Impact of temperature aging on behavioral changes in vinyl ester composite reinforced with Himalayan nettle fiber and silicious rock dust

Abstract

This study investigates the mechanical, wear, thermal, and flammability properties of vinyl ester composites reinforced with Himalayan nettle fiber and silicious rock dust, with a particular focus on the effects of thermal aging at 50 °C for 30 days. The composites were fabricated using a lay-up technique, with various ratios of vinyl ester resin, nettle fiber, and silicious rock dust, creating specimens designated as R, RN, RN0, RN1, RN2, and RN3. Among these, specimen RN3, containing 50 Wt.% nettle fiber and 4 Wt.% silicious rock dust, demonstrated superior performance. RN3 exhibited a tensile strength of 139 MPa, flexural strength of 151 MPa, hardness of 83 Shore-D, and an Izod impact strength of 5.5 J, indicating significant improvements due to the effective load transfer from the matrix to the fibers and the reinforcing effect of the filler. RN3 also showed the lowest specific wear rate of 0.0012 mm³/Nm and a coefficient of friction of 0.14, primarily due to the abrasive-resistant nature of the silicious rock dust and its ability to enhance load distribution. Thermogravimetric analysis revealed that RN3 had a weight loss at maximum degradation of 99% and a degradation temperature of 386 °C, highlighting its enhanced thermal stability. Additionally, RN3 exhibited the lowest flame propagation speed of 3.7 mm/min, maintaining a UL-94 V-0 rating, making it particularly suitable for high-safety applications. Optical microscopic scanning of wear surfaces further confirmed the effectiveness of silicious rock dust filler in reducing wear damage and improving fiber-matrix adhesion, which contributed to the overall durability of the composite. This study demonstrates the potential of using industrial waste particles and natural fibers in reinforcing composites for improved mechanical and thermal properties, particularly in applications requiring long-term stability and resistance to wear and fire.