Biocomposite Fabrication from Enzymatically Treated Nanocellulosic Fibers and Recycled Polylactic Acid

Mohamed Amine Laadila,Rosa Galvez,Tarek Rouissi,Colin Jacob,Gayatri Suresh,Ridha Ben Cheikh,Pratik Kumar,Satinder Kaur Brar,Kofi Abokitse

doi:10.3390/en13041003

Abstract

Recycled polylactic acid (PLAr) was reinforced with treated nanocellulosic hemp fibers for biocomposite fabrication. Cellulosic fibers were extracted from hemp fibers chemically and treated enzymatically. Treated nanocellulosic fibers (NCF) were analyzed by Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Biocomposite fabrication was done with PLAr and three concentrations of treated NCF (0.1%, 0.25%, and 1% (v/v)) and then studied for thermal stability and mechanical properties. Increased thermal stability was observed with increasing NCF concentrations. The highest value for Young’s modulus was for PLAr + 0.25% (v/v) NCF (250.28 ± 5.47 MPa), which was significantly increased compared to PLAr (p = 0.022). There was a significant decrease in the tensile stress at break point for PLAr + 0.25% (v/v) NCF and PLAr + 1% (v/v) NCF as compared to control (p = 0.006 and 0.002, respectively). No significant difference was observed between treatments for tensile stress at yield.

Highlights

Polylactic acid (PLA) is one of the most commonly fabricated bioplastics in the last decade.Its mechanical properties, renewability, relatively low cost, and biodegradability make PLA ideal for its use as a biopolymer in the fabrication of biomaterials and decomposable packaging materials and in the automotive industry [1]
The after thethe fermentation, andand the highest laccase activity was was obtained after days of fermentation using blueberry pomace, which is obtained after 10 days of fermentation (34.02 ± 1.95 U/gds) using blueberry pomace, which is comparable to the results reported by Trichoderma reesei was used to produce comparable to the results reported by Chaali and Lecka [20]
The enzymatic treatment was effective for the improvement of reactive sites between nanocellulosic fibers (NCF) and PLAr matrix, which was confirmed by the increase in the hydrogen bonding

Summary

Introduction

Polylactic acid (PLA) is one of the most commonly fabricated bioplastics in the last decade.Its mechanical properties (such as a high Young’s modulus), renewability, relatively low cost, and biodegradability make PLA ideal for its use as a biopolymer in the fabrication of biomaterials and decomposable packaging materials and in the automotive industry [1]. Its use is limited due to its sensitivity to moisture and low impact resistance. These bioplastics have several disadvantages, such as low crystallization ability, thermal degradation, longer residence time in the extruder and shredding process, which decreases its mechanical and physical properties after several recycling cycles [2]. This can be addressed by the addition of nanosized reinforcing fillers to the PLA matrix to form nanocomposite materials with improved physical, mechanical, and thermal properties [3]. Natural fibers can be an attractive candidate as reinforcement of biocomposites, as in Energies 2020, 13, 1003; doi:10.3390/en13041003 www.mdpi.com/journal/energies

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Discussion

Conclusion