Characterization of Type-II Acetylated Cellulose Nanocrystals with Various Degree of Substitution and Its Compatibility in PLA Films

Dong, Feng; Yan, Meiling; Jin, Chunde; Li, Shujun

doi:10.3390/polym9080346

Cited by 45 publications

(20 citation statements)

References 39 publications

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“…The 13 C cross polarization-magic angle spinning (CP-MAS) NMR spectrum of the unmodified CNCs shows narrow signals corresponding to the cellulose C1–C6 carbons in the crystalline region, while two low intensity and broad signals belong to the C4′ and C6′ carbons in the amorphous region ( Figure 6 ) [ 38 ]. After CNC modification with AcAnh, two additional signals appeared at 170.8 ppm (C=O) and 20.8 ppm (CH 3 ), which indicated successful esterification of CNCs ( Figure 6 ).…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2018

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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.

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Section: Resultsmentioning

confidence: 99%

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

et al. 2018

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“…The modified microcrystalline cellulose could be added to PLA for various applications such as food packaging, liquid containers, plastic bags, disposable cups, etc. [ 59 , 60 , 61 , 62 ].…”

Section: Cellulose/pla Composite Materialsmentioning

confidence: 99%

A Review: Research Progress in Modification of Poly (Lactic Acid) by Lignin and Cellulose

et al. 2021

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With the depletion of petroleum energy, the possibility of prices of petroleum-based materials increasing, and increased environmental awareness, biodegradable materials as a kind of green alternative have attracted more and more research attention. In this context, poly (lactic acid) has shown a unique combination of properties such as nontoxicity, biodegradability, biocompatibility, and good workability. However, examples of its known drawbacks include poor tensile strength, low elongation at break, poor thermal properties, and low crystallization rate. Lignocellulosic materials such as lignin and cellulose have excellent biodegradability and mechanical properties. Compounding such biomass components with poly (lactic acid) is expected to prepare green composite materials with improved properties of poly (lactic acid). This paper is aimed at summarizing the research progress of modification of poly (lactic acid) with lignin and cellulose made in in recent years, with emphasis on effects of lignin and cellulose on mechanical properties, thermal stability and crystallinity on poly (lactic acid) composite materials. Development of poly (lactic acid) composite materials in this respect is forecasted.

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“…The cleaned NCC-SA was then dried under vacuum at 60 C. Synthesis of NCC-SA was verified with Fourier transform infrared (FTIR) measurements, as presented in the Supporting Information. The degree of substitution of the esterified NCC-SA was 44%, as inferred from FTIR measurements according to the description in Reference [28].…”

Section: Esterification Of Ncc With Stearoyl Chloridementioning

confidence: 99%

Comparison of nanocrystalline cellulose dispersion versus surface nucleation in poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) crystallization

Haham

Shen²,

Billington

et al. 2020

SPE Polymers

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Nanocrystalline cellulose (NCC), which is a known crystal nucleating agent, is utilized to improve poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) thermal properties. Since NCC aggregation in PHBV negatively affects composite properties and processability, NCC crystal nucleation effectiveness was examined at low concentrations (<1%) under isothermal and nonisothermal conditions. NCC was dispersed in PHBV solutions using a solvent exchange method and then cast into films. We found that NCC was an effective nucleating agent in amounts as low as 0.25%, resulting in an increase in PHBV crystallization rate by more than 50%. However, increasing to 1% NCC resulted in aggregation in PHBV, with the NCC becoming less effective compared to lower NCC concentrations. In an attempt to improve NCC dispersion, we added cellulose acetate (CA) or stearic acid (SA) to the casting solution, anticipating that CA or SA would preferentially adsorb on the NCC. With such pretreatment, dispersion was indeed improved but NCC became less effective as a PHBV nucleating agent. This work shows the advantage of using low NCC concentrations (<0.5%) for promoting PHBV crystallization, but the lack of improved nucleation upon addition of CA and SA supports the importance of NCC surface accessibility.

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Characterization of Type-II Acetylated Cellulose Nanocrystals with Various Degree of Substitution and Its Compatibility in PLA Films

Cited by 45 publications

References 39 publications

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

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

A Review: Research Progress in Modification of Poly (Lactic Acid) by Lignin and Cellulose

Comparison of nanocrystalline cellulose dispersion versus surface nucleation in poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) crystallization

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