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Cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) were used to improve the mechanical properties of tapes and yarns produced from natural fibers as a new application of cellulose nanomaterials in textile-based composite products. Hemp and flax slivers were used as natural fibers for the production of yarns and tapes. CNC, unground CNF and two different ground CNF suspensions were used as the reinforcement agents. Fiber strands from each natural fiber were soaked in the cellulose nanomaterial suspension and then were processed into tapes or yarns. Individual hemp and flax fibers where also soaked in the same suspensions and dried. SEM microscopy of the surfaces and cross-sections of the yarns and tapes showed that cellulose nanomaterial suspensions affected the morphology of the natural fiber yarns and tapes by filling gaps and adhering the fibers together. Results of studies on tensile properties of single fibers showed improvement in initial modulus and strength of flax fibers after soaking in nanocellulose suspensions especially when CNF was used. Such consistent results were not however seen for hemp single fibers. Yarns and tapes produced by soaking fiber strands in different nanocellulose suspensions had considerably higher tensile properties in terms of strength and initial modulus than controls. Furthermore, it was shown that mixing cellulose nanomaterial suspensions with natural fibers improved the dewatering/drying process, a necessary step should cellulose nanomaterials be used in composite applications. [ABSTRACT FROM AUTHOR]

Cellulose nanofibrils (CNF) were spun into filaments directly from suspension without the aid of solvents. The influence of starting material properties and drying temperature on the properties of filaments produced from three different CNF suspensions was studied. Refiner-produced CNF was ground using a microgrinder at grinding times of 50 and 100 minutes. Filament spinning was performed using a syringe pump-heat gun setting at three drying temperatures of 210 °C, 320 °C and 430 °C. The structure of starting CNF materials was first evaluated using a combination of optical and atomic force microscopy (AFM) techniques. Surface free energy analysis and attenuated total reflectance--Fourier transform infrared spectroscopy (ATR-FTIR) were used to study changes in hydrophobicity due to grinding. Morphology of the filaments was studied using SEM micrographs. The influence of different drying temperatures and grinding times on mechanical properties of the CNF filaments were further investigated through tensile tests and results were compared using statistical analysis. It was observed that drying temperature did not significantly influence the tensile properties of the filaments while cellulose nanofiber suspension type (grinding time) had a significant influence and improved mechanical properties. FTIR results confirmed an increase in crystallinity index and decrease in hydroxyl group availability due to grinding. [ABSTRACT FROM AUTHOR]

An organic–inorganic core/shell structure, γ-Fe 2 O 3 /polyrhodanine nanocomposite with γ-Fe 2 O 3 nanoparticle as core with average diameter of 15 nm and polyrhodanine as shell with thickness of 1.5 nm, has been synthesized via chemical oxidation polymerization and applied for adsorption of Zn ions from aqueous solution in a fixed-bed column. The properties of nanocomposite were characterized with transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM). The performance of the column was assessed under variable bed heights (10, 15 and 20 cm) and influent Zn concentrations (50, 100 and 150 ppm) at a constant flow rate (0.5 mL/min). The results demonstrated that the breakthrough curves are S-shaped and the breakthrough time increases with increasing bed height and decreases with increasing influent concentration. Moreover, the dynamics of the adsorption process were evaluated by using Adams–Bohart, bed depth service time (BDST), Thomas and Yoon–Nelson kinetic models. The models were nearly in good agreement with the experimental data. [ABSTRACT FROM AUTHOR]

Biocomposites can be both environmentally and economically beneficial: during their life cycle they generally use and generate less petroleum-based carbon, and when produced from the byproduct of another industry or recycled back to the manufacturing process, they will bring additional economic benefits through contributing to a circular economy. Here we investigate and compare the environmental performance of a biocomposite composed of a soybean oil-based resin (epoxidized sucrose soyate) and flax-based reinforcement using life cycle assessment (LCA) methodology. We evaluate the main environmental impacts that are generated during the production of the bio-based resin used in the biocomposite, as well as the biocomposite itself. We compare the life cycle impacts of the proposed biocomposite to a functionally similar petroleum-based resin and flax fiber reinforced composite, to identify tradeoffs between the environmental performance of the two products. We demonstrate that the bio-based resin (epoxidized sucrose soyate) compared to a conventional (bisphenol A-based) resin shows lower negative environmental impacts in most studied categories. When comparing the biocomposite to the fossil fuel derived composite, it is demonstrated that using epoxidized sucrose soyate versus a bisphenol A (BPA)-based epoxy resin can improve the environmental performance of the composite in most categories except eutrophication and ozone layer depletion. For future designs, considering an alternative cross-linker to facilitate the bond between the bio-based resin and the flax fiber, may help improve the overall environmental performance of the biocomposite. An uncertainty analysis was also performed to evaluate the effect of variation in LCA model inputs on the environmental results for both the biocomposite and composite. The findings show a better overall carbon footprint for the biocomposite compared to the BPA-based composite at almost all times, demonstrating a good potential for marketability especially in the presence of incentives or regulations that address reducing the carbon intensity of products. This analysis allowed us to pinpoint hotspots in the biocomposite's supply chain and recommend future modifications to improve the product's sustainability. [ABSTRACT FROM AUTHOR]

Cellulose nanomaterials (CNs) are of increasing interest due to their appealing inherent properties such as bio-degradability, high surface area, light weight, chirality and the ability to form effective hydrogen bonds across the cellulose chains or within other polymeric matrices. Extending CN self-assembly into multiphase polymer structures has led to useful end-results in a wide spectrum of products and countless innovative applications, for example, as reinforcing agent, emulsion stabilizer, barrier membrane and binder. In the current contribution, after a brief description of salient nanocellulose chemical structure features, its types and production methods, we move to recent advances in CN utilization as an ecofriendly binder in several disparate areas, namely formaldehyde-free hybrid composites and wood-based panels, papermaking/coating processes, and energy storage devices, as well as their potential applications in biomedical fields as a cost-effective and tissue-friendly binder for cartilage regeneration, wound healing and dental repair. The prospects of a wide range of hybrid materials that may be produced via nanocellulose is introduced in light of the unique behavior of cellulose once in nano dimensions. Furthermore, we implement some principles of colloidal and interfacial science to discuss the critical role of cellulose binding in the aforesaid fields. Even though the CN facets covered in this study by no means encompass the great amount of literature available, they may be regarded as the basis for future developments in the binder applications of these highly desirable materials. [ABSTRACT FROM AUTHOR]