The fabrication of microcrystalline cellulose-nanoZnO hybrid composites and their application in rubber compounds

Rod-like Cellulose Regenerated by Bottom-Up Assembly in Natural Rubber Latex and Its Reinforcement

As a renewable biomass material, nano-cellulose has been investigated as a reinforcing filler in rubber composites but has seen little success because of its strong inclination towards aggregating. Here, a bottom-up self-assembly approach was proposed by regenerating cellulose crystals from a mixture of cellulose solution and natural rubber (NR) latex. Different co-coagulants of both cellulose solution and natural rubber latex were added to break the dissolution equilibrium and in-situ regenerate cellulose in the NR matrix. The SEM images showed that the sizes and morphologies of regenerated cellulose (RC) varied greatly with the addition of different co-coagulants. Only when a 5 wt% acetic acid aqueous solution was used, the RC particles showed an ideal rod-like structure with small sizes of about 100 nm in diameter and 1.0 μm in length. The tensile test showed that rod-like RC (RRC)-endowed NR vulcanizates with pronounced reinforcement had a drastic upturn in stress after stretching to 200% strain. The results of XRD and the Mullins effect showed that this drastic upturn in stress was mainly attributed to the formation of rigid RRC-RRC networks during stretching instead of the strain-induced crystallization of NR. This bottom-up approach provided a simple way to ensure the effective utilization of cellulosic materials in the rubber industry.

Assessing the suitability of self-healing rubber glove for safe handling of pesticides

Rubber gloves used for protection against chemicals or hazards are generally prone to tearing or leaking after repeated use, exposing the worker to potentially hazardous agents. Self-healing technology promises increased product durability and shelf life appears to be a feasible solution to address these issues. Herein, we aimed to fabricate a novel epoxidized natural rubber-based self-healable glove (SH glove) and investigate its suitability for handling pesticides safely. In this study, breakthrough time analysis and surface morphological observation were performed to determine the SH glove's ability to withstand dangerous chemicals. The chemical resistance performance of the fabricated SH glove was compared against four different types of commercial gloves at different temperatures. Using malathion as a model pesticide, the results showed that the SH glove presented chemical resistance ability comparable to those gloves made with nitrile and NR latex at room temperature and 37 °C. The self-healing test revealed that the SH glove could be self-healed and retained its chemical resistance ability close to its pre-cut value. Our findings suggested that the developed SH glove with proven chemical resistance capability could be a new suitable safety glove for effectively handling pesticides and reducing glove waste generation.

EMERGING ADVANCES IN RUBBER TECHNOLOGY BY THE SUITABLE APPLICATION OF SOL-GEL SCIENCE AND TECHNOLOGY

In recent years, the application of sol-gel science to industrial polymer research has offered advancements in rubber technology. The use of sol-gel–synthesized materials for the development of highly reinforced rubber composites is the most commonly adopted and popular method exercised by rubber scientists. This article comprehensively reviews the recent progress regarding preparation and properties of sol-gel–synthesized nanoparticles-based rubber composites. The pragmatic consequences of sol-gel–synthesized nanoparticles in rubber compounds are systematically described through rheological, mechanical, and thermal properties. Emphatic focus is given to understanding the reinforcement mechanism of rubber composites by the use of sol-gel–derived alkoxide silica as filler. The properties of rubber nanocomposites are usually dependent on the dispersion of sol-gel–synthesized nanoparticles into the rubber matrix. The results reviewed from prolific studies suggested that sol-gel science has tremendous potential to develop high performance rubber nanocomposites for future industrial application.

Van der Waals enhanced interfacial interaction in cellulose/zinc oxide nanocomposite coupled by graphitic carbon nitride

In-depth understanding of interfacial property is the key to guiding the synthesis of biomass composites with desired performance. However, the exploration is of great challenge due to limitations of experimental techniques in locating hydrogen, requiring large/good crystals and detecting a weak interaction like van der Waals (vdW). Herein, we experimentally and computationally investigated the composite cellulose/zinc oxide/g-C₃N₄. Hydrothermal synthesis afforded cellulose/ZnO, and then fabricated the ternary composite by adding g-C₃N₄ under ultrasonic condition. Three components are found to co-exist in the composite, and the ZnO nanoparticle is attaching to cellulose and coupling with g-C₃N₄. These experimental findings were corroborated by relativistic DFT calculations. The interfacial coupling is elaborated as contributions of dative bonds, hydrogen bonds and vdW interaction. The vdW is increased by a factor of 4.23 in the ZnO/g-C₃N₄ interface. This improves electron-hole separation and offers prospective application of the composite in photocatalysis, antibacteria and gas sensing.

Bio-synthesis of Barleria gibsoni leaf extract mediated zinc oxide nanoparticles and their formulation gel for wound therapy in nursing care of infants and children

Bio-synthesis of nano-metal oxide particles is gaining lot of significance and recommended as promising substitute not only physical methods but also chemical methods. Here in, we demonstrate the nano-zinc oxide (nano-ZnO) particles were successfully prepared by an eco-friendly process using plant Barleria gibsoni (B. gibsoni) aqueous leaf extract. The water leaf extract of B. gibsoni responsible for not only reducing source but also protective agent. The prepared nano-ZnO particles were studied by UV-Vis diffuse reflectance (UV-DRS), Photoluminescence (PL), Fourier transform (FT-IR) infrared spectroscopy, X-ray diffraction spectroscopy (X-RD), transmission electron microscopy (TEM), thermal stability was studied by thermogravimetric and differential thermal (TG-DTA) analysis and particle size by zeta sizer, dynamic light scattering (DLS). UV-DRS spectrum of nano-ZnO particles showed below at wave length 400 nm. FT-IR spectra showed that plant metabolites like polyphenols, flavonoids and amino acids etc., are act as reducing and protective agent. X-RD studies revealed the formed nano-ZnO particles have hexagonal (wurtzite) structure. TEM analysis confirmed the range of nanoparticles between 30 and 80 nm, which is supported by DLS analysis. The antibacterial property of synthesized nano-ZnO particles was tested with bacterial pathogens showed good results. The developed nano-ZnO gel act as an efficient and superior another tropical antimicrobial formulations for healing of burn infections. Moreover, the formulated nano-ZnO gel exhibited a remarkable wound healing potential in rats.