ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Optimization of alkaline treatment and hybrid MWCNT-SiO₂ nanofillers in basalt-glass fiber reinforced polymer composites

V. Boobalan and T. Sathish

Department of Mechanical Engineering, Saveetha School of Engineering, SIMATS, Chennai, India

E-mail: boopalanv4010.sse@saveetha.com

Received: 13 January 2026  Accepted: 2 March 2026

Abstract:

Optimizing alkaline treatment and hybrid nanofiller content is essential to enhance the mechanical performance of sustainable basalt/glass fiber reinforced polymer composites. In this study, Response Surface Methodology (RSM) based on a Box-Behnken Design (BBD) was employed to statistically model, predict, and optimize the processing parameters of hybrid basalt/glass fiber laminates reinforced with MWCNTs and nanosilica (SiO₂). Four key input factors including filler content (0–2 wt%), NaOH concentration (3–9 wt%), soaking time (3–9 h), and drying time (24–72 h) were investigated, while short beam shear strength (ILSS) and Vickers hardness were considered as output responses. Hybrid nanocomposite laminates with a 12-layer symmetric novel stacking sequence were fabricated using a manual lay-up followed by compression molding. Mechanical testing was carried out in accordance with ASTM D2344 and ASTM E384 standards. ANOVA results indicated that filler content was the most influential factor, followed by NaOH concentration, in improving mechanical performance. The optimized conditions predicted by the model yielded a maximum ILSS of 31.58 MPa and Vickers hardness of 20.47 kgf/mm² at 0.34 wt% filler, 3.28 wt% NaOH concentration, 7.49 h soaking time, and 42.04 h drying time. The close agreement between experimental and predicted values confirmed the adequacy of the quadratic models. SEM analysis revealed enhanced fiber-matrix interfacial bonding at optimal conditions, while excessive filler loading led to agglomeration and interfacial degradation. The study demonstrates the effectiveness of combined alkaline treatment and hybrid nanofiller reinforcement optimization, providing a systematic framework for tailoring lightweight hybrid composites with potential structural applications.

Keywords: Interlaminar shear strength; Box-Behnken design; Sustainable materials; Alkaline treatment; Vickers hardness

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04776-8

Chemical Papers 80 (6) 6449–6466 (2026)