Preparation of Nanocellulose Reinforced Chitosan Films, Cross-Linked by Adipic Acid

• Published in: International journal of molecular sciences Vol. 18; no. 2; p. 396
• Main Authors: Falamarzpour, Pouria, Behzad, Tayebeh, Zamani, Akram
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13.02.2017; MDPI
• Subjects: Acetic acid; Acids; Activation energy; Adipates - chemistry; adipic acid; Amides - chemistry; Biopolymers; Cellulose; Cellulose - chemistry; Chitosan; Chitosan - chemistry; cross-linking; Cross-Linking Reagents - chemistry; Fourier transforms; Glycerol; Kinetics; Mechanical Phenomena; Mechanical properties; Membranes, Artificial; nanocomposite film; Nanoparticles - chemistry; Nylon; Spectroscopy, Fourier Transform Infrared; Tensile strength; chitosan; adipic acid; nanocomposite film; cross-linking; mechanical properties; acetic acid
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms18020396

Adipic acid, an abundant and nontoxic compound, was used to dissolve and cross-link chitosan. After the preparation of chitosan films through casting technique, the in situ amidation reaction was performed at 80-100 °C as verified by Fourier transform infrared (FT-IR). The reaction was accompanied by the release of water which was employed to investigate the reaction kinetics. Accordingly, the reaction rate followed the first-order model and Arrhenius equation, and the activation energy was calculated to be 18 kJ/mol. Furthermore, the mechanical properties of the chitosan films were comprehensively studied. First, optimal curing conditions (84 °C, 93 min) were introduced through a central composite design. In order to evaluate the effects of adipic acid, the mechanical properties of physically cross-linked (uncured), chemically cross-linked (cured), and uncross-linked (prepared by acetic acid) films were compared. The use of adipic acid improved the tensile strength of uncured and chemically cross-linked films more than 60% and 113%, respectively. Finally, the effect of cellulose nanofibrils (CNFs) on the mechanical performance of cured films, in the presence of glycerol as a plasticizer, was investigated. The plasticized chitosan films reinforced by 5 wt % CNFs showed superior properties as a promising material for the development of chitosan-based biomaterials.