Epoxidized castor oil toughened Diglycidyl Ether of Bisphenol A epoxy nanocomposites: structure and property relationships

Abstract

The present study highlights the structure and property relationships of epoxidized castor oil (ECO) toughened Diglycidyl Ether of Bisphenol A (DGEBA) epoxy nanocomposites. Toughened epoxy systems have been prepared by an addition of 10-40 wt% ECO to the DGEBA epoxy resin. Nanocomposites were prepared by mixing small amounts of Cloisite 30B (C30B) clay and 3-aminopropyltriethoxysilane to the DGEBA/ECO blends. The chemical structure of toughened systems was confirmed using proton nuclear magnetic resonance and fourier transform infrared spectroscopy. The triethylenetetraamine-cured DGEBA/ECO/C30B (8:2:0.1) nanocomposites exhibited tensile strength (50 MPa), tensile modulus (1.7 GPa), flexural strength (120 MPa), flexural modulus (3.02 GPa), and elongation (19%). The fracture toughness (critical intensity factor, K IC ) and fracture energy (critical energy release rate, G IC ) of DGEBA/ECO/C30B (8:2:0.1) system found to be higher than the other systems (2.5 MPa.m 1/2 and 1.8 kJ/m 2 for K IC and G IC , respectively). The thermal stability and heat of reaction of DGEBA/ECO blends increase with the addition of C30B clays that were analyzed using thermogravimetric analysis and differential scanning calorimetry. Rheological characterizations of uncured samples revealed a pronounced effect of the C30B clay on the DGEBA/ECO blend systems that exhibited a shear-thickening behavior. On the other hand, the dynamic mechanical properties also revealed that the addition of C30B clays to the DGEBA/ECO blend a significant enhancements in viscoelastic and cross linking density behavior. Scanning electron microscope analysis was used to study the fractured morphology of DGEBA, DGEBA/ECO, and its nanocomposite systems.

Synergistic effect of hybrid graphene and boron nitride on the cure kinetics and thermal conductivity of epoxy adhesives

“…Figure a shows the IR absorption spectra of different epoxy adhesive systems, where the three sets of adhesive system show their similar behavior. The IR spectra of neat epoxy show major peaks at 3356 cm −1 (O―H stretching), at 2922 (C―H asymmetric stretching) at 2852 cm −1 (C―H symmetric stretching), at 1720 cm −1 (C═O stretching), at 1411, 1382 and 1293 cm −1 (in‐plane bending vibrations of ―OH groups), at 1243 cm −1 (epoxy group), at 1179 cm −1 (C―O―C asymmetric stretching vibrations for ester), at 1031 cm −1 (aromatic C―O stretching) and the most intensive peak at 824 cm −1 attributed to the oxirane group of epoxy resin …”

“…This peak shifted to 829 cm −1 with the addition of 10 wt% of BN within epoxy/graphene adhesive system. Similar findings were observed by Paluvai et al in the case of diglycidyl ether of bisphenol‐A nanocomposites reinforced with epoxidized castor oil. A comparison of major functional groups of IR spectra of three different epoxy adhesive systems is shown in Table .…”

“…The IR spectra of neat epoxy show major peaks at 3356 cm À1 (O-H stretching), at 2922 (C-H asymmetric stretching) at 2852 cm À1 (C-H symmetric stretching), [56] at 1720 cm À1 (C═O stretching), at 1411, 1382 and 1293 cm À1 (in-plane bending vibrations of -OH groups), [57] at 1243 cm À1 (epoxy group), at 1179 cm À1 (C-O-C asymmetric stretching vibrations for ester), at 1031 cm À1 (aromatic C-O stretching) and the most intensive peak at 824 cm À1 attributed to the oxirane group of epoxy resin. [58] The IR spectra of epoxy/graphene adhesive showed major peak at 825 cm À1 , which indicate that graphene strongly reacts with epoxy. This peak shifted to 829 cm À1 with the addition of 10 wt% of BN within epoxy/graphene adhesive system.…”

Investigation on mechanical, thermal, and flame retardant properties of particulate SiO2 reinforced cardanol based composites

“…Craze on epoxy thermosetting materials by the polymeric world is due to their crosslinking characteristics, low shrinkage while curing, excellent thermal stability, acquiring good insulating, mechanical, chemical, and moisture resistant properties . These properties led to the breathless utilization of the polymer products in wide range of applications such as adhesives, coatings, matrix for high performance materials, aeronautics and automotive components and so forth .…”

“…Craze on epoxy thermosetting materials by the polymeric world is due to their crosslinking characteristics, low shrinkage while curing, excellent thermal stability, acquiring good insulating, mechanical, chemical, and moisture resistant properties. [1][2][3]7,[14][15][16][17] These properties led to the breathless utilization of the polymer products in wide range of applications such as adhesives, coatings, matrix for high performance materials, aeronautics and automotive components and so forth. [5,7] The drawbacks such as non-recyclability, environmental crises, and reprotoxic nature of bisphenol-A urge researchers to focus on renewable resources like vegetable oil and agricultural waste products as a raw material for developing sustainable high performance polymeric end products.…”