Rising environmental concerns and depletion of petro-chemical resources has resulted in an increased interest in biorenewable polymer-based environmentally friendly materials. Among biorenewable polymers, lignin is the second most abundant and fascinating natural polymer next to cellulose. Lignin is one of the three major components found in the cell walls of natural lignocellulosic materials. Lignin is widely available as a major byproduct of a number of industries involved in retrieving the polysaccharide components of plants for industrial applications, such as in paper making, ethanol production from biomass, etc. The impressive properties of lignin, such as its high abundance, low weight, environmentally friendliness and its antioxidant, antimicrobial, and biodegradable nature, along with its CO2 neutrality and reinforcing capability, make it an ideal candidate for the development of novel polymer composite materials. Considerable efforts are now being made to effectively utilize waste lignin as one ...

Progress in Green Polymer Composites from Lignin for Multifunctional Applications: A Review

Unconventional methods in cellulose functionalization

Review: Raw Natural Fiber–Based Polymer Composites

Metallic-based micro and nano-structured materials are incorporated into food contact polymers to enhance mechanical and barrier properties, and to prevent the photodegradation of plastics. Additionally heavy metals are effective antimicrobials in the form of salts, oxides, and colloids, complexes such as silver zeolites, or as elemental nanoparticles. They are incorporated for food preservation purposes and to decontaminate surfaces in industrial environments. Other relevant properties in active food packaging, such as the capability for ethylene oxidation or oxygen scavenging, can be used to extend food shelf-life. Silver based nano-engineered materials are currently the most commonly used in commodities due to their antimicrobial capacity. Copper, zinc and titanium nanostructures are also showing promise in food safety and technology. The antimicrobial properties of zinc oxide at the nanoscale will provide affordable and safe innovative strategies. Copper has been shown to be an efficient sensor for humidity, and titanium oxide has resistance to abrasion and UV-blocking performance. The migration of cations from the polymer matrices is the key point to determine their antimicrobial effectiveness; however, this cation migration may affect legal status of the polymer as a food-contact material.

Metallic-based micro and nanocomposites in food contact materials and active food packaging

Isolation and structural characterization of cellulose nanocrystals extracted from garlic straw residues

Photocatalytic degradation of Rhodamine B dye using ZnO–SnO2 electrospun ceramic nanofibers

A study of the carboxymethylation of wood pulp cellulose and cotton linters cellulose in different organic media, namely, ethanol, acetone, and ethanol-acetone mixtures, is performed. Previously, the ethanol-acetone 1 : 1 (w/w) mixture used as reaction medium was found to give a higher degree of substitution (DS) than the pure solvents separately. In the present work, the kinetic investigation of cellulose carboxymethylation was carried out in ethanol-acetone 3 : 7 (w/w) mixture, as well as in acetone as reaction media, and the same synergistic effect of the solvents mixture was observed. The data suggested a pseudo-first-order kinetic behavior satisfactorily described by the following equation: ln(1.11 − DS) = −kt. The two reaction steps observed are related to the transformations of less ordered regions with higher reaction rate and more ordered regions with smaller reaction rates, respectively. A possible explanation for this behaviour is given, taking into account the different structural changes of cellulose crystallinity and accessibility produced by ethanol-acetone 3 : 7 (w/w) mixture, ethanol, and acetone, as revealed by X-ray diffraction and calorimetry determinations. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 481–486, 1998

Carboxymethylcellulose synthesis in organic media containing ethanol and/or acetone

Zinc oxide (ZnO) nanostructures are among the most interesting nanomaterials due to their remarkable performance in optics, electronics, semiconducting materials, and photocatalysis. Recent literat...

Zinc Oxide Nanocrystals Grown on Cellulose Acetate Butyrate Nanofiber Mats and Their Potential Photocatalytic Activity for Dye Degradation

Heterogeneous acetylation to a low extent of bleached and unbleached commercial kraft pulps was performed with acetic anhydride without solvents and in the presence of sulfuric acid catalyst. The process was conducted in an effort to change the polarity of studied kraft pulps and to improve their compatibility with synthetic polymers without changing their fibrous structure. It was observed that the fiber morphology does not change up to a reaction time of 3 h for both investigated materials. The hydrophilic character of the bleached pulp was decreased by acetylation to a low extent, while the unbleached material showed an initial increase of water retention capacity. At higher degrees of modification, both pulps exhibited similar hydrophilic properties. For both materials, an initial slightly increased susceptibility to enzymatic attack with cellulase from Trichoderma reesei was observed, however the acetylated bleached cellulose fibers were more susceptible to enzymatic attack than those of the unbleached material.

Liliana Olaru

Papers

Photocatalytic degradation of Rhodamine B dye using ZnO–SnO2 electrospun ceramic nanofibers

Carboxymethylcellulose synthesis in organic media containing ethanol and/or acetone

Zinc Oxide Nanocrystals Grown on Cellulose Acetate Butyrate Nanofiber Mats and Their Potential Photocatalytic Activity for Dye Degradation

Surface modified cellulose obtained by acetylation without solvents of bleached and unbleached kraft pulps

On the hydrolysis of cellulose acetate in toluene/acetic acid/water system.