Effects of fabrics reinforced on mechanical properties of epoxy epikote 828

Micro‐sized luffa cylindrica fibers (MLCFs) are made from raw luffa natural fibers from Vietnam and are environmentally friendly while possessing good mechanical strength. This work focuses on the mechanical properties of composite based on epoxy epikote 828 reinforced with MLCFs, particularly the fracture toughness. The results show that the MLCFs content has a great influence on the fracture toughness, especially the critical‐stress intensity factor (KIC) and izod impact strength of composite. Specifically, when using MLCFs reinforced from 0 to 2.0 wt.%, the critical‐stress intensity (KIC) increased from 1.89 to 4.60 MPa.m1/2, while the izod impact strength increased from 3.6 to 7 KJ/m2, respectively. The thermal behavior of the composite reinforced with MLCFs at different contents was determined using thermogravimetric analysis (TGA). The surface fracture structure of the composite samples was determined using scanning electron microscopy (SEM) method.

Effect of micro‐sized luffa cylindrica fibers on the mechanical properties of epoxy epikote 828

Trung,

Huu,

Anh

et al. 2023

Effect of sodium hydroxide treatment on the fracture toughness of luffa natural fiber reinforced epoxy epikote 828

Trung,

Oanh

2024

Micro‐sized luffa natural fibers (MLNFs) were derived from raw luffa natural fibers from Vietnam by undergoing treatment with sodium hydroxide. This study examined the impact of sodium hydroxide concentration, temperature, and treatment duration on the fracture toughness of epoxy resin 828 reinforced with MLNFs. The results showed that the fracture toughness of the composite, as measured by the critical‐stress‐intensity factor (KIC) and Izod impact strength, was improved after the treatment of the MLNFs with sodium hydroxide. Specifically, with the optimal sodium hydroxide treatment parameters of 6% NaOH at 70 °C for 6 h, the critical‐stress‐intensity factor increased by 93% (from 2.0 to 3.86 MPa m1/2) and the Izod impact strength rose by 44.6% (from 3.81 to 5.51 kJ/m2). The thermal properties and surface structure of MLNFs treated with NaOH were analyzed using thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) images.

Improved fracture toughness of epoxy resin reinforced with micro‐sized lotus fibers pre‐ and post‐sodium hydroxide treatment

Trung

2024

Micro‐sized lotus fibers (MLFs) are derived from Vietnamese lotus plant stems, making them eco‐friendly. The composition of MLFs includes wax, oil, lignin, hemicellulose, and cellulose. The purpose of sodium hydroxide treatment is to remove unwanted components in MLFs like wax, oil, lignin, etc., to clean and roughen the surface, increase thermal stability, and enhance adhesion between MLFs with epoxy resin to improve the fracture toughness of the composite. The study investigated the impact of sodium hydroxide concentration, temperature, and treatment duration on the fracture toughness of epoxy resin reinforced with MLFs. Results indicated that treating lotus fiber with sodium hydroxide enhanced the biocomposite's fracture toughness, as indicated by the critical‐stress‐intensity factor (KIC) and Izod impact strength. Optimal treatment conditions of 80 °C at 6% NaOH for 6 h led to a 91% increase in the critical‐stress‐intensity factor (from 2.0 to 3.82 MPa m1/2) and a 121% rise in Izod impact strength (from 4.32 to 9.56 kJ/m2). Thermal properties (TGA) and structural morphology (SEM) of micro‐sized lotus fibers pre‐ and post‐sodium hydroxide treatment were evaluated using thermogravimetric analysis and scanning electron microscopy images.