Naturally derived cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) are emerging nanomaterials that display high strength, high surface area, and tunable surface chemistry, allowing for controlled interactions with polymers, nanoparticles, small molecules, and biological materials. Industrial production of nanocelluloses is increasing rapidly with several companies already producing on the tons-per-day scale, intensifying the quest for viable products across many sectors. While the hydrophilicity of the nanocellulose interface has posed a challenge to the use of CNCs and CNFs as reinforcing agents in conventional plastics, it is a significant benefit for creating reinforced or structured hydrogel composites (or, when dried, aerogels) exhibiting both mechanical reinforcement and a host of other desirable properties. In this context, this Review describes the quickly growing field of hydrogels and aerogels incorporating nanocelluloses; over 200 references are summarized in comprehensive tables ...

http://pubs.acs.org/doi/pdf/10.1021/acs.chemmater.7b00531

Review of Hydrogels and Aerogels Containing Nanocellulose

This review addresses the recent developments of the, processing of cellulose nanocomposites, focusing on the most used techniques, including solution casting, melt-processing of thermoplastic cell ...

/pdf/review-of-the-recent-developments-in-cellulose-nanocomposite-6fx85zish5.pdf

Review of the recent developments in cellulose nanocomposite processing

In this review we introduce recent advances in the development of cellulose nanomaterials and the construction of high order structures by applying some principles of colloid and interface science. These efforts take advantage of natural assemblies in the form of fibers that nature constructs by a biogenetic bottom-up process that results in hierarchical systems encompassing a wide range of characteristic sizes. Following the reverse process, a top-down deconstruction, cellulose materials can be cleaved from fiber cell walls. The resulting nanocelluloses, mainly cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC, i.e., defect-free, rod-like crystalline residues after acid hydrolysis of fibers), have been the subject of recent interest. This originates from the appealing intrinsic properties of nanocelluloses: nanoscale dimensions, high surface area, morphology, low density, chirality and thermo-mechanical performance. Directing their assembly into multiphase structures is a quest that can yield useful outcomes in many revolutionary applications. As such, we discuss the use of non-specific forces to create thin films of nanocellulose at the air–solid interface for applications in nano-coatings, sensors, etc. Assemblies at the liquid–liquid and air–liquid interfaces will be highlighted as means to produce Pickering emulsions, foams and aerogels. Finally, the prospects of a wide range of hybrid materials and other systems that can be manufactured via self and directed assembly will be introduced in light of the unique properties of nanocelluloses.

Nanocellulose properties and applications in colloids and interfaces

From monomers to polymers from renewable resources: Recent advances

Recent advances in aerogels for environmental remediation applications: A review

Cellulose nanofi brils (CNF), also known as nanofi brillar cellulose (NFC), are an advanced biomaterial made mainly from renewable forest and agricultural resources that have demonstrated exceptional performance in composites. In addition, they have been utilized in barrier coatings, food, transparent fl exible fi lms and other applications. Research on CNF has advanced rapidly over the last decade and several of the fundamental questions about production and characterization of CNF have been addressed. An interesting shift in focus in the recent reported literature indicates increased efforts aimed at taking advantage of the unique properties of CNF. This includes its nanoscale dimensions, high surface area, unique morphology, low density and mechanical strength. In addition, CNF can be easily (chemically) modified and is readily available, renewable, and biodegradable. These facts are expected to materialize in a more widespread use of CNF. However, there is no clear indication of the most promising avenues for CNF deployment in commercial products. This review attempts to illustrate some exciting opportunities for CNF, specifi cally, in the development of aerogels, composites, bioactive materials and inorganic/organic hybrid materials.

http://www4.ncsu.edu/~ojrojas/PDF/2013_18.pdf

Cellulose Nanofibrils: From Strong Materials to Bioactive Surfaces

Organic aerogels based on two important and widely abundant renewable resources, soy proteins (SP) and nanofibrillar cellulose (NFC) are developed from precursor aqueous dispersions and a facile method conducive of channel- and defect-free systems after cooling and freeze-drying cycles that yielded apparent densities on the order of 0.1 g/cm3. NFC loading drives the internal morphology of the composite aerogels to transition from network- to fibrillar-like, with high density of interconnected cells. Composite aerogels with SP loadings as high as ca. 70 % display a compression modulus of 4.4 MPa very close to that obtained from reference, pure NFC aerogels. Thus, the high compression modulus of the composite system is not compromised as long as a relatively low amount of reinforcing NFC is present. The composite materials gain moisture (up to 5 %) in equilibrium with 50 % RH air, independent of SP content. Furthermore, their physical integrity is unchanged upon immersion in polar and non-polar solvents. Fast liquid sorption rates are observed in the case of composite aerogels in contact with hexane. In contrast, water sorption is modulated by the chemical composition of the aerogel, with an important contribution from swelling. The potential functionalities of the newly developed SP–NFC composite green materials can benefit from the reduced material cost and the chemical features brought about the amino acids present in SPs.

Soy protein–nanocellulose composite aerogels

Soy protein flour, isolate, and their derivatives were investigated to enhance the dry strength properties of paper. The soy systems were applied in aqueous suspensions consisting of lignin-free and recycled fibers to investigate their adsorption and interaction effects. Experiments using soy flour, soy protein isolate and its hydrolysates, cationized soy flour, and dual systems consisting of soy flour combined with cationic starch or chitosan were pursued. Improved paper strength was obtained when soy protein flour was utilized in combination with conventional treatments based on cationic polymers. For example, increases in ultimate tensile and compressive strength of lignin-free fiber paper of 23% and 10%, respectively, were measured when dual systems consisting of soy flour and cationic starch were applied relative to the fibers with no additive. In the case of lignin-containing recycled fibers, improvements of 52% and 56%, respectively, were obtained for a soy flour–chitosan dual system (compared to f...

Julio C. Arboleda

Papers

Cellulose Nanofibrils: From Strong Materials to Bioactive Surfaces

Soy protein–nanocellulose composite aerogels

Soy Protein-Based Polyelectrolyte Complexes as Biobased Wood Fiber Dry Strength Agents

Acid-generated soy protein hydrolysates and their interfacial behavior on model surfaces.