Synthesis and characterization of 1, 1-bis (3-methyl-4-epoxyphenyl) cyclohexane-toughened DGEBA and TGDDM organo clay hybrid nanocomposites

Abstract

1,1-bis (3-methyl-4-epoxyphenyl) cyclohexane (BMEPC) was synthesized from 1,1-bis (3-methyl-4-hydroxyphenyl) cyclohexane and 2-(chloromethyl) oxirane, and its structure was confirmed by Fourier transform infrared (FT-IR), 1H-, 13C-NMR and electron impact-mass spectrometry. Both diglycidyl ether of bisphenol-A (DGEBA) and tetraglycidyl diamine diphenyl methane (TGDDM) epoxy resins were toughened with BMEPC using 4,4′-diaminodiphenylmethane (DDM) as a curing agent. Epoxy and BMEPC-toughened epoxy systems were further modified with organophilic MMT (OMMT) clay. The chemical reactions involved between epoxy and DDM with OMMT was confirmed by FT-IR. OMMT clay-filled hybrid BMEPC-epoxy resin castings were characterized for their mechanical, thermal, thermo-mechanical and morphological properties. The values of Tg and heat distortion temperature of hybrid epoxy decreased with increasing incorporation of OMMT. The data obtained from thermal studies indicated that the incorporation of nano clay into BMEPC-modified hybrid systems possess improved thermal stability. The mechanical properties were studied as per ASTM standards. The TGDDM-based hybrid epoxy system exhibited higher values of tensile and flexural properties than that of the DGEBA hybrid epoxy system, whereas the impact strength of the DGEBA system was higher when compared with that of the TGDDM system. The values of dielectric constant (ϵ′) and dielectric loss (ϵ′′) were increased with increased incorporation of OMMT clay in both systems. From the X-ray diffraction analysis it was observed that the absence of d001 reflections in OMMT-filled BMEPC-modified epoxy systems indicated the formation of exfoliated nano hybrids. The homogenous morphologies were ascertained from scanning electron microscope and transmission electron microscope.