Synergistic effect of graphene oxide/montmorillonite-sodium carboxymethycellulose ternary mimic-nacre nanocomposites prepared via a facile evaporation and hot- pressing technique

Recent advances in carboxymethyl cellulose-based active and intelligent packaging materials: A comprehensive review

Researchers have concentrated on innovative approaches to increase the shelf life of perishable food products and monitor their quality during storage and transportation as consumer demand for safe, environmentally friendly, and effective packaging develops. This comprehensive review aims to provide an overview of recent developments in carboxymethyl cellulose (CMC) chemical synthesis and its applications in active and intelligent packaging materials. It explores various methods for modifying cellulose to produce CMC and highlights the unique properties that make it suitable for addressing packaging industry challenges. The integration of CMC into active packaging systems, which helps reduce food waste and enhance food preservation, is discussed in depth. Furthermore, the integration of CMC in smart sensors and indicators for real-time monitoring and quality assurance in intelligent packaging is examined. The chemical synthesis of CMC and strategies to optimise its properties were studied, and the review concluded by examining the challenges and prospects of CMC-based packaging in the industry. This review is intended to serve as a valuable resource for researchers, industry professionals, and policymakers interested in the evolving landscape of CMC and its role in shaping the future of packaging materials.

Comprehensive Review of Recent Research Advances on Flame-Retardant Coatings for Building Materials: Chemical Ingredients, Micromorphology, and Processing Techniques

Developing fire-retardant building materials is vital in reducing fire loss. The design and preparation of novel fire-retardant coatings merely require the adhesion of flame retardants with high fire-retardant characteristics on the surface, which is significantly more economical than adding excessive amounts of flame retardants into bulk building materials. Meanwhile, fire-retardant coating has excellent performance because it can block the self-sustaining mechanisms of heat and mass transfer over combustion interfaces. In recent years, research of fire-retardant coatings for building materials has been subject to rapid development, and a variety of novel environmentally benign fire-retardant coatings have been reported. Nonetheless, as the surface characteristics of various flammable building materials are contrastively different, selecting chemical ingredients and controlling the physical morphology of fire-retardant coatings for specific building materials is rather complicated. Thus, it is urgent to review the ideas and preparation methods for new fire-retardant coatings. This paper summarizes the latest research progress of fire-retardant building materials, focusing on the compositions and performances of fire-retardant coatings, as well as the principles of their bottom-up design and preparation methods on the surface of building materials.

High efficiency and selective removal of Cu(Ⅱ) via regulating the pore size of graphene oxide/montmorillonite composite aerogel

In this study, based on the differences in the coordination configurations of various alkaline earth metal ions (Ca(Ⅱ) and Sr(Ⅱ)) and sodium alginate (SA), the aerogel is functionalized with controllable slit-shaped pores structure, contributing by nanosheet stacking impact of graphene oxide (GO) and montmorillonite (MMT), which is able to selectively remove plane hydrate copper ions in complex wastewater systems. Sr-G/M is endowed with denser slit-shaped pores and could achieve more efficient selective removal of Cu(Ⅱ), together with a best removal efficiency of 97.1%, proving by systematic adsorption tests. The selectivity tests show that Sr-G/M exhibits preferential adsorption for Cu(Ⅱ) with a distribution coefficient of 41.85 L g^-1. Furthermore, Sr-G/M has excellent regeneration performance to be 86.4% after 8 recycles. Considering its cost-effectiveness, eco-friendliness, easy preparation and efficient selective removal performance, Sr-G/M holds great promise in selective removal of Cu(Ⅱ) from complex wastewater systems.

Layered Clay–Graphene Oxide Nanohybrids for the Reinforcement and Fire-Retardant Properties of Polyurea Matrix

Nanostructures are more and more evolved through extensive research on their functionalities; thus, the aim of this study was to obtain layered clay–graphene oxide nanohybrids with application as reinforcing agents in polyurea nanocomposites with enhanced thermal–mechanical and fire-retardant properties. Montmorillonite (MMT) was combined with graphene oxide (GO) and amine functionalized graphene oxide (GOD) through a new cation exchange method; the complex nanostructures were analyzed through FTIR and XPS to assess ionic interactions between clay layers and GO sheets by C1s deconvolution and specific C sp3, respective/ly, C-O secondary peaks appearance. The thermal decomposition of nanohybrids showed a great influence of MMT layers in TGA, while the XRD patterns highlighted mutual MMT and GO sheets crystalline-structure disruption by the d (002) shift 2θ = 6.29° to lower values. Furthermore, the nanohybrids were embedded in the polyurea matrix, and the thermo-mechanical analysis gave information about the stiffness of MMT–GO nanocomposites, while GOD insertion within the MMT layers resulted in a 30 °C improvement in the Tg of hard domains, as shown in the DSC study. The micro CT analysis show good dispersion of inorganic structures within the polyurea, while the SEM fracture images revealed smooth surfaces. Cone calorimetry was used to evaluate fire-retardant properties through limiting the oxygen index, and MMT–GOD based nanocomposites showed a 35.4% value.

Coordination-driven interfacial cross-linked graphene oxide-alginate nacre mesh with underwater superoleophobicity for oil-water separation

Inspired by the seashell nacre and seaweed, a novel GO-Ca²⁺-SA nacre-inspired hybrid mesh was prepared via an interfacial layer-by-layer self-assembly and cross-linking, using graphene oxide (GO) and sodium alginate (SA) as the building blocks and calcium chloride as the coordination agent, respectively. Hybrid mesh was characterized by FTIR, XPS, XRD, SEM and contact angel instrument, showing superhydrophilic and underwater superoleophobic property and low oil adhesion, due to its wrinkle and rough surface, and high hydration ability of GO-Ca-alginate nanohydrogels. The separation efficiencies of various oil-water mixtures were above 99 %, with a highest flux of 119,426 L m^-2 h^-1. Hybrid mesh showed an orderly layered "brick and mortar" microstructure with many ultrasmall nanoscaled protuberances. Ca²⁺ ions could chelate with SA to form the "egg-box" structure, and interact with GO nanosheets. Hybrid mesh possessed high salt/acid/alkaline tolerance, abrasion resistance, mechanical property with Young's modulus of 35.8 ± 4.9 GPa, and excellent cycling stability.

Novel bio-inspired three-dimensional nanocomposites based on montmorillonite and chitosan

In this study, inspired by nacre-like structural natural shells, novel three-dimensional (3D) nanocomposites based on natural nanoplatelets of montmorillonite (MMT) and polysaccharide of chitosan (CS) were prepared with solution intercalation and self-assembly process. The CS-intercalated-MMT nanoplatelets units acted as "bricks" and CS molecules acted as "mortar", arranging in fairly well-ordered layered structure. With addition of glutaraldehyde (GA) and Pd²⁺ cations, synergistic toughening and strengthening effects of covalent and ionic bonds could be achieved. The best mechanical properties of the prepared 3D nanocomposites were observed as 5.6 KJ/m² (impact strength), 3.3 GPa (flexural modulus), and 65.8 MPa (flexural strength), respectively, which showed higher toughness but lower flexural properties than natural pearl mussel shells. Nevertheless, both the impact and flexural properties of the prepared 3D nanocomposite were much higher than the other natural shell, i.e. green grab shell. Besides conventional methods characterizations, the nacre-like structure of the artificial 3D nanocomposite was further evidenced with positron annihilation lifetime spectroscopy characterizations. This work might facilitate a versatile platform for developing green 3D bionanocomposites with fairly good mechanical properties.

Self-assembled matrix fabricated by Fe-metal organic frameworks and carboxymethyl cellulose for the determination of small molecules by MALDI-TOF MS

A nanoprobe of laser desorption/ionization-time of flight mass spectrometry (LDI-TOF MS) for the determination of small molecules was developed that is based on the composition of Fe-metal organic frameworks (Fe-MOFs) and carboxymethyl cellulose-Na (CMC-Na). This material is a good adsorbent for small molecules via hydrogen bonding and π-interactions; we detected three molecules, dopamine, glyphosate, and pyrene. The detection limits for these compounds are 0.01 mg L^-1, 1.50 μg L^-1, and 0.01 μg L^-1, respectively; the recoveries are 85-117%, 81-127%, and 89-115%, respectively. The relative standard deviations (~ 15%) and coefficients of determination of the calibration plot (~ 0.97) are satisfactory. The applicability of the chip for practical samples is demonstrated by quantifying pyrene in domestic water and polluted lake water; the recoveries are about 90~117% and 85~125% (n = 5), respectively; the RSDs are 9.4% and 13.5%, respectively. Graphical abstract.