Propiedades tribológicas de una poliamida reforzada con butiral de polivinilo reciclado

Abstract

RESUMEN: En este estudio se analizó el comportamiento al desgaste de una poliamida ingenieril reforzada con fibra de vidrio (PA-GF) mezclada con distintas concentraciones de butiral de polivinilo reciclado (r-PVB). Las mezclas de PA-GF con el 0%, 10%, 15% y 20% de r-PVB (PA-0%, PA-10%, PA-15% y PA-20%, respectivamente) se fabricaron por moldeo por extrusión e inyección. Las propiedades mecánicas de las mezclas PA-GF/r-PVB-MA se estimaron mediante los ensayos de tensión y de dureza Shore D. La resistencia al desgaste se evaluó bajo la Norma ASTM G133-05 (Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear). Los ensayos de desgaste en la mezcla PA-20% mostraron una reducción en el CoF de ~27% y una disminución de la tasa de desgaste de ~70%, en comparación con la mezcla PA-0%. El diámetro de las partículas de r-PVB (~1.31 μm) y la distancia entre los bordes de las partículas de r-PVB (~0.40 μm), propiciaron el incremento en la resistencia al desgaste, por la aglomeración de las partículas sobre la huella de desgaste, evitando la fractura y la generación de escombros de las fibras de vidrio. Los mecanismos de desgaste en las mezclas PA-GF/r-PVB-MA fueron: cavidades, material adherido, fibra arrancada, fibra desprendida, fractura de fibra y escombros de fibra. ABSTRACT: In this study, the tribological performance of glass fiber-reinforced polyamide (PA-GF) and recycled polyvinyl butyral (r-PVB) blends was investigated. The PA-GF blends were prepared by melt-mixing and injection molding. Four different compositions were analyzed, namely PA-0%, PA-10%, PA-15%, and PA-20%, with varying amounts of r-PVB (0%, 10%, 15%, and 20%, respectively). Mechanical properties of the PA-GF/r-PVB-MA blends were determined using tensile testing and Shore D hardness. Ball-on-flat linear reciprocating wear tests were conducted according to ASTM G133-05 (Standard Test Method for Linearly Reciprocating Ball-on-Flat Sliding Wear) to evaluate the wear resistance. Results from the wear tests demonstrated that the PA-20% blend exhibited the highest wear resistance, with a reduction in coefficient of friction by approximately 27% and a decrease in wear rate by around 70%, compared to the PA-0% blend. The size of the r-PVB particles, diameters (~1.31 μm) and interparticle distances between the surfaces of two nearest neighboring particles (~0.40 μm), played a crucial role in improving the wear resistance. This phenomenon was attributed to the distribution and accumulation of r-PVB over the wear tracks, reducing the glass fiber fracture and generation of fiber debris. The main failure mechanisms on the wear tracks for the PA-GF/r-PVB-MA blends were cavities, adhered material, fiber debonding, fiber peel-off, fiber fracture, and fiber debris.