Improved mechanical and antibacterial properties of polyvinyl alcohol composite films using quaternized cellulose nanocrystals as nanofillers

• Published in: Composites science and technology Vol. 232; p. 109885
• Main Authors: Meng, Lina, Li, Jiangwei, Fan, Xinyan, Wang, Yonggui, Xiao, Zefang, Wang, Haigang, Liang, Daxin, Xie, Yanjun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 08.02.2023
• Subjects: A. Bio composites; A. Polymer-matrix composites (PMCs); B. Interface; B. Multifunctional properties; A. Polymer-matrix composites (PMCs); B. Multifunctional properties; A. Bio composites; B. Interface
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2022.109885

Cellulose nanocrystals (CNC) are natural, renewable, and biocompatible materials that have been widely used as new sustainable reinforcing nanofillers in polymer composites. We present polyvinyl alcohol (PVA)/CNC composites with improved mechanical and antibacterial properties using CNC-based nanofillers. The surface esterified CNC (ECNC) was prepared by 6-bromohexanoyl chloride via surface esterification. Subsequently, the alkyl bromide group of the ECNC was transferred to quaternary ammonium groups for preparing quaternized CNC (ECNC-Qn) by introducing tertiary amino groups with different carbon chain lengths (C8–C16). Then, ECNC-Qn were blended with a PVA matrix to prepare PVA/ECNC-Qn nanocomposite films via a solvent casting procedure. Diverse features, including light transmission, mechanical properties, and antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria were investigated. Compared with pure PVA films, the PVA/ECNC-Qn nanocomposite films had higher tensile strength and higher antibacterial activity. Specifically, the maximum tensile strength and elongation at break of PVA/ECNC-Qn nanocomposite films were 45.4 MPa and 318.4%, respectively, which were 37.2% and 94.3% higher than those of pure PVA film, respectively. Moreover, the ECNC-Q8 exhibited the highest antibacterial efficiency, leading to the best antibacterial activity for PVA/ECNC-Q8 nanocomposite films among all films. This study demonstrates an efficient method for preparing a functional, environment-friendly PVA composite film. The prepared PVA/ECNC-Qn nanocomposite films exhibited considerable application potential in the packaging field, owing to their good mechanical and antibacterial barrier properties. [Display omitted] •The quaternized CNC (ECNC-Qn) were prepared via two-step surface modification.•ECNC-Qn were used as nanofillers to introduce multi-functions for PVA composites.•Both antibacterial and mechanical properties of PVA/ECNC-Qn films were enhanced.•The films showed almost 100% bactericidal efficiency against E. coli and S. aureus.