Effect of cloisite 30B clay and sisal fiber on dynamic mechanical and fracture behavior of unsaturated polyester toughened epoxy network

Abstract

This study examined the dynamic mechanical properties of sisal fiber reinforced unsaturated polyester (UP) toughened epoxy nanocomposites. The chemical structures changes in Epoxy, UP and UP toughened epoxy (Epoxy/UP) systems were characterized by Proton Nuclear magnetic resonance ( 1 HNMR) spectroscopy. The morphological alterations of the nanocomposites were analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The untreated, chemically treated fibers, nanoclays, and the fiber reinforced Epoxy/UP nanocomposites were confirmed by FTIR spectrometer. The obtained mechanical results showed that alkali-silane treated fibers improve the tensile strength (96%) and flexural strength (60%) of the Epoxy/UP nanocomposite than that of Epoxy/UP blend due to the strong interfacial bonding between the sisal fiber and matrix. The fracture toughness (K IC ) and fracture energy (G IC ) of treated sisal fiber reinforced DGEBA/UP/C30B nanocomposites found to be higher than that of untreated sisal fiber nanocomposites. The dynamic mechanical analysis (DMA) reveals that the fiber reinforced Epoxy/ UP nanocomposites contains 30 wt% treated fiber and 1 wt% nanoclays, exhibits the highest storage modulus and better glass transition temperature (T g ) among the other kind of systems. The surface morphology of the fibers, fractured surface of the resins and composites were confirmed by scanning electron microscope (SEM). POLYM. COMPOS., 37:2832-2846, 2016. V C 2015 Society of Plastics Engineers

Unsaturated polyester-toughened epoxy composites: Effect of sisal fiber on thermal and dynamic mechanical properties

“…Prior to surface modification, the fibers were washed several times with ground water followed by a detergentdiluted solution at 40-50 o C to remove wax and other impurities and subsequently air-dried. Fourier-transform infrared (FTIR): O-H stretching (3,337 cm 21 ), C5O (1,732 cm 21 ), C-O stretching (1,299 cm 21 ), C-H asymmetric and symmetric stretching (2,899 cm 21 ), and CH 2 (1,430 cm 21 ) [28,29].…”

“…The fibers were then dried in the oven at 1058C for 24 h [6]. FTIR: O-H stretching (3,300 cm 21 ), C-H asymmetric and symmetric stretching (2,884 cm 21 ), and CH 2 (1,415 cm 21 ) [28,29].…”

Effect of Nanoclay on the Mechanical, Thermal, and Water Absorption Properties of an UP-toughened Epoxy Network

“…Several researchers have modified epoxies with flexible polymers and elastomers, resulting in improved macroscopic and microscopic properties [3][4][5][6][7]. In this study, unsaturated polyester (UP) resin was used to modify a brittle epoxy monomer to toughen it [8][9][10]. The toughening mechanism might decrease the thermal properties of the cured matrix.…”

Fabrication and evaluation of acrylated epoxidized castor oil‐toughened diglycidyl ether of bisphenol A nanocomposites

“…As observed from Figure 14, the fractured micrograph for epoxy (E) resin indicates a smooth-glassy microstructure with cracks in different planes, indicating the brittle nature and poor impact strength in the system. [69] As can be seen from Figure 14, crack propagation in the AC1-AC4 systems is lower, due to the plasticization effect. However, the ductile nature of the matrix increased with the addition of AECO to the DGEBA matrix.…”

“…Conversely, AECO act as elastomers to the brittle DGEBA resin and improve the toughening mechanism, as more energy is required to break the surface. [69] As can be seen from Figure 14, crack propagation in the AC1-AC4 systems is lower, due to the plasticization effect. This is attributed to the formation of nanocomposites, as the clay particles penetrate through the blend systems and form microvoids; hence plasticization increased.…”