoxybenzyl group, wherein each occurrence of R is the same or different. The epoxybenzyl-terminated poly(arylene ether) is formed by reacting a peroxide-containing reagent with a vinybenzyl-terminated poly(arylene ether). Also disclosed is a curable composition including the epoxybenzyl-terminated poly(arylene ether)s, a curing promoter, and, optionally, an auxiliary epoxy resin. The curable composition is useful for the preparation of composites, and in particular, composites used in manufacturing printed circuit boards.