1、Study on the reactivity and kinetics of primary and secondary amines

In this paper, an effective method for studying the reactivity and kinetics of primary and secondary amines in epoxy curing process by near-infrared (NIR) spectroscopy combined with multivariate analysis was proposed.

2、Investigation of the chemical changes and mechanism of the epoxy

It is generally agreed that the epoxy groups in epoxy resin react with amino groups to form new C–N and hydroxyl groups during the curing reaction process. However, detailed information about...

3、The Reactivity of Amines with Epoxy Resins: Factors and Optimization

Explore the chemical mechanisms of amine-epoxy reactions, including the roles of primary, secondary, and tertiary amines, and factors influencing reactivity rates. Learn how to optimize formulations for different applications and enhance epoxy curing with innovative strategies.

Comparative experiments on amine vs. acid anhydride curing

A high-pressure resin transfer molding injector has a limitation in that it can use only one type of curing agent—an amine or an acid anhydride species—owing to a chemical reaction occurring between the two curing agents when an epoxy composition is employed.

Chemical Resistance for Ambient Cure Epoxy Formulations

CHEMICAL RESISTANCE IN CONJUNCTION WITH OTHER ATTRIBUTES rapid development of hardness, or low temperature cure. Table 1 shows the handling and reactivity characteristics of the curing agents formulated wit standard bisphenol-A based (DGEBA) liquid epoxy resin. Data describing handling of the curing agent

(PDF) Curing of epoxy resins with amines

In this study, the mechanical properties of the epoxy resin, which is used in many fields, were observed with the addition of certain sizes of reactive and non-reactive diluents. Diglycidyl...

REACTIVITY STUDIES OF MALEIMIDE EPOXY RESIN WITH LONG CHAINED AMINES

The high reactivity of tetraethylenepentamine (TEPA) in these series of amines studied is due to the presence of five amine groups. Bishexamethylenetriamine (BHMT) which contains three amine group showed slightly less reactivity with epoxy compared tetraethylenepentamine (TEPA).

Waterborne Epoxy/Acrylic Resins Stabilized through the Neutralization

In this study, we develop a strategy combining chemical and blending methods to prepare stable waterborne epoxy/acrylic resins. First, the bisphenol A-based epoxy is end-modified with ETA through the ring-opening reaction of the epoxide with the primary amine on ETA.

Off

The cross-linking structure and physical properties of epoxy resins cured with amine under off-stoichiometric ratio conditions were examined.

On the Dielectric Behavior of Amine and Anhydride Cured Epoxy Resins

In the case of amine curing, epoxide groups react preferentially with primary amines, such that unreacted amine hydrogens will, in the form of secondary amines, tend to be located between network nodes, while unreacted epoxides will be present in the form of chain ends.

In the field of chemical materials science, resins are widely used as high-molecular-weight materials, and their modification with amines is a critical step to enhance performance. in practice, modified resins often exhibit poor reactivity, which not only reduces material effectiveness but also increases production costs and processing difficulties. This article explores the causes of poor reactivity after resin modification with amines and potential solutions.

I. Cause Analysis of Poor Reactivity After Resin Modification with Amines

1. Resin’s Molecular Structure Issues: The molecular structure of the resin directly affects its reactivity with amines. If the resin contains numerous unsaturated double bonds or triple bonds, these groups can hinder amine-resin interactions. Additionally, parameters such as molecular weight distribution and branching degree significantly influence reactivity.

2. Type and Concentration of Amine Used: Different amine compounds have varying reactivities. Some may undergo irreversible reactions with specific functional groups in the resin, reducing post-modification reactivity. High amine concentrations can also lead to excessive cross-linking, further impairing reactivity.

3. Improper Modification Processes: Factors such as temperature, reaction time, and catalyst usage during modification strongly impact outcomes. Inadequate process control (e.g., introducing impurities or unreacted substances) can degrade the resin’s performance.

II. Solutions and Practical Applications

1. Optimize Resin Selection and Pretreatment: Choose resins suitable for amine modification. For resins with unsaturated bonds, add stabilizers or cross-linkers to mitigate reactivity issues. Pretreating resins via drying or grinding removes moisture and impurities, improving amine compatibility.

2. Adjust Amine Type and Concentration: Select amines based on resin type and desired outcomes. Lower amine concentrations can prevent over-cross-linking. Multi-amine composite modifications, incorporating functional groups with different reactivities, may enhance overall reactivity.

3. Improve Modification Processes: Precisely control temperature, time, and catalyst dosage. High-efficiency catalysts accelerate reactions, while monitoring side reactions ensures unwanted products are minimized.

4. Post-Treatment and Functionalization: Post-modification steps like curing or cross-linking can improve mechanical properties and reactivity. Functionalization (e.g., introducing specific官能团 or altering surface properties) tailors the resin to application-specific needs.

5. Experimental Validation and Optimization: Test modified resins thoroughly to evaluate performance improvements. Iterate process adjustments based on experimental data to achieve optimal results.

Poor reactivity after resin modification with amines arises from complex interactions between the resin’s molecular structure, amine properties, and process conditions. By optimizing resin selection, adjusting amines, refining processes, and applying post-treatments, reactivity can be significantly improved. solutions must be tailored to specific contexts through experimentation and adjustment.