Transparent tempo oxidized cellulose nanofibril (TOCNF) composites with increased toughness and thickness by lamination

Forti, Endrina S.; Moon, Robert J.; Schueneman, Gregory T.; Youngblood, Jeffrey P.

doi:10.1007/s10570-020-03107-8

Cited by 15 publications

(21 citation statements)

References 93 publications

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“…Figure 5 (b) shows results of UTS, where some variability on the results can be seen and it is attributed to the brittle behavior of TOCNF lms, where defects are randomly sized and distributed in the matrix. The presence of defects in the lms produces an ampli cation of the stress, leading to failure (Forti et al 2020). In the same manner discussed before, there is a marked increase in the mechanical properties related to the hydrolysis of the polymers, which could relate to the presence of a higher number of hydrogen bonds.…”

Section: C-tocnfs + Pva Nanocompositesmentioning

confidence: 99%

“…TEMPO-oxidized cellulose nano brils or TOCNFs are constituted by 2-3 nm wide brils with reduced adhesion between them, generating a transparent suspension with outstanding mechanical properties. TOCNF lms have been reported with an elastic modulus of up to 20GPa and UTS of up to 300 MPa while sustaining a more brittle behavior than mCNF (Saito et al 2007(Saito et al , 2009Fukuzumi et al 2009;Isogai et al 2011;Moon et al 2011;Fujisawa et al 2011;Benítez and Walther 2017;Forti et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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Mechanical enhancement of cellulose nanofibril (CNF) films through the addition of water-soluble polymers

Forti

Azrak

et al. 2021

Cellulose

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In this work, water-soluble polymers were screened through solution casting and polyvinyl alcohol (PVA) and poly(2-ethyl-2-oxazoline) (PEOX) were found as reinforcement agents for cellulose nano brils (CNFs) lms. Mechanical property increases of 99% in elastic modulus, 93% in the ultimate tensile strength (UTS) and 134% in the work of failure (WOF) were reported for TEMPO-oxidized cellulose nano brils (TOCNF) with 0.44 mmol/g carboxylate groups and 15 wt.% PVA. PEOX had a higher elastic modulus increase of 113%, yet lower UTS and WOF increases were found at 63% and 28%, respectively.Additionally, increases in UTS and elastic modulus were also seen in mechanically brillated CNF and TOCNFs with higher carboxylate contents (1.5 mmol/g). The toughening mechanism was attributed to the formation of strong hydrogen bonding between the CNFs and the hydrophilic polymers added. The presence of such mechanisms was indirectly con rmed by tensile testing, zeta potential and rheology.

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Section: C-tocnfs + Pva Nanocompositesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical enhancement of cellulose nanofibril (CNF) films through the addition of water-soluble polymers

Forti

Azrak

et al. 2021

Cellulose

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“…It was found that the weaker adhesion than the cohesion of the TOCNF led to crack deflection at the interface and was well explained by laminate theory. [ 107 ]…”

Section: Discrete Cnm Macrophase Compositesmentioning

confidence: 99%

Recent Developments in Cellulose Nanomaterial Composites

et al. 2020

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Cellulose nanomaterials (CNMs) are a class of materials that have recently garnered attention in fields as varied as structural materials, biomaterials, rheology modifiers, construction, paper enhancement, and others. As the principal structural reinforcement of biomass giving wood its mechanical properties, CNM is strong and stiff, but also nontoxic, biodegradable, and sustainable with a very large (Gton yr−1) source. Unfortunately, due to the relatively young nature of the field and inherent incompatibility of CNM with most man‐made materials in use today, research has tended to be more basic‐science oriented rather than commercially applicable, so there are few CNM‐enabled products on the market today. Herein, efforts are presented for preparing and forming cellulose nanomaterial nanocomposites. The focus is on recent efforts attempting to mitigate common impediments to practical commercialization but is also placed in context with traditional efforts. The work is presented in terms of the progress made, and still to be made, on solving the most pressing challenges—getting properties that are competitive with currently used materials, removing organic solvent, solving the inherent incompatibility between CNM and polymers of interest, and incorporation into commonly used industrial processing techniques.

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“…Laminates were tested in tension by cutting 40 mm x 4 mm rectangular shapes using a laser cutter. Fiberglass tabs were glued to the specimens using a fast cured epoxy according to the ASTM D3093 Standard Test Method for Tensile Properties Matrix Composites as described elsewhere (Forti et al 2020). Five specimens were tested on an MTS with a 1000 N load cell and a 0.5 mm/min rate.…”

Section: Laminates Characterizationmentioning

confidence: 99%

Optimized Mechanical And Impact Performance Of High Strength Tempo Oxidized Cellulose Nanofibril (TOCNF) - Epoxy Laminates

Forti

Betancourt-Jimenez

Schueneman

et al. 2021

Preprint

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In this work, TEMPO cellulose nanofibril (TOCNF) laminates were fabricated using a layup method. Two different TOCNF layers were tested, a neat TOCNF and a TOCNF with polyvinyl alcohol (PVA) strengthening aid with four different epoxy formulations as interlayers for the laminates. Flexural testing showed a correlation between the presence of stronger layers (TOCNF + PVA) in the laminate with a higher flexural strength, bending modulus, and work of failure. Different modes of fracture within the laminates occurred based on epoxy type. A stiffer epoxy generated a reduced mechanical response and substantial interlayer damage. On the other hand, a more ductile epoxy increased the WOF of the laminates, inducing a higher delamination at the interface. The addition of a silane coupling agent (APTES) resulted in a higher compatibility between the TOCNF and epoxy, generating an increased ultimate tensile strength (UTS) and a decreased energy to rupture associated with the reduction of crack digression mechanisms in the system. In general, laminates with stronger TOCNF layers (TOCNF + PVA) and increased adhesion (APTES), showed a flexural strength increase of 61%, a bending modulus increase of 80% and the same WOF when compared with the original laminates. Finally, impact testing of TOCNF materials was performed for the first time in literature, the specific energy to rupture of laminates was comparable to those achieved by acrylic and borosilicate glass, while maintaining a higher or similar specific strength to glass. Laminates showed good transparency and low haziness.

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Transparent tempo oxidized cellulose nanofibril (TOCNF) composites with increased toughness and thickness by lamination

Cited by 15 publications

References 93 publications

Mechanical enhancement of cellulose nanofibril (CNF) films through the addition of water-soluble polymers

Mechanical enhancement of cellulose nanofibril (CNF) films through the addition of water-soluble polymers

Recent Developments in Cellulose Nanomaterial Composites

Optimized Mechanical And Impact Performance Of High Strength Tempo Oxidized Cellulose Nanofibril (TOCNF) - Epoxy Laminates

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