Thermal degradation kinetics of resole phenol-formaldehyde resin/multi-walled carbon nanotube/cellulose nanocomposite

Abstract

This study investigated thermal degradation kinetics of multi-walled carbon nanotubes (MWCNTs) reinforced resole phenol-formaldehyde (PF) resin/cellulose nanocomposite, using thermogravimetry (TG) analysis as a function of the content or surface treatment of MWCNTs with or without a surfactant. FT-IR spectroscopy showed that the oxidation provided hydroxyl or carboxyl groups with MWCNT's surface while the silanization resulted in the silane attachment to MWCNT's surface. Conventional TG (CTG) thermograms demonstrated six thermal degradation steps, corresponding to various components of the nanocomposite, and also showed that the use of surfactant hastened thermal decomposition of the nanocomposite. The activation energy (E) obtained by the Kissinger method slightly increased as the MWCNT content increased while that of the cellulose degradation was independent on the MWCNT content. Both the oxidation and silanization treatments of MWCNTs’ surface resulted in an increase of the E values compared to that of the control sample. The activation energy (Eα) based on the isoconversional method increased up to α=0.5, and then was rapidly elevated to fluctuations. The activation energy (Em) based on the temperature modulated TG (MTG) analysis was within the range of the E value calculated by the Kissinger method for the thermal degradation of cellulose, a main component of the nanocomposite. These results show that MTG method provides similar activation energy to that of CTG method for thermal degradation of the nanocomposite, and indicate that MTG method be efficiently used to obtain activation energy without many scans from multiple heating rates.