Cellulose Nanocrystals Aggregation Research Articles

Click-Chemistry-Enabled Functionalization of Cellulose Nanocrystals with Single-Stranded DNA for Directed Assembly.

Controlling the self-assembly of cellulose nanocrystals (CNCs) requires precise control over their surface chemistry for the directed assembly of advanced nanocomposites with tailored mechanical, thermal, and optical properties. In this work, in contrast to traditional chemistries, we conducted highly selective click-chemistry functionalization of cellulose nanocrystals with complementary DNA strands via a three-step hybridization-guided process. By grafting terminally functionalized oligonucleotides through copper-free click chemistry, we successfully facilitated the assembly of brushlike DNA-modified CNCs into bundled nanostructures with distinct chiral optical dichroism in thin films. The complexation behavior of grafted DNA chains during the evaporation-driven formation of ultrathin films demonstrates the potential for mediating chiral interactions between the DNA-branched nanocrystals and their assembly into chiral bundles. Furthermore, we discuss the future directions and challenges that include new avenues for the development of functional, responsive, and bioderived nanostructures capable of dynamic reconfiguration via selective complexation, further surface modification strategies, mitigating diverse CNC aggregation, and exploring environmental conditions for the CNC-DNA assembly.

Remediation of boron, lithium, and molybdenum by date pits modified with graphene oxide and cellulose nanocrystals: Mechanistic studies

This work aimed to modify date pits (DP), an agricultural waste product, with graphene oxide (GO) and cellulose nanocrystals (CNC) to develop a novel, environmentally friendly adsorbent referred to as GO-CNC@DP. A comprehensive study of the physicochemical characteristics of the prepared adsorbent in addition to the batch adsorption investigation on multiple pollutants (boron, lithium, and molybdenum) was studied. The results concluded that the endothermicity of the process due to the positive value of enthalpy change ΔH° that favors low levels of disorder and is spontaneous in nature due to the negative ΔG° values. At pH 2, the maximum adsorption capacities ranged between 15.5 mg/g and 82 mg/g for the three studied pollutants. The increase in adsorption capacity can be attributed to the alteration of the initial temperature from 25 °C to 45 °C. This phenomenon can be elucidated by considering the interactions such as surface complexation, electrostatic attraction, and ion exchange that occur between the pollutant and the adsorbent's surface. The excellent adsorption of boron, lithium, and molybdenum can be attributed to the attachment of GO to CNC on DP, which not only added more adsorption sites but also partially inhibited the aggregation of CNC. Therefore, GO-CNC@DP exhibited great results in the remediation of boron, lithium, and molybdenum from water in comparison to DP.

Ice recrystallization inhibition and acceleration by cellulose nanocrystals in the presence of anionic and neutral polymers

Understanding mixed stabilizers' ice recrystallization inhibition (IRI) effect is important for ice cream formulation. The IRI effect of cellulose nanocrystals (CNCs) was investigated in the presence of sodium alginate (SA), carboxymethyl cellulose (CMC), polyethylene glycol (PEG), and inulin. Adding low concentrations of SA (≤0.13%) and CMC (≤0.05%) enhanced the IRI effect of CNCs. The enhancement became less at higher concentrations of SA and CMC. Recrystallization was even accelerated with a further increase in concentration of SA (≥0.5%) or CMC (≥0.2%). PEG and inulin had little influence on the IRI effect of CNCs. Rheological analysis of polymer overlap concentration, particle size analysis of CNCs dispersion, and microscopical observation of ice crystals accretion suggested that the dual effects of excluded volume might explain the IRI effect of CNCs in the presence of polymers: (1) adding polymers resulted in the macromolecular crowding, reducing the available volume for CNCs and increasing their effective concentration to interact with ice crystals, and led to an enhanced IRI effect; (2) depletion interaction promoted the aggregation of CNCs and merging of ice crystals, resulting in less enhancement and recrystallization acceleration. Our findings advance our understanding of the IRI effect for mixed stabilizers and are critical to ice cream formulation.

The Influence of the Surface Chemistry of Cellulose Nanocrystals on Ethyl Lauroyl Arginate Foam Stability.

Guanidine-based surfactant ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNCs) form complexes of enhanced surface activity when compared to pure surfactants. The LAE-CNC mixtures show enhanced foaming properties. The dynamic thin-film balance technique (DTFB) was used to study the morphology, drainage and rupture of LAE-CNC thin liquid films under constant driving pressure. A total of three concentrations of surfactant and the corresponding mixtures of LAE with sulfated (sCNC) and carboxylated (cCNC) cellulose nanocrystals were studied. The sCNC and cCNC suspension with LAE formed thin films, with stability increasing with surfactant concentration and with complex rheological properties. In the presence of LAE, the aggregation of CNC was observed. While the sCNC aggregates were preferentially present in the film volume with a small fraction at the surface, the cCNC aggregates, due to their higher hydrophobicity, were preferentially located at film interfaces, forming compact layers. The presence of both types of aggregates decreased the stability of the thin liquid film compared to the one for the LAE solution with the same concentration. The addition of CNC to LAE was critical for foam formation, and foam stability was in qualitative agreement with the thin films' lifetimes. The foam volume increased with the LAE concentration. However, there was an optimum surfactant concentration to achieve stable foam. In particular, the very resistant foam was obtained with cCNC suspensions that formed the interfaces with a complex structure and rheology. On the other hand, at high LAE concentrations, the aggregates of CNC may exhibit antifoaming properties.

Incorporation of Polymer-Grafted Cellulose Nanocrystals into Latex-Based Pressure-Sensitive Adhesives.

While the improvement of water-based adhesives with renewable additives is important as industry shifts toward more sustainable practices, a complete understanding of how the compatibility between additives and polymers affects adhesive performance is currently lacking. To elucidate these links, cellulose nanocrystals (CNCs) were first functionalized via surface-initiated atom-transfer radical polymerization with the hydrophobic polymers poly(butyl acrylate) (PBA) and poly(methyl methacrylate) (PMMA) to facilitate their incorporation into latex-based pressure-sensitive adhesives (PSAs). Next, PBA latexes were synthesized using seeded semibatch emulsion polymerization with unmodified or polymer-grafted CNCs added in situ at a loading of 0.5 or 1 phm (parts per hundred parts of monomer). Viscosity and electron microscopy suggested that the polymer-grafted CNCs were incorporated inside or on the latex particles. PSAs containing any CNC type had one or more improved properties (compared to the no-CNC "base case"); CNCs with a low degree of polymerization (DP) grafts exhibited improved tack (up to 2.5-fold higher) and peel strength (up to 6-fold higher) relative to PSAs with unmodified CNCs. The best performing PSA contained the low DP PMMA-grafted CNCs, which is attributed to the higher glass transition temperature and the higher wettability of the PMMA grafts compared to PBA, and the more uniform dispersion of polymer-grafted CNCs throughout the PSA film. In contrast, PSAs containing CNCs with high DP grafts resulted in reduced tack and peel strength (compared to low DP grafts) due to enhanced CNC aggregation. Unfortunately, all PSAs containing polymer-grafted CNCs exhibited inferior shear strength relative to PSAs with unmodified CNCs (and comparable shear strength to the no-CNC "base case"). Collectively, these results provide guidelines for future optimization of more sustainable latex-based PSAs.

Nanocomposites Assembled via Electrostatic Interactions between Cellulose Nanocrystals and a Cationic Polymer.

On account of their high strength and stiffness and their renewable nature, cellulose nanocrystals (CNCs) are widely used as a reinforcing component in polymer nanocomposites. However, CNCs are prone to aggregation and this limits the attainable reinforcement. Here, we show that nanocomposites with a very high CNC content can be prepared by combining the cationic polymer poly[(2-(methacryloyloxy)ethyl) trimethylammonium chloride] (PMETAC) and negatively charged, carboxylated CNCs that are provided as a sodium salt (CNC-COONa). Free-standing films of the composites can be prepared by simple solvent casting from water. The appearance and polarized optical microscopy and electron microscopy images of these films suggest that CNC aggregation is absent, and this is supported by the very pronounced reinforcement observed. The incorporation of 33 wt % CNC-COONa into PMETAC allowed increasing the storage modulus of this already rather stiff, glassy amorphous matrix polymer from 1.5 ± 0.3 to 6.6 ± 0.1 GPa, while the maximum strength increased from 11 to 32 MPa. At this high CNC content, the reinforcement achieved in the PMETAC/CNC-COONa nanocomposite is much more pronounced than that observed for a reference nanocomposite made with unmodified CNCs (CNC-OH).

Major Factors Influencing the Size Distribution Analysis of Cellulose Nanocrystals Imaged in Transmission Electron Microscopy.

Size distributions of cellulose nanocrystals (CNCs), extracted from softwood pulp via strong sulfuric acid hydrolysis, exhibit large variability when analyzed from transmission electron microscopy (TEM) images. In this article, the causes of this variability are studied and discussed. In order to obtain results comparable with those reported, a reference material of CNCs (CNCD-1) was used to evaluate size distribution. CNC TEM specimens were prepared as-stained and dried with a rapid-flushing staining method or hydrated and embedded in vitreous ice with the plunge-freezing method. Several sets of bright-field TEM (BF-TEM), annular dark-field scanning TEM (ADF-STEM) and cryogenic-TEM (cryo-TEM) images were acquired for size distribution analysis to study the contributing factors. The rapid-flushing staining method was found to be the most effective for contrast enhancement of CNCs, not only revealing the helical structure of single CNCs but also resolving the laterally jointed CNCs. During TEM specimen preparation, CNCs were fractionated on TEM grids driven by the coffee-ring effect, as observed from contrast variation of CNCs with a stain-depth gradient. From the edge to the center of the TEM grids, the width of CNCs increases, while the aspect ratio (length to width) decreases. This fractionated dispersion of CNCs suggests that images taken near the center of a droplet would give a larger mean width. In addition to particle fractionation driven by the coffee-ring effect, the arrangement and orientation of CNC particles on the substrate significantly affect the size measurement when CNC aggregation cannot be resolved in images. The coexistence of asymmetric cross-section CNC particles introduces a large variation in size measurement, as TEM images of CNCs are mixed projections of the width and height of particles. As a demonstration of how this contributes to inflated size measurement, twisted CNC particles, rectangular cross-section particles and end-to-end jointed CNCs were revealed in reconstructed three-dimensional (3D) micrographs by electron tomography (ET).

Cellulose Nanocrystals Influence Polyamide 6 Crystal Structure, Spherulite Uniformity, and Mechanical Performance of Nanocomposite Films

Cellulose nanocrystals (CNCs) are an ideal reinforcing agent for polymer nanocomposites. CNCs can form hydrogen bonds with polyamide 6 (PA6); however, the direct effects of unmodified CNCs on PA6 morphology and crystal structure have not been fully elucidated. This work investigated the influence of CNCs on the mechanical performance and physicochemical properties of spin-coated CNC–PA6 films through quantitative analysis using techniques that probe multiple length scales. CNCs interacted with PA6 to induce the γ (chiral) allomorph over the α allomorph at low CNC loadings (≤1 wt %) and nucleated a high density of small uniform spherulites, leading to stiffer nanocomposites. Higher loadings caused CNC aggregation and crystalline, non-spherulitic features. Overall, we hypothesize that the reinforcement mechanism of CNCs in PA6 is dominated by morphological changes in the matrix, not percolation. Understanding CNC–polymer interactions and morphology (on films prepared without thermal processing or surface modification of CNCs) offers “design rules” for how to incorporate CNCs into nanocomposites for optimized material performance in various applications, for example, membranes, coatings, and packaging.

AFM characterization of cellulose nanocrystal height and width using internal calibration standards

A variety of models have been suggested for the cross-sectional shape and dimensions of cellulose nanocrystals (CNCs). Although many studies report measurements of CNC width (from transmission electron microscopy, TEM) and height (from atomic force microscopy, AFM), few have measured both cross-sectional dimensions for the same CNC sample and the same particles. Previous work has demonstrated that the TEM width is approximately twice the AFM height, a result that was explained by lateral aggregation of CNCs. Here we examine this question in more detail by measuring both CNC width and height by a single technique, AFM. The ability to measure both cross-sectional dimensions was facilitated by several factors: access to a fractionated CNC sample with few agglomerated particles, AFM imaging at low applied force with a small, nominal probe radius and in situ calibration of the AFM probe radius using co-deposited gold nanoparticles (AuNPs). Two sizes of AuNPs provided optimal calibration of the tip radius and allowed internal validation of the approach. The results show that the CNC width/height ratio covers a relatively wide range with a larger variation in width than height. The ratios indicate that approximately a third of the particles adsorb with their shorter cross-sectional side on the surface. A fraction of CNCs (28%) have an approximately symmetric cross-section whereas the remainder are asymmetric with one axis that is 2–3 times longer than the other. The results are consistent with a combination of laterally aggregated CNCs that cannot be resolved as individual particles and CNC particles that are comprised of multiple crystallites. This has important implications for applications in which the particle length/cross-section determines the CNC properties.

In-depth characterization of the aggregation state of cellulose nanocrystals through analysis of transmission electron microscopy images

Dispersion of cellulose nanocrystals (CNCs) is of utmost importance to guarantee their reliable application. Nevertheless, there is still no consensual method to characterize CNC aggregation. The hypothesis of this paper is that dispersion could be quantified through the classification of aggregates detected in transmission electron microscopy images. k-Means was used to classify image particulate elements of five CNC samples into groups according to their geometric features. Particles were classified into five groups according to their maximum Feret diameter, elongation, circularity and area. Two groups encompassed the most application-critical aggregates: one integrated aggregates of high complexity and low compactness while the other included elongated aggregates. In addition, the characterization of CNC dispersion after different levels of sonication was achieved by assessing the change in the number of elements belonging to each cluster after sonication. This approach could be used as a standard for the characterization of the aggregation state of CNCs.

Surface graft polymerization of lactic acid from the surface of cellulose nanocrystals and applications in chloroprene rubber film composites

Cellulose nanocrystals (CNCs) have been modified through surface graft polymerization of (l)-lactide for the purpose of improving dispersion and reducing aggregation of CNCs into chloroprene rubber (CR). Statistically designed experiments have been carried out to study the effects of polymerization conditions (temperature, and catalyst and monomer concentrations) on water contact angle, solvent dispersibility, and particle size distribution of the produced mCNCs. The effects of catalyst concentration and interaction of monomer-catalyst concentrations were found to be significant. Dry films produced from mCNCs exhibited surface hydrophobicity as evidenced by very high water contact angles (> 90°). In addition, mCNCs in powder form exhibited very good water/latex dispersibility. Blending of mCNCs with CR latex resulted in well-dispersed modified CNC/CR composites based on microscopy observations. The tensile properties of cast films produced from CNC/CR and mCNC/CR composites have been evaluated and it has been found that increasing the CNC and mCNC content increases tensile strength and modulus while maintaining elongation at break close to that of the unfilled CR. Composites containing 3 wt% of mCNCs exhibited the best properties with tensile strength and modulus improving by about 200% and 450%, respectively. These results are very promising and suggest that these mCNC/CR composites could find applications in the manufacturing of cut/fat resistant medical gloves, balloons, catheters, and other biomedical devices.

Investigation of the co-coagulation of natural rubber latex and cellulose nanocrystals aqueous dispersion

The quest to develop more eco-friendly and sustainable rubber products requires the use of lightweight fillers made from renewable feedstock and that have suitable mechanical and functional properties. Cellulose nanocrystals (CNCs) are among the most promising candidates for such applications due to their sustainability, abundance, high surface area, and excellent mechanical properties. To achieve a good reinforcing performance from CNCs in rubber, a high level of dispersion is needed. We have studied here the co-coagulation of natural rubber (NR) latex and CNC dispersions, which is possible because of the aqueous colloidal stability of both the CNC dispersion and NR latex. The coagulants used in this study are acetic acid, formic acid, and a combination of these acids with CaCl2 salt. While all the coagulants provided good coagulation, as seen by an excellent integration of the CNC into the rubber matrix, a combination of the acids with CaCl2 produced an undesirable CNC aggregation likely through the formation of CNC-cation-CNC bridges. Formic acid provides optimal co-coagulation and CNC dispersion as observed from scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) evaluations.

Improving dispersion stability of hydrochloric acid hydrolyzed cellulose nano-crystals

Cellulose nano-crystals (CNC) have attracted great interests as a novel nanostructured material in recent years, thanks to their excellent mechanical properties, high surface area and lightweight and biocompatibility etc. Due to its low charged group content, CNC prepared from the hydrochloric acid hydrolysis has poor dispersibility in water, which hinders its further applications. In this work, well-dispersed cellulose nano-crystals are successfully prepared using a two-step method, consisting of hydrochloric acid hydrolysis, followed by adsorption of hexadecyl trimethyl ammonium bromide (CTAB) onto CNC. Results show that CTAB at a low concentration (0.13–0.47 mM) provides effective steric barriers to minimize the CNC aggregation, which is supported by TEM images and particle size distribution of CNC. At high CTAB concentrations (>0.5 mM), CNC aggregation occurs, which is due to the “bridging” effect of CTAB.

Pickering Emulsions Electrostatically Stabilized by Cellulose Nanocrystals.

Cellulose Nanocrystals (CNC) are explored to stabilize oil/water emulsions for their ability to adsorb at the oil/water interface. In this work, the role of electrostatic forces in the CNC ability to stabilize oil/water emulsions is explored using canola oil/water and hexadecane/water as model systems. Canola oil/water and Hexadecane/ water (20/80, v/v) emulsions were stabilized with the addition of CNCs using ultrasonication. Emulsion droplet sizes range from 1 to 4 μm as measured by optical microscopy. It is found that CNC can stabilize oil/water emulsions regardless of their charge density. However, reducing the surface charge density, by adding salts and varying pH, can reduce the amount of CNC's required to form a stable emulsion. Just by adding 3 mM Na+ or 1 mM or less Ca+2 to a CNC suspension, the amount of CNC reduced by 30% to stabilized 2 mL of Canola oil. On the other hand, adding salt increases the emulsion volume. The addition of 100 mM Na+ or the reduction of pH below 2 leads to the aggregation of CNC; emulsions formed under these conditions showed gel-like behavior. This work shows the potential of nanocellulose crystal in stabilizing food and industrial emulsions. This is of interest for applications where biodegradability, biocompatibility, and food grade requirements are needed.

Fluorescent cellulose nanocrystals with responsiveness to solvent polarity and ionic strength

Fluorescent and stimuli-responsive cellulose nanocrystals (CNC) were prepared via covalent conjugation of a 1, 8-naphthalimide dye onto TEMPO-oxided CNC. The structural and morphological integrity of CNC were essentially not affected by the functionalizaiton, in spite of their relatively high dye content of 0.1 ± 0.01 mmol g−1. The dye-labeled CNC show much higher fluorescence sensitivity to solvent polarity and ion concentration compared to pure dye. The fluorescence emission of dye-labeled CNC is greatly enhanced when reducing solvent permittivity or increasing ionic strength. The magnified fluorescence responsiveness is attributed to the effect of aggregation-enhanced emission (AEE) based on the sensitive colloidal stability of CNC to medium conditions. Under high ionic strength and low solvent permittivity, the compressed double layers of CNC lead to space restriction and steric hindrance of dye groups, which limit the process of nonradiative transition. The aggregation of CNC triggered by the change of ion concentration was supported by dynamic light scattering (DLS) particle sizes and Zeta potential values. Owing to the special AEE effect, the fluorescent CNC are promising sensing nanomaterials for wide applications.

Water-In-Water Emulsion Gels Stabilized by Cellulose Nanocrystals.

Particle-stabilized water-in-water emulsions were prepared by mixing dextran and poly(ethylene oxide) (PEO) in water and adding cellulose nanocrystals (CNC). The CNC formed a layer at the surface of the dispersed droplets formed by the PEO-rich phase. Excess CNC partitioned to the continuous dextran phase. Aggregation of CNC at different rates was induced by adding NaCl between 10 and 100 mM. In the presence of more than 2 g/L CNC, fast aggregation led to the formation of an emulsion gel showing no signs of creaming. Confocal laser scanning microscopy showed that the emulgels were formed by a continuous network of CNC in which the randomly distributed droplets were embedded. The gel stiffness was measured with oscillatory shear rheology and found to increase strongly with increasing CNC concentration ( C). The dispersed droplets were elastically active and increased the gel stiffness at low C. However, up to C = 10 g/L, the yield stress was too small to inhibit the flow when the gels were tilted. At C < 2 g/L, creaming was observed until the network of connected droplets became sufficiently dense to be strong enough to resist buoyancy.

In Situ Cellulose Nanocrystal-Reinforced Glycerol-Based Biopolyester for Enhancing Poly(lactic acid) Biocomposites.

Biobased, elastomeric polymer poly(glycerol succinate-co-maleate) (PGSMA) was produced using a “green” synthesis with added cellulose nanocrystals (CNCs) to create a novel PGSMA–CNC material. PGSMA–CNC was synthesized with the aim of developing a new strategy for successfully dispersing CNCs within a poly(lactic acid) (PLA) matrix for optimal reinforcement of tensile strength and modulus while having the added benefit of the proven toughness enhancements of PLA/PGSMA blends. Optical microscopy and fractionation in tetrahydrofuran showed that CNCs agglomerated during PGSMA–CNC synthesis and remained in agglomerates during PLA/PGSMA–CNC reactive blending. Fourier transform infrared, differential scanning calorimetry, and dynamic mechanical analyses also showed that PGSMA–CNC inhibited the formation of PGSMA crosslinks and PLA-g-PGSMA during reactive blending. These two effects resulted in loss of impact strength and only a 4% increase in tensile modulus over PLA/PGSMA at the highest CNC content. Further work in preventing CNC aggregation could help improve mechanical properties of the final blend.

Effect of Cellulose Nanocrystals and Bacterial Cellulose on Disintegrability in Composting Conditions of Plasticized PHB Nanocomposites.

Poly(hydroxybutyrate) (PHB)-based films, reinforced with bacterial cellulose (BC) or cellulose nanocrystals (CNC) and plasticized using a molecular (tributyrin) or a polymeric plasticizer (poly(adipate diethylene)), were produced by solvent casting. Their morphological, thermal, wettability, and chemical properties were investigated. Furthermore, the effect of adding both plasticizers (20 wt % respect to the PHB content) and biobased selected nanofillers added at different contents (2 and 4 wt %) on disintegrability in composting conditions was studied. Results of contact angle measurements and calorimetric analysis validated the observed behavior during composting experiments, indicating how CNC aggregation, due to the hydrophilic nature of the filler, slows down the degradation rate but accelerates it in case of increasing content. In contrast, nanocomposites with BC presented an evolution in composting similar to neat PHB, possibly due to the lower hydrophilic character of this material. The addition of the two plasticizers contributed to a better dispersion of the nanoparticles by increasing the interaction between the cellulosic reinforcements and the matrix, whereas the increased crystallinity of the incubated samples in a second stage in composting provoked a reduction in the disintegration rate.

Estimation of aspect ratio of cellulose nanocrystals by viscosity measurement: influence of surface charge density and NaCl concentration

Cellulose nanocrystals (CNCs) with similar size and various surface charge densities were prepared by sulfuric acid hydrolysis and NaOH desulfation. The influence of surface charge density and NaCl concentration on the intrinsic viscosity of CNC suspensions and predicted aspect ratio were investigated by Ubbelohde viscometer. With decreased CNC surface charge density, the intrinsic viscosity initially decreased due to the electric double layers on the CNC surface and subsequently increased due to CNC aggregation. To screen electroviscous effect, NaCl was added into CNC suspensions. With increased NaCl concentration, the intrinsic viscosity of CNC suspensions first decreased and then increased. The aspect ratios of CNCs predicted by Batchelor equation from the minimum intrinsic viscosity were consistent with that measured by transmission electron microscopy. Suspensions of CNCs with higher surface charge density needed less NaCl to obtain minimum intrinsic viscosity. The NaCl content that should be added to the suspension to predict the actual physical aspect ratio of CNC can be estimated by Debye–Huckel theory, assuming that the Debye length is equal to the CNC diameter.

A Simple and Versatile Strategy To Improve the Mechanical Properties of Polymer Nanocomposites with Cellulose Nanocrystals

Cellulose nanocrystals (CNCs) are widely studied as reinforcing fillers for polymers. In many cases the mechanical properties of polymer/CNC nanocomposites do not match the theoretical predictions, arguably on account of CNC aggregation. This problem can be mitigated through the addition of a small amount of a judiciously selected polymeric dispersant that also serves as a binder among the CNCs. We show that the addition of 1–5% w/w poly(vinyl alcohol) (PVA) has a very significant impact on the mechanical properties of poly(ethylene oxide-co-epichlorohydrin)/CNC nanocomposites. Remarkable improvements of the stiffness and strength were observed at a PVA content as low as 1% w/w, and the extent of reinforcement increased up to a PVA content of 5% w/w, where Young’s modulus, storage modulus, and strength increased by up to 5-fold vis-a-vis the PVA-free nanocomposites. Similar effects were observed for CNC nanocomposites made with polyurethane or poly(methyl acrylate) matrices, demonstrating that the approac...