Mechanical performance of e-glass reinforced polyester resins (isophthalic and orthophthalic) laminate composites used in marine applications

This study examined the mechanical performance of two polyester resins (isophthalic and orthophthalic) used to create e-glass-based laminate composites for the marine industry. The current study performed a static analysis of laminate composites using compressive, impact and hardness tests. Single edge-notched beam (SENB) fracture tests under mode I (i.e. opening mode) were performed on e-glass reinforced orthophthalic polyester laminate composites (S1) and e-glass reinforced isophthalic polyester laminate composites (S2) at cryogenic temperature (−10°C), ambient temperature (25°C) and high temperature (100°C). The interaction between fibres and matrix material was studied using Fourier transform infrared (FTIR) spectroscopy. A scanning electron microscope (SEM) was used to examine the substructure of fractured surface. A water absorption test was also performed on the fabricated samples. FTIR study revealed NH stretching, CH bend, CN stretching, C-O-C and CH-stretching. e-Glass isophthalic polyester composites had higher compressive strength, impact strength, hardness, fracture toughness and fracture energy than orthophthalic polyester laminate composites. The decrease in temperature increased the fracture properties. In both types of laminate composites, as the temperature increased, the fracture toughness and fracture energy decreased. The diffusion and permeability coefficients of isophthalic composites were greater than those of orthophthalic-based composites. The crushed fibre, fibre pull-out, riverline, matrix-fibre delamination and debonding are all evident in the fractured surface SEM micrograph.