In this work, a novel anti-corrosion water-based lubricant is prepared. Carboxymethyl cellulose and Uncaria Gambir Extract, all in powder form, were dispersed in water. Corrosion, stability, and tribology test with pin-on-disk reciprocating tribometer were studied. The newly obtained lubricants were designated as Uncaria Gambir (UG), i. e. UG0 (0% volume Uncaria Gambir extract in Carboxymethyl cellulose, UG1 (1% volume Uncaria Gambir extract in Carboxymethyl cellulose, and UG2 (2% volume Uncaria Gambir extract in Carboxymethyl cellulose). The addition of Uncaria Gambir Extract into Carboxymethyl cellulose solution delivered good stability, low corrosion rate, and stable friction coefficient. UG1 has the best stability (no sedimentation), corrosion, and tribological performance. After a one-hour friction test, UG2showed the best performance in terms of CoF, indicated by a 7.6% CoF reduction, compared to UG0. This finding indicates the potential of Uncaria Gambir Extract as an additive for an anticorrosive water-based lubricant for machining application.

There is an increasing demand for food packaging materials that are safe for the environment and human health. Pure polyvinyl alcohol (PVA) film is non-toxic and transparent but has poor UV-light shielding, thermal and moisture resistance, and antibacterial activity. Our previous work prepared and characterized a biofilm derived from PVA and edible Uncaria gambir extract (UG). The film has antibacterial properties and is anti-UV and flexible. However, UG is hydrophilic, making this film have low moisture absorption. To improve these properties, we trialed adding boric acid (BA) and UG into the PVA. This present study aims to characterize pure PVA film and blend films resulting from mixing PVA (10%), BA (0.5%), and UG (1%). It was found that the PVA/UG/BA film presented the best performance in terms of UV light absorption, tensile properties, thermal and moisture resistance, and antibacterial activity. This blend sample absorbs about 98% of the UV light at 400 nm wavelength without significantly sacrificing transparency. These findings indicate that UG and BA could be advantageous in the preparation of moisture and thermal-resistant UV shielding films with low toxicity and high antibacterial properties based on PVA. They were also found to be strong enough for food packaging applications.

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This research is aimed at studying the stability and tribology properties of the polyol ester oil- (POE-) based biolubricant mixed with various filler loadings from microparticle of TEMPO-oxidized bacterial cellulose (NDCt) as an additive and sorbitan monostearate (Span 60) as a surfactant. Morphology, rheology, and tribology tests were conducted. The addition of NDCt and Span 60 to pure POE as a base fluid showed elevated viscosity, lower value of coefficient friction (COF), and a remarkable decrease in the wear rate (WR). The presence of 0.6 wt% NDCt and 1.8 wt% Span 60 in POE (N2S4) decreased the COF value by 79% in comparison to POE. At room temperature, this N2S4 biolubricant sample showed a higher thermal conductivity by 4% and lower WR value by 49% compared to POE. This study introduced the preparation of the ecofriendly biolubricant filled with NDCt improving the tribology properties remarkably.

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