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

APTES-functionalized bentonite for hierarchical reinforcement of gelatin films: enhanced mechanical, thermal, and barrier performance

Saba Falah, Mohammad Ghorbanpour, and Omid Rafeie

Faculty of Chemical and Petroleum Engineering, University of Tabriz, Tabriz, Iran

E-mail: Ghorbanpour@tabrizu.ac.ir

Received: 30 October 2025  Accepted: 8 December 2025

Abstract:

The demand for sustainable, biodegradable food packaging has driven the development of high-performance biopolymer films. This study presents 3-aminopropyltriethoxysilane (APTES)-functionalized bentonite as an effective hierarchical filler for gelatin films. Bentonite was modified with 10–20 wt% APTES, introducing reactive amine groups and hydrophobic alkyl chains. Addition of just 3 wt% APTES@Bentonite (with optimal 20 wt% APTES loading) significantly enhanced film properties. SEM showed uniform dispersion and exfoliated morphology, while FTIR and dramatic mechanical enhancement strongly suggest interfacial adhesion through hydrogen bonding and possible covalent Si–O–C linkages formed by condensation of residual silanol groups with gelatin hydroxyl/carboxyl groups. Optimized composite showed a 254% increase in tensile strength (from 6.89 to 24.39 MPa), higher thermal stability (+ 22 °C), 33% lower water vapor permeability, and 47% lower water solubility, albeit with reduced elongation at break. These enhancements arise from improved filler–matrix compatibility, covalent crosslinking, surface hydrophobization, and a tortuous diffusion pathway created by well-dispersed clay platelets. Notably, high optical transparency (~ 85% at 600 nm) and enhanced UV-blocking were retained. APTES-functionalized bentonite thus acts as a scalable, multifunctional filler, simultaneously reinforcing mechanical, thermal, and barrier properties of gelatin films, making them highly promising for next-generation eco-friendly food packaging applications.

Graphical abstract

Keywords: Gelatin films; APTES-modified bentonite; Biodegradable packaging; Mechanical reinforcement; Barrier properties

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04587-3

Chemical Papers 80 (5) 4805–4818 (2026)