Polybenzoxazine/carbon nanotube nanocomposites as a polymeric sensing material for volatile organic compounds

Abstract

The emissions of volatile organic compounds (VOCs) have hazardous effects on humans and the environment, and hence they should be detected and reduced. In this study, polybenzoxazine (PBZ) and amine-functionalized multiwall carbon nanotube (MWCNT) composites were synthesized as a sensor for VOCs. MWCNT were functionalized with two types of diamines, namely, 1,6-hexanediamine (HDA) and phenylenediamine (PDA). HDA or PDA treated MWCNTs were loaded into the benzoxazine matrix with different weight percentages (0.1, 0.3, 0.5, and 1%). FTIR analysis confirmed the chemical attachment of the two types of diamines on MWCNT. XRD diffraction and scanning electron microscopy (SEM) were used to investigate the nanofillers morphology and clarify the differences between pristine and amine-functionalized MWCNT. Thermal gravimetric analysis (TGA) was used to study the composites’ thermal stability and degradation behavior. It was found that, in contrast to neat PBZ, the major degradation temperature of PBZ/0.5%MWCNT-PDA nanocomposites were enhanced by 10%. The electrical conductivity of PBZ was 6.32 × 10–9, which was enhanced to 6.11 × 10–7 in the composites with 1% MWCNT-PDA. This material was tested as a VOCs sensor for methanol, acetone, and toluene and showed that PBZ/1% MWCNT-PDA composite responded to all the vapors.