Packaging Composite Films Fabricated from Cellulose Pulp with Polyurethane and Curcumin by Using NMMO ionic Liquid Solvent

Cellulose pulp (CP), polyurethane (PU), and curcumin-based biocompatible composite films were prepared using a simple cost-effective method. These materials dissolved well in the ionic liquid solvent N-methylmorpholine N-oxide. Significant structural and microstructural changes were observed in CP upon the addition of PU. These changes were studied using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. The 5% and 10% gravimetric losses of the CP/PU/curcumin composite were found to be in the range 87.2–182.3 ºC and 166.7–249.8 ºC, respectively. The addition of PU significantly improved the thermal stability and water barrier properties of the composites. All the composites exhibited single Tg values in the range 147.4–154.2 ºC. The tensile strength of CP was measured to be 93.2 MPa, which dropped to 14.1 MPa for the 1:0.5 CP/PU composite and then steadily increased to 30.5 MPa with further addition of PU. The elongation at break of the composites decreased from 8.1 to 3.7% with the addition of PU. The addition of PU also improved the water vapor permeability (3.96 ×10–9 to 1.75 ×10–9 g m–1 s–1 Pa–1) and swelling ratio (285 to 202%) of the CP composite films. The CP/PU/curcumin composite exhibited good antioxidant activity and no cytotoxicity when tested on the HaCat cell line. The visual appearance and UV transmittance (86.2–32.9% at 600 nm) of the CP composite films were significantly altered by the incorporation of PU and curcumin. This study demonstrates that CP/PU/curcumin composites can be used for various packaging and biomedical applications.

Effect of ITO Content on Properties of Functional Graphene Coating on Cotton Fabric

In order to investigate the effect of indium tin oxide (ITO) on the performance of graphene functional coating on cotton fabric, different contents of ITO were added to the graphene coating system, and the effects of ITO content and curing time on various properties of graphene coating were studied. The results showed that the ITO particles adsorbed on the graphene sheets and filled the gaps between the graphene sheets, forming a dense conductive network, which could further improve the conductive performance of the functional coatings. When ITO content was 1.2%, the resistivity of the coating reached the lowest 1.8 Ω·cm, and the overall ultraviolet transmittance and reflectance were the lowest. With the increase of ITO content, the infrared reflectance will first decrease and then slowly increase, but the infrared reflectance is all below 0.5%. When the curing time reached 90 s, the resistivity and UV transmittance of cotton fabric coating decreased. With the extension of curing time, the coating on infrared reflectivity gradually increased, but the infrared reflectivity of the overall < 1%.

Minimal Erythema Dose Determination in Holstein Friesian Cattle

Cattle on pasture are continuously exposed to solar UV radiation, which has been associated with biological effects such as sunburn, photosensitization, squamous cell carcinoma, and cutaneous vitamin D3 production. The minimal erythema dose (MED) required to produce first-degree sunburn (erythema) is poorly researched in cattle. Since cattle are naturally covered with dense hair coats, the MED is influenced by the UV protection offered by the hair. The objective of this study was to determine the MED on intact-hair-covered (MED-H) and shaved white skin (MED-S) of Holstein Friesian cattle. Twenty-one Holstein Friesian cows and heifers were MED tested using a narrowband UV-B LED light (peak irradiance at 292 nm) on eight hair-covered and eight shaved areas over white skin previously unexposed to direct sunlight. Erythema was visually assessed after 24 h. The mean MED-H and MED-S were 5,595 and 329 J/m2, respectively. Heifers had a higher MED-H compared to cows, 7,600 and 4,969 J/m2, respectively. The mean UV transmittance of white cattle hair was 6.7%. MED-H was correlated with hair length (Spearman's rho = 0.76). A linear regression model showed that each millimeter of hair coat length increased the MED-H by 316 J/m2. In conclusion, this study provides a MED testing protocol for cattle and reports standardized values of MED for cattle on intact-hair-covered and shaved areas.

Green natural dye from Buddleja officinalis and its ultrasonic dyeing on cotton fabric

Purpose The purpose of this paper is to explore a new eco-friendly green textile dyeing. Natural plant Buddleja officinalis is traditionally used as yellow pigment addition in rice. It is worth developing its application and dyeing performance in cotton fabric. Design/methodology/approach Buddleja officinalis dried flower was extracted with ethanol aqueous. The extraction conditions including ethanol concentration, material to liquor ratio, extract time and temperature were optimized. Then cotton fabrics were dyed with Buddleja officinalis extraction under conventional and ultrasonic conditions. The effects of dyeing time, bath ratio, pH value of dyeing bath, dyeing temperature and mordants on K/S values were studied and the resulting color strength obtained by conventional and ultrasonic dyeing were compared. The ultraviolet (UV) transmittance of Buddleja officinalis dyed cotton fabric was also evaluated. Findings The color strength of the fabric dyed with Buddleja officinalis under ultrasonic conditions was higher than that under conventional conditions. Alum, Fe and Cu as simultaneous mordants improved the K/S value of the dyed cotton fabrics. Both washing fastness and rubbing fastness were fairly good in all Buddleja officinalis dyed cotton fabrics, washing fastness = 3–4 and rubbing fastness = 4. What’s more, the dyed cotton fabrics showed lower transmittance values as compared to undyed cotton fabrics and indicated potential UV protection capability. Practical implications Buddleja officinalis can be a new natural dye source for the ultrasonic dyeing of cotton fabric. Originality/value It is for the first time that Buddleja officinalis is used as a natural dye in cotton fabric dyeing with less water and the dyeing using ultrasound has been found to have an obvious improvement in the color strength and color-fastness.

Grass Waste Derived Cellulose Nanocrystals as Nanofiller in Polyvinyl Alcohol Composite Film for Packaging Application

Cellulose nanocrystals (CNCs) have shown remarkable application prospects due to their outstanding chemical and physical properties. In this research, cellulose nanocrystals were isolated from grass waste using alkali, bleaching and acid hydrolysis treatments and further used as nanofiller in polyvinyl alcohol (PVA) films. The valorisation of the grass waste, as an eco-friendly and sustainable low-cost precursor yields ~23.3% of CNCs. The morphology of the CNCs was observed under transmission electron microscopy and the influence of the grass waste derived CNCs (gw-CNCs) content on the optical transmittance, and water uptake and absorption capacity were investigated by varying the CNCs content in the PVA films. The results showed that the UV transmittance, and water uptake and absorption capacity of the composite films decreased with increasing of gw-CNCs content. The optimum gw-CNCs content for the composite film was determined in this study. The enhanced characteristics contributed to the UV shielding and water absorption properties implies the potential of the gw-CNCs to be used as potential nanofiller for packaging application.

Films Based on Mater-Bi® Compatibilized with Pine Resin Derivatives: Optical, Barrier, and Disintegration Properties

Mater-Bi® NF866 (MB) was blended with gum rosin and two pentaerythritol esters of gum rosin (labeled as LF and UT), as additives, to produce biobased and compostable films for food packaging or agricultural mulch films. The films were prepared by blending MB with 5, 10, and 15 wt.% of each additive. The obtained films were characterized by optical, colorimetric, wettability, and oxygen barrier properties. Moreover, the additives and the MB-based films were disintegrated under composting conditions and the effect of each additive on the biodegradation rate was studied. All films were homogeneous and optically transparent. The color of the films tended to yellow tones due to the addition of pine resin derivatives. All the formulated films presented a complete UV-transmittance blocking effect in the UVA and UVB region, and those with 5 wt.% of pine resin derivatives increased the MB hydrophobicity. Low amounts of resins tend to maintain the oxygen transmission rate (OTR) values of the neat MB, due to its good solubilizing and compatibilizing effects. The disintegration under composting conditions test revealed that gum rosin completely disintegrates in about 90 days, while UT degrades 80% and LF degrades 5%, over 180 days of incubation. As expected, the same tendency was obtained for the disintegration of the studied films, although Mater-Bi® reach 28% of disintegrability over the 180 days of the composting test.

Mussel-Inspired Approach to Constructing Dual Network Coated Layered Clay for Enhanced Barrier and Antibacterial Properties of Poly(vinyl alcohol) Nanocomposites

Inspired by complexation and mussel adhesion of catechol groups in tannic acid (TA), organophilic layered double hydroxides (LDHs@TA-Ti) were synthesized by forming a one-pot assembled TA-titanium (Ti) dual network coating on the surface of layered clay for the first time. LDHs@TA-Ti/poly(vinyl alcohol) (PVA) nanocomposites were prepared by the solution casting method. The results show that TA-Ti(IV) and TiO2 coordination compounds are simultaneously formed due to hydrolysis of titanium tetrachloride and complexation of TA in aqueous solution. Upon TA-Ti coatings onto the surface of LDHs, the antibacterial rate of LDHs@TA-Ti is up to 99.98%. Corresponding LDHs@TA-Ti/PVA nanocomposites also show outstanding antibacterial properties. Compared with pure PVA, LDHs@TA-Ti/PVA nanocomposites show a 40.9% increase in tensile strength, a 17.5% increase in elongation at break, a 35.9% decrease in oxygen permeability and a 26.0% decrease in water vapor permeability when adding 1 wt % LDHs@TA-Ti. UV transmittance (at 300 nm) of LDHs@TA-Ti/PVA nanocomposites decrease by 99.4% when the content of LDHs@TA-Ti reaches 3 wt %. These results indicate that PVA matrix incorporated with LDHs@TA-Ti could be used as a potential active packaging material to extend the shelf life of food products.

A framework for the use of artificial neural networks for water treatment: development and application

Artificial neural networks (ANNs) are increasingly being used in water treatment applications because of their ability to model complex systems. The present study proposed a framework to develop and validate ANNs for drinking water treatment and distribution system water quality applications. The framework was used to develop ANNs to identify the optimal ozone dose required for effective UV disinfection and to meet regulatory requirements for disinfection by-products (DBPs) in the distribution system. Treatment at a full-scale treatment plant was successfully modelled, with treated water UV transmittance as the output variable. ANNs could be used to identify operating setpoints that minimize operating costs for effective disinfection during drinking water treatment. However, because of the limited data available to train and validate the distribution system ANNs (i.e. n = 48; 15 years of quarterly measurements), these could not be used to reliably identify operating setpoints that also ensure compliance with DBP regulations.

Separation of Water/Oil Emulsions by an Electrospun Copolyamide Mat Covered with a 2D Ti3C2Tx MXene

Purpose: Copolyamide 6,10 (coPA) electrospun mats were covered with multilayered (ML) and single-layered (SL) MXene (Ti3C2Tx) as a membrane for the separation of water/vegetable oil emulsions. Methods: Prepared membranes were characterized by atomic force microscopy (AFM), profilometry, the contact angle measurements of various liquids in air, and the underwater contact angle of vegetable oil. The separation efficiency was evaluated by measuring the UV transmittance of stock solutions compared to the UV transmittance of the filtrate. Results: The MXene coating onto coPA mats led to changes in the permeability, hydrophilicity, and roughness of the membranes and enhanced the separation efficiency of the water/vegetable oil emulsions containing 10, 100, and 1000 ppm of sunflower vegetable oil. It was found that membranes were highly oleophobic (>124°) under water, unlike in air, where the membranes showed high oleophobicity (<5°). The separation efficiency of water/oil emulsions for both types of covered membranes reached over 99%, with a surface coverage of 3.2 mg/cm2 Ti3C2Tx (for ML-Ti3C2Tx) and 2.9 mg/cm2 (for SL-Ti3C2Tx). Conclusions: The separation efficiency was greater than 98% for membranes covered with 2.65 mg/cm2 of ML-Ti3C2Tx, whereas the separation efficiency for membranes containing 1.89 and 0.77 mg/cm2 was less than 90% for all studied emulsion concentrations.