Development of polymer composites become crucial in both industrial and research applications during the past few decades. As composite materials continue to advance, they will be able to replace metals and alloys in numerous fields, including packaging, electronics, automotive, structural, and many more, by acquiring materials with specific qualities and features. Polyamide 6 (PA6) is a semi-crystalline polymer with good heat resistance and a low coefficient of friction. Thus, from several decades, particularly PA6 material has been indispensable in a multitude of technical applications. However, PA6 suffered from its low melting point and high water absorption. Due to the hygroscopic nature the high-water absorption property of PA6 results in a decrease in dimensional stability and mechanical strength. As a result, water absorption enhances toughness and decreases stiffness and strength of PA6, significantly altering its (fracture) behaviour [1, 2]. Furthermore, prolonged exposure to high temperatures or light may cause this material to permanently lose its breaking strength, elongation, and toughness. In order to suit the requirement of materials with outstanding performance, reinforcements and polymer blending are frequent improvements. Amongst the various reinforcement for PA6, graphene, carbon fibers, and cellulose are most often used. However, very less data are reported regarding mineral fillers in PA6 in scientific literature. Particulate mineral fillers, such as kaolin, talc, mica, montmorillonite, CaCO3, and wollastonite, are the most often used fillers in composites because they lower costs and improves the stiffness of the material. Nevertheless, when correlating critical elongation and impact strength with unfilled polymers, the majority of research on the use of particle fillers in semi-crystalline polymers has reported a brittle effect. Polymer composites have been regarded as suitable materials for various engineering applications, given their excellent mechanical properties and processing abilities. Among polymers, Polyamide 6 (PA6) has gained considerable attention in the engineering community due to its remarkable properties such as high-temperature resistance, good chemical stability, high strength, and stiffness. However, with its hydrophilic behavior, PA6 suffers from water absorption, leading to a decrease in its mechanical properties. The incorporation of fillers such as borosilicate (BS) into PA6 composites has been seen as a viable solution to enhance the material's water absorption capability.
Borosilicates (BS) are naturally occurring oxygen-bearing boron minerals in which SiO₄ tetrahedra form a key structural element. They represent widespread constituents of rocks originating in the Earth’s crust. It has a high aspect ratio and a trigonal (acicular, needle) shape morphology. The high aspect ratio is responsible for high surface area and better stress transfer contributing to enhanced mechanical properties in polymer composites. It is expected that the addition of silicate minerals to the matrix plays an important role in making the material hydrophobic in nature. Borosilicate (BS) is a reinforcing material that has recently gained attention in the composites industry. It is a glassy material that is lightweight and provides excellent mechanical properties, making it an ideal potential candidate to be used as reinforcement for polymer composites. Therefore, in this paper, borosilicate (BS) was used as a filler and PA6 was used as the matrix to prepare PA6/BS composites by film casting technique. Furthermore, the effect of BS content on the water absorption, nucleation, thermal and tensile properties of the composites was analyzed. The interface mechanism of BS particles and the PA6 matrix was studied and the optimum BS addition amount was determined. This article aims to explore the various strategies used in improving the water absorption of PA6 composites reinforced with borosilicate.