Cellulose nanocrystals (CNC) were mixed with either cellulose nanofibril (CNF) or carboxymethylcellulose (CMC) in variable proportions (0/100, 20/80, 40/60, 50/50, 60/40, 80/20 and 100/0) to obtain cast films with acceptable barrier and mechanical properties as replacements for food packaging plastics. Both CNF and CMC improved tensile strength, elongation, UV opacity, air resistance, hydrophobicity (WCA-water contact angle), water vapor transmission rate (WVTR) and oxygen impermeability in pure CNC. WVTR and oxygen permeability were strongly dependent on relative humidity (RH). Interestingly, the greatest effect on WVTR was observed at RH = 90% in films containing CMC in proportions above 60%. CMC- and CNF-containing films had oxygen impermeability up to an RH level of 80% and 60%, respectively. The previous effects were confirmed by food packaging simulation tests, where CMC-containing films proved the best performers. The composite films studied were biodegradable-which constitutes a major environmental related advantage-to an extent proportional to their content in CMC or CNF.

Topological variety of robust networks from nanofibrils enables the formation of strong and tough particle constructs ubiquitously.

Polydisperse smooth and spherical biocolloidal particles were suspended in aqueous media and allowed to consolidate via evaporation-induced self-assembly (EISA). The stratification of the particles at the solid-air interface was markedly influenced but not monotonically, by the drying rate. Cross section imaging via electron microscopy indicated a structured coating morphology that was distinctive from that obtained by using mineral particles with mono- or bimodal distribution. Segregation patterns were found to derive from the interplay of particle diffusion, inter-particle forces and settling dynamics. Supporting our experimental findings, computer simulations showed an optimal drying rate for achieving maximum segregation. Overall, stratified coatings comprising nano and microparticles derived from lignin are expected to open opportunities for multifunctional structures that can be designed and predicted on the basis of experimental Peclet numbers and computational order.

Cellulose nanocrystals (CNCs) were mixed with various additives to obtain films with good barrier and mechanical properties as replacements for petroleum-based plastics. The influence of different doses of additives including sorbitol (Sor), glycerol (Gly), maltitol (Mal), xylitol (Xyl), mannitol (Man), gellan gum (Gg), and ethylene glycol (Eg) on the resulting films was examined. Both the type of additive and its amount were found to affect film morphology, barrier, optical and mechanical properties. Most of the additives showed good results at low doses. All additives, except Eg and Man, improved film elongation; also, they increased tensile strength and decreased air and water permeance. The films containing Sor, Xyl, and Mal exhibited the highest barrier properties, providing films with totally resistance to oxygen under 60% of relative humidity conditions. Interestingly, those films containing additives were more easily biodegraded than the control film.