In-situ infrared cure monitoring combined with two-trace two-dimensional (2T2D) correlation analysis to elucidate the matrix–filler interaction of nanocomposites: Case of thermosetting urethane/silica nanospheres

Abstract

A novel technique, in-situ infrared (IR) cure monitoring coupled with two-trace two-dimensional (2T2D) correlation analysis, is developed to probe the property-enhancement mechanism of a newly developed thermosetting nanocomposite comprising an acrylic-urethane network (AUN) and silica nanospheres (SNS). The IR spectra were collected in real-time during the curing process at 100 °C. We employ the 2T2D correlation analysis to identify the spectral variations of the interfacial interaction. The curing reaction initially proceeds throughout the sample solution. After the network percolation, the unreacted sites react near the SNS surface and yield additional hydrogen-bonded CO groups that interact with the surface silanol groups. The matrix–filler interactions play a key role in enhancing the hardness and thermal stability of the AUN/SNS nanocomposites by restricting the mobility of the polymer molecules. The proposed technique provides sequential mechanisms in the curing process and a picture of the interfacial interaction for the thermosetting nanocomposite system.

Keywords

• Silica nanosphere
• Thermosetting polymer
• Curing
• Matrix-filler interaction
• Two-trace two-dimensional correlation spectroscopy (2T2D)