2022 Annual Meeting

Evaluating the Curing Kinetics of Composite Phenolic Resins and Coal Using Differential Scanning Calorimetry

Phenolic resin, a low-weight and heat-resistant thermosetting polymer, is an essential material in various industries. It is highly valued for its cost-effective nature whilst enforcing favorable mechanical characteristics. Phenolic resin is often integrated with compatible fillers to support its cured brittle structure, allowing for sturdy and enhanced composites. With the rising concern of carbon emissions due to coal consumption, coal is a primary filler candidate as it is compatible with phenolic resin due to its similar structures. This study aims to determine how varying conditions affect the curing kinetics of phenolic resin and different ranks of coal using differential scanning calorimetry. These thermodynamic analyses can be used as a foundation for fabricating phenolic resin composites as the curing behavior will determine the process conditions for manufacturing components at scale.

The powder phenolic resin and the sieved Powder River Basin (PRB) and Itmann coal were mixed in varying weight percentages, 100%, 90%, and 60% phenolic resin. These samples were then heated from 50 °C-250 °C using a Mettler Toledo HP DSC 2+ under heating rates ranging from 5 °C/min - 20 °C/min (three samples per heating rate). Heat flow (W/g), time (s) and temperature (°C) data were collected and used to establish the cure profiles for each sample. The degree of cure for the resin samples was determined using the DSC STARe evaluation software. With the extracted conversion data, a MATLAB program calculated the activation energy of curing using the Akahira-Sunrose-Kissinger Method and the Friedman Method.

The graphs that will be presented display the activation energy values against the degree of cure for all composites and the pure solid phenolic resin using the Kissinger and Friedman Methods. It should be noted that as the percentage of Itmann coal increases within the sample, the activation energy decreases. Meanwhile, PRB coal and phenolic mixtures’ activation energy values increase over the composite’s conversion profile. These trends are analyzed by evaluating the chemical and structural variances between the two ranks of coal and their reactions with the solid phenolic resin. The analysis of the resulting data focused on potential reactive functional groups and active sites, and how their presence and absence affect activation energy. Further explanation of the activation energy methods and curing kinetics will be displayed during the poster session.