Microwave processing and characterization of EPON 862/CNT nanocomposites

In this research we have studied the cure behavior of epoxy resin system using microwave and regular oven heating in the presence and absence of multi-walled carbon nanotubes (CNTs). For this we have used a high temperature EPON 862 resin as matrix and CNTs as reinforcements. The EPON 862 Part A resin was reinforced with 0.1 wt%, 0.2 wt% and 0.3 wt% of CNTs using high intensity ultrasonic irradiation. The curing agent EPI Cure W (Part B) was mixed with EPON 862 resin using a non-contact mixing method (Thinky, Japan). In this technique the material container is set at 45° angle and revolves and rotates (2000 rpm) at the same time. Dual centrifugal forces were given to the material that keep pressing material to outward and down along with the slope of inner wall of the container. The trapped air and initial reaction volatiles were removed from the reaction mixture using a vacuum desiccator. Finally the mixture was cured using a 2.45 GHz (Sharp BP210) microwave oven for only 10 min instead of 8 h of conventional oven heating (curing schedule is 4 h at 120 °C and post-curing at 170 °C for 4 h). Thermal and flexural tests were performed for all samples including thermally cured and microwave cured epoxy samples of neat EPON 862, EPON 862/0.1 wt% CNTs, EPON 862/0.2 wt% CNTs and EPON 862/0.3 wt% of CNTs. The highest improvement (17%) in strength was found with only 0.2 wt% CNTs loading in EPON 862 as compared with the neat EPON 862 regular oven heating.