Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared by Melt Processing

Abstract

Cellulose nanocrystals (CNCs) were surface modified by esterification in tetrahydrofuran (THF) at 25 °C using different catalysts and anhydrides bearing different alkyl side chain lengths. Unmodified and acetic anhydride (AcAnh)-modified CNCs were studied as potential nanofillers for linear low-density poly(ethylene) (LLDPE). Nanocomposites were prepared by melt processing. Determination of the size and size distribution of CNCs in the nanocomposites by SEM revealed an enhanced compatibility of the AcAnh-modified CNCs with the LLDPE matrix, since the average size of the aggregates of the modified CNCs (0.5–5 μm) was smaller compared to that of the unmodified CNCs (2–20 μm). Tensile test experiments revealed an increase in the nanocomposites’ stiffness and strain at break—by 20% and up to 90%, respectively—at the CNC concentration of 5 wt %, which is close to the critical percolation concentration. Since the CNC nanofiller simultaneously reduced LLDPE crystallinity, the reinforcement effect of CNCs was hampered. Therefore, the molding temperature was increased to 120 °C, and, in this way, the greatest increase of the Young’s modulus was achieved (by ~45%). Despite the enhanced compatibility of the AcAnh-modified CNCs with the LLDPE matrix, no additional effect on the mechanical properties of the nanocomposites was observed in comparison to the unmodified CNC.

Nanotechnology in food packaging materials: role and application of nanoparticles

“… 190 Different kind of polymers have been used as the matrixes. For example, A. Anžlovar et al (2018) 184 demonstrated that acetic anhydride-modified CNCs can act as reinforcement in linear low-density polyethylene (LLDPE) composites. The authors found an improvement in the compatibility between CNCs and the matrix, resulting in a 90% increase in the breaking strain of the composite.…”

Trends on the Cellulose-Based Textiles: Raw Materials and Technologies

“…Comparison microscopic image of; (B) bacterial nanocellulose (Li et al, 2017): Published by The Royal Society of Chemistry, (C) nanofibrillated cellulose: Reprinted (adapted) with permission from Saito et al (2007). Copyright (2007) American Chemical Society and, (D) nanocrystalline cellulose (Anžlovar et al, 2018). of temperature, agitation, and time (Clemons, 2016;Charreau et al, 2020).…”

Recent developments and prospective food-related applications of cellulose nanocrystals: a review

“…Various polymers have been employed as the matrixes. Anzlovar et al (Anzlovar et al 2018) reported that the acetic anhydridemodified CNCs could serve as a reinforcing agent for linear low-density poly(ethylene)…”