Chemical modification of exfoliated graphite nanoplatelets with CTBN rubber and highly enhanced impact strength of vinyl ester resin by them

Abstract

In the present study, exfoliated graphite nanoplatelets (EGN) were chemically modified with carboxyl-terminated poly(butadiene-co-acrylonitrile) (CTBN) liquid rubber via carboxylation, acylation, and subse-quently esterification. Multiple characterizations by means of attenuated total reflectance-Fourier trans -form infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, X-ray diffraction spectroscopy, thermogravimetric analysis, and scanning electron microscopy demonstrated the chemical modification. For comparison, neat vinyl ester resin (VE), EGN/VE and CTBN-EGN/VE composites were prepared by using a free-standing Teflon mold to avoid pressure during curing. The amounts of EGN and CTBN-grafted EGN containing in EGN/VE and CTBN-EGN/VE composites were 1, 3, and 5 wt%, respec-tively. The impact strength of EGN/VE and CTBN-EGN/VE composites was strongly dependent upon the CTBN-grafted EGN concentration incorporated into neat VE. It was remarkably enhanced up to 220- 240% even with low contents (5 wt%) of CTBN-grafted EGN in comparison to neat VE and unmodified EGN/VE. The result revealed that a small amount of EGN chemically modified with liquid rubber CTBN played an important role in increasing the impact toughness of thermosetting resin. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.