Production of Glass/Polypropylene Fiber-Reinforced Thermoplastic Lightweight Materials (LWRT)

Abstract The growing demand for sustainable, lightweight, and high-performance materials in industries such as automotive, aerospace, and construction necessitates innovative production processes. This study introduces a novel, entirely dry manufacturing method for lightweight reinforced thermoplastic (LWRT) panels, thereby offering an environmentally friendly and cost-effective alternative to conventional wet processes. Nonwoven fabrics with areal weights of 150 and 250 gsm, comprising a 50 wt% glass fiber (GF)-reinforced polypropylene (PP) matrix, were fabricated using a double carding technique, with the effect of subsequent needle punching on fiber bonding and homogeneity systematically investigated. A mixture of expandable microsphere foaming agent and PP powder was applied onto nonwoven fabrics; lamination was performed to induce foam formation at 220 °C and 1 m/min conveyor belt speed. SEM and microscopic analysis confirmed the impregnation of PP and the successful formation of microcellular structures through the foaming process, leading to a decrease in the panel density. Tensile and flexural strength were affected by the needle punching process and fabric areal weight. Panels made with 250 gsm nonwoven fabrics yielded mechanical properties similar to those of the commercial reference panel.