Organomodification of Indian bentonite clay and its influence on fire behavior of nanoclay/vinylester composites

Abstract

This article reports the organomodification of Indian bentonite clay with three modifiers and the fire behavior of organomodified Indian bentonite clay/vinylester/glass nanocomposites. Indian bentonite (Na-IB) clay was organomodified using hexadimethyl ammonium bromide (HDTMA-Br), tetra- n-butylammonium bromide (TBA-Br) and triphenyl methyl phosphonium bromide (TPP-Br) by varying the cation exchange capacity. Basal spacing of 34 Å was observed in Na-IB modified with HDTMA-Br (HDTMABr-IB) followed by 28 Å in Na-IB modified with TPP-Br (TPPBr-IB) and 26 Å in Na-IB modified with TBA-Br (TBABr-IB). Fourier transform infrared spectra of HDTMABr-IB confirmed the attachment of functional groups, its zeta potential increased from −36.34 to 5.35 mV indicating greater surface potential and thermogravimetric analysis showed greater weight loss confirming Na+ ion exchange with alkyl amines. Energy-dispersive X-ray analysis showed compositional changes between modified and unmodified clay with the presence of 37.03% carbon in the HDTMABr-IB. Horizontal and vertical burning rates of vinylester/glass composites decreased with the addition of HDTMABr-IB. Limiting oxygen index increased by 40% with the addition of 5 wt% HDTMABr-IB to vinylester/glass.