This study is aimed to explore the properties of cellulose nanocrystals (CNC)/polyvinyl alcohol (PVA) composite films with and without 1,2,3,4‐butane tetracarboxylic acid (BTCA), a nontoxic crosslinker. CNC and CNC‐PVA nanocomposite films are prepared using solution‐casting technique. Differential scanning calorimetry (DSC) analyses show that crosslinking increased the glass transition temperature but reduced the melting temperature and crystallinity. Furthermore, high CNC concentrations in the PVA matrix interfere with PVA crystallinity, whereas in specific ratio between CNC and PVA, two different crystalline structures are observed within the PVA matrix. Film surfaces and fracture topographies characterized using scanning electron microscope indicate that at certain CNC‐PVA ratios, micron‐sized needle‐like crystals have formed. These crystalline structures correlate with the remarkable improvement in mechanical properties of the CNC‐PVA nanocomposite films, that is, enhanced tensile strain and toughness to 570% and 202 MJ m−3, respectively, as compared to pristine PVA. BTCA enhances the tensile strain, ultimate tensile stress, toughness, and modulus of CNC films compared to pristine CNC films. Water absorption of crosslinked CNC and CNC‐PVA nanocomposite films is significantly reduced, while film transparency is significantly improved as a function of PVA and crosslinker content. The presented results indicate that CNC‐PVA nanocomposite films may find applications in packaging, and though materials applications.

The demonstration of reliable and stable white light-emitting diodes (LEDs) is one of the main technological challenges of the LED industry. This is usually accomplished by incorporation of light-emitting rare-earth elements (REEs) compounds within an external polymeric coating of a blue LED allowing the generation of white light. However, due to both environmental and cost issues, the development of low-cost REE-free coatings, which exhibit competitive performance compared to conventional white LED is of great importance. In this work, the formation of an REE-free white LED coating is demonstrated. This biocomposite material, composed of biological (crystalline nanocellulose and porcine gastric mucin) and organic (light-emitting dyes) compounds, exhibits excellent optical and mechanical properties as well as resistance to heat, humidity, and UV radiation. The coating is further used to demonstrate a working white LED by incorporating it within a commercial blue LED.

Cellulose nanocrystals (CNC) are well-suited to the preparation of biocomposite films and packaging material due to its abundance, renewability, biodegradability, and favorable film-forming capacity. In this study, different CNC and corn zein (CZ) composite films were prepared by adding CZ to the CNC suspension prior to drying, in order to change internal structure of resulting films. Films were developed to examine their performance as an alternative water vapor and oxygen-barrier for flexible packaging industry. Water vapor permeability (WVP) and oxygen transmission rate (OTR) of the biocomposite films decreased significantly in a specific ratio between CNC and CZ combined with 1,2,3,4-butane tetracarboxylic acid (BTCA), a nontoxic cross linker. In addition to the improved barrier properties, the incorporation of CZ benefitted the flexibility and thermal stability of the CNC/CZ composite films. The toughness increased by 358%, and Young’s modulus decreased by 32% compared with the pristine CNC film. The maximum degradation temperature increased by 26 °C, compared with that of CNC film. These results can be attributed to the incorporation of a hydrophobic protein into the matrix creating hydrophobic interactions among the biocomposite components. SEM and AFM analysis indicated that CZ could significantly affect the CNC arrangement, and the film surface topography, due to the mechanical bundling and physical adsorption effect of CZ to CNC. The presented results indicate that CNC/CZ biocomposite films may find applications in packaging, and in multi-functionalization materials.

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In article number https://doi.org/10.1002/adfm.201706967, Roey Elnathan, Oded Shoseyov, Shachar Richter, and co‐workers demonstrate the formation of white light‐emitting stable biocomposite material. This film, composed of biological (crystalline nanocellulose and mucin protein) and organic (light‐emitting dyes) compounds, exhibits excellent optical and mechanical properties, and resistance to heat, humidity, and UV radiation. It is further used to demonstrate a working white LED by incorporating it into a commercial blue LED.