Enhanced Stability, Superior Anti-Corrosive, and Tribological Performance of Al2O3 Water-based Nanofluid Lubricants with Tannic Acid and Carboxymethyl Cellulose over SDBS as Surfactant.

In this research work, the stability, tribological, and corrosion properties of a water-based Al2O3 nanofluid (0.5 wt%) formulated with tannin acid (TA) and carboxymethyl cellulose (CMC) as dispersants or surfactants were investigated. For comparative purposes, sodium dodecylbenzene sulfonate (SDBS) was also incorporated. The stability of the nanofluid was assessed through zeta potential measurements and photo-capturing, revealing the effectiveness of TA and CMC in preventing nanoparticle agglomeration. Tribological properties were examined using a pin-on-disk apparatus, highlighting the tribofilm of Al2O3 that enhanced lubricating properties of the nanofluid by the SEM, resulting in reduced friction and wear of the contacting surfaces. Sample with the addition of both TA and CMC exhibited the best tribological performance, with a ~ 20% reduction in the friction coefficient and a 59% improvement in wear rate compared to neat nanofluid without TA and CMC. Additionally, the corrosion resistance of the nanofluids were evaluated via weight loss and electrochemical impedance spectroscopy. The nanofluid sample containing both TA and CMC exhibited the lowest corrosion rate, with 97.6% improvement compared to sample without them. This study provides valuable insights into the potential applications of TA and CMC-based Al2O3 nanofluids as effective and environmentally friendly solutions for coolant or lubrication in cutting processes.

Erythrosine-Dialdehyde Cellulose Nanocrystal Coatings for Antibacterial Paper Packaging.

Though paper is an environmentally friendly alternative to plastic as a packaging material, it lacks antibacterial properties, and some papers have a low resistance to oil or water. In this study, a multifunctional paper-coating material was developed to reduce the use of plastic packaging and enhance paper performance. Natural cellulose nanocrystals (CNCs) with excellent properties were used as the base material for the coating. The CNCs were functionalized into dialdehyde CNCs (DACNCs) through periodate oxidation. The DACNCs were subsequently complexed using erythrosine as a photosensitizer to form an erythrosine-CNC composite (Ery-DACNCs) with photodynamic inactivation. The Ery-DACNCs achieved inactivations above 90% after 30 min of green light irradiation and above 85% after 60 min of white light irradiation (to simulate real-world lighting conditions), indicating photodynamic inactivation effects. The optimal parameters for a layer-by-layer dip coating of kraft paper with Ery-DACNCs were 4.5-wt% Ery-DACNCs and 15 coating layers. Compared to non-coated kraft paper and polyethylene-coated paper, the Ery-DACNC-coated paper exhibited enhanced mechanical properties (an increase of 28% in bursting strength). More than 90% of the bacteria were inactivated after 40 min of green light irradiation, and more than 80% were inactivated after 60 min of white light irradiation.

Rice straw-derived chitosan-enhanced plasticizers as biologically and environmentally friendly alternatives for sustainable materials.

Plasticizers like Bis(2-ethylhexyl)phthalate (DEHP) are commonly used to enhance plastic properties but pose environmental and health risks. This study successfully derived plasticizers X and Y from rice straws, demonstrating efficacy in chitosan polymer coatings. Chitosan-based polymers exhibit exceptional hardness, with a value of 300 MPa, due to their enriched structure and robust chitosan bonding. This surpasses the hardness of DEHP. Zebrafish exposure over 5 days revealed that X and Y had no significant behavioral impact, while DEHP caused noticeable toxic effects. Maternal DEHP exposure reduced placental cell growth, unlike X and Y, which had no adverse effects on uterine differentiation or placenta formation, suggesting their safety in human pregnancy. The successful development of X and Y represents a crucial step towards greener plasticizers, addressing environmental concerns and promoting safer alternatives in various industries.

Effect of post-heat treatment on the UV transmittance, hydrophobicity, and tensile properties of PVA/Uncaria gambir extract blend films.

The physical and mechanical properties of biopolymers can be improved by heating technologies. In this research, we improved the properties of Polyvinyl alcohol (PVA)/Uncaria gambir extract (UGE) blend films by post-heating method. After post-heating, the blend film exhibited higher resistance to UV light and improved contact angle performance, while water vapor permeability and moisture absorption decreased. The tensile strength and toughness of the PVA/UGE blend film with a post-heating duration of 40 min were 68.8 MPa and 57.7 MPa, respectively, an increase of 131 % and 127 %, compared to films without post-heating. This facile and cost-effective fabrication method, with environmentally friendly properties, can be applied to biodegradable PVA/UGE blend films to achieve desired properties for optical devices or food packaging materials.

A Novel Highly Conductive, Transparent, and Strong Pure-Cellulose Film from TEMPO-Oxidized Bacterial Cellulose by Increasing Sonication Power.

Developing a conductive cellulose film without any metal compounds remains challenging, though in great demand. However, cellulose film prepared from bacterial cellulose (BC) powder without any metal compounds has poor tensile, physical, and electrical properties, thus limiting its application. Herein, this study aims to prepare and characterize an all-cellulose film from 2,2,6,6-Tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidized bacterial cellulose (TOBC) powders without adding metal compounds and treated by ultrasonication. TOBC powders are sonicated with various powers of 250, 500, and 750 W for 20 min without any other substance. It was proved that increasing the ultrasonication power level resulted in a significant improvement in the properties of the film. The ultrasonication of 750 W increased tensile strength by 85%, toughness by 308%, light transmittance by 542%, and electrical conductivity by 174% compared to the nonsonicated film. A light-emitting diode connected to a power source through this sonicated film was much brighter than that connected via a nonsonicated film. For the first time, this study reports the preparation of electrically conductive, transparent, strong, and bendable pure TOBC films by increasing ultrasonic power for environmentally friendly electronic devices application.

Highly antimicrobial and strong cellulose-based biocomposite film prepared with bacterial cellulose powders, Uncaria gambir, and ultrasonication treatment.

This work characterized bacterial cellulose (BC)/Uncaria gambir (G) biocomposite film prepared with ultrasonication treatment. Films were prepared from BC powder suspensions in distilled water without and with various loadings (0.05 g, 0.1 g, 0.2 g, 2 g) of G powder then treated using an ultrasonic probe at 1000 W for one hour. The results revealed that the ultrasonication treatment of the suspension greatly increased tensile strength (TS), elongation at break (EB), and toughness (TN) of a BC film by 3097%, 644%, and 32,600%, respectively, compared to non-sonicated BC film. After adding 0.05 g G into the sonicated BC powder suspension, TS, EB, and TN of the biocomposite film were improved to 105.6 MPa, 14.3%, and 8.7 MJ/m3, respectively. The addition of the G increased in antimicrobial activity of the film. This study indicates that biocomposite film is potentially useful for nanopaper production with good antimicrobial and high tensile properties.