Hemp cellulose nanocrystals for functional chitosan/polyvinyl alcohol-based films for food packaging applications

Kenza Bahsaine; Brahim El Allaoui; Hanane Benzeid; Mounir El Achaby; Nadia Zari; Abou El Kacem Qaiss; Rachid Bouhfid

doi:10.1039/d3ra06586c

Hemp cellulose nanocrystals for functional chitosan/polyvinyl alcohol-based films for food packaging applications

RSC Adv. 2023 Nov 13;13(47):33294-33304. doi: 10.1039/d3ra06586c. eCollection 2023 Nov 7.

Authors

Kenza Bahsaine^{1

2}, Brahim El Allaoui^{1

2}, Hanane Benzeid², Mounir El Achaby³, Nadia Zari^{1

4}, Abou El Kacem Qaiss^{1

4}, Rachid Bouhfid^{1

4}

Affiliations

¹ Moroccan Foundation for Advanced Science, Innovation and Research (MAScIR), Composites and Nanocomposites Center, Rabat Design Center Rue Mohamed El Jazouli, Madinat El Irfane 10100 Rabat Morocco r.bouhfid@mascir.com.
² Laboratoire de Chimie Analytique, Faculté de Médecine et de Pharmacie, Université Mohammed V de Rabat Rabat Morocco.
³ Materials Science and Nanoengineering Department (MSN), Mohammed VI Polytechnic University (UM6P) Lot 660 - Hay Moulay Rachid, 43150, Ben Guerir Morocco.
⁴ Mohammed VI Polytechnic University Lot 660 - Hay Moulay Rachid, 43150 Ben Guerir Morocco.

Abstract

Hemp is known for its swift growth and remarkable sustainability, requiring significantly less water, an adaptable cultivation to a wide range of climates when compared to other fibers sources, making it a practical and environmentally friendly choice for packaging materials. The current research seeks to extract cellulose nanocrystals (CNCs) from hemp fibers using alkali treatment followed by acid hydrolysis and assess their reinforcing capacity in polyvinyl alcohol (PVA) and chitosan (CS) films. AFM analysis confirmed the existence of elongated, uniquely nanosized CNC fibers. The length of the isolated CNCs was approximately 277.76 ± 61 nm, diameter was 6.38 ± 1.27 nm and its aspect ratio was 44.69 ± 11.08. The FTIR and SEM analysis indicated the successful removal of non-cellulosic compounds. Furthermore, the study explored the impact of adding CNCs at varying weight percentages (0, 0.5, 1, 2.5, and 5 wt%) as a strengthening agent on the chemical composition, structure, tensile characteristics, transparency, and water solubility of the bionanocomposite films. Adding CNCs to the CS/PVA film, up to 5 wt%, resulted in an improvement in both the Young's modulus and tensile strength of the bionanocomposite film, which are measured at (412.46 ± 10.49 MPa) and (18.60 ± 3.42 MPa), respectively, in contrast to the control films with values of (202.32 ± 22.50 MPa) and (13.72 ± 2.61 MPa), respectively. The scanning electron microscopy (SEM) images reveal the creation of a CS/PVA/CNC film that appears smooth, with no signs of clumping or clustering. The blending and introduction of CNCs have yielded transparent and biodegradable CS/PVA films. This incorporation has led to a reduction in the gas transmission rate (from 7.013 to 4.159 cm³ (m² day·0.1 MPa))^-1, a decrease in transparency (from 90.23% to 82.47%), and a lowered water solubility (from 48% to 33%). This study is the inaugural effort to propose the utilization of hemp-derived CNC as a strengthening component in the development of mechanically robust and transparent CS/PVA-CNC bio-nanocomposite films, holding substantial potential for application in the field of food packaging.