Characterization of Locust Bean Seed Hull Extract (Gum) as a Bio-Binder for Natural Fiber Composites in Automotive Applications

Abstract

This study investigates the physicochemical and thermal characteristics of seed-hull extract to assess its suitability as a bio-based binder for automotive interior applications, particularly car consoles. The extract was subjected to Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric/Differential Thermal Analysis (TGA/DTA) following ASTM E1252-98 and ASTM E1131-20 standards, respectively. FTIR spectra revealed prominent absorption peaks associated with hydroxyl (–OH), carbonyl (C=O), and ether (C–O–C) groups, indicating the presence of functional groups capable of promoting strong interfacial interactions with reinforcing fibres and polymer matrices. TGA/DTA analysis showed an initial weight loss below 150 °C due to moisture evaporation, followed by major degradation between 250 °C and 380 °C, with significant char residue remaining at higher temperatures. These thermal transitions confirm that the seed-hull extract possesses adequate thermal stability for typical composite processing conditions in automotive manufacturing. Overall, the results demonstrate that seed-hull extract exhibits both desirable chemical functionalities and sufficient thermal resistance, making it a promising candidate for sustainable binder applications in automotive interior composite components.