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Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared by Melt Processing.
Molecules. 2018 Jul 19; 23(7)M

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.

Authors+Show Affiliations

Department of Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. alojz.anzlovar@ki.si.Department of Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. matjaz.kunaver@ki.si.Department of Inorganic Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. andraz.krajnc@ki.si.Department of Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia. ema-zagar@ki.si.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

30029544

Citation

Anžlovar, Alojz, et al. "Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared By Melt Processing." Molecules (Basel, Switzerland), vol. 23, no. 7, 2018.
Anžlovar A, Kunaver M, Krajnc A, et al. Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared by Melt Processing. Molecules. 2018;23(7).
Anžlovar, A., Kunaver, M., Krajnc, A., & Žagar, E. (2018). Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared by Melt Processing. Molecules (Basel, Switzerland), 23(7). https://doi.org/10.3390/molecules23071782
Anžlovar A, et al. Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared By Melt Processing. Molecules. 2018 Jul 19;23(7) PubMed PMID: 30029544.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared by Melt Processing. AU - Anžlovar,Alojz, AU - Kunaver,Matjaž, AU - Krajnc,Andraž, AU - Žagar,Ema, Y1 - 2018/07/19/ PY - 2018/05/20/received PY - 2018/06/27/revised PY - 2018/07/12/accepted PY - 2018/7/22/entrez PY - 2018/7/22/pubmed PY - 2018/11/1/medline KW - cellulose nanocrystals KW - critical percolation concentration KW - esterification KW - linear low-density polyethylene KW - nanocomposites KW - surface modification JF - Molecules (Basel, Switzerland) JO - Molecules VL - 23 IS - 7 N2 - 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. SN - 1420-3049 UR - https://www.unboundmedicine.com/medline/citation/30029544/Nanocomposites_of_LLDPE_and_Surface_Modified_Cellulose_Nanocrystals_Prepared_by_Melt_Processing_ DB - PRIME DP - Unbound Medicine ER -