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The current global warming is driving the use of clean and renewable energy. Intermittence is a drawback of clean energy. Energy storage is the answer to intermittence. Flow batteries, batteries, capacitors, and supercapacitors are among the most used energy storage devices in the world. In this paper, capacitors made from graphite and commercial graphene were fabricated. The obtained specific capacitances reached 851 F g −1 , indicating that the devices meet the performance standard for supercapacitors. The devices were fabricated using cellulose nanocrystals as binding material in the electrode, thus using an environmentally friendly binding material. Cyclic voltammetry revealed a quasi‐rectangular process. Charge–discharge cycles revealed a storage mechanism of electrical double layer. The Warburg impedance indicates the diffusive impedance of electrolyte ions in the devices.

Cellulose nanocrystals (CNCs) are a very versatile material, and optimizing the reaction conditions to obtain them is vital for cost savings, purity, selectivity, or performance. In this study, the reaction conditions of the CNCs were tested, as well as their application as binders for the fabrication of electrodes of a symmetric capacitor (based on activated carbon). The resulting CNCs were physicochemically characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, atomic force microscopy, and its capacitive properties using cyclic voltammetry (CV). It was found that the best reaction conditions were at 45°C, 30 and 45 minutes, and 64 wt%. The CNCs were used as a binder, as they conferred stability to the electrodes and prevented the crumbling of the activated carbon electrodes. The CV measurements showed a capacitor behavior; CNCs can be used in energy storage applications.

Hydroxyethylcellulose (HEC) is a biodegradable, biocompatible polymer which is responsive to the temperature and pH values that can be reached by the human body. Polyacrylamide (PAAm) is a biocompatible and absorbent material which is highly used as a Drug Delivery System (DDS) due to its swelling capacity. In this work, a composite of HEC and PAAm was synthesized at a ratio of 25/75 wt% in order to evaluate its use as a transdermal DDS for acetaminophen. Drug release tests were performed in a phosphate buffer solution (PBS) at 35, 37, and 39 °C. The Korsmeyer-Peppas model was presented as a mathematical optimization problem and solved by Differential Evolution (DE) algorithm. Additionally, drug release data was modelled by Multigene Symbolic Regression (MSR) based on Genetic Programming (GP) algorithm. A drug release mathematical model was generated by MSR. The model is capable to reliably describe the kinetics of acetaminophen release from HEC/PAAm and to predict the concentrations of drug that is released in times beyond the experiment runtime.

The use of organic materials in optics/photonics is highly attractive due to its promising applications in bioimaging, optoelectronic devices, photonic pigments, etc. However, the absence of π units in polysaccharides like cellulose or chitosan represents a disadvantage as these aromatic rings or double bonds are crucial to reduce non-radiative transitions in organic materials. To our knowledge, the mechanism to achieve photoluminescence (PL) in carbohydrate polymers without π units yet to be studied. Herein, we studied the effect of the drying of cellulose samples on PL, analyzing the effect of a thermal treatment by FTIR and UV-Vis. On one hand, the dominant wavelength of all PL spectra is at 520 nm, all samples show an increment in maximum intensity of PL between 29 and 49% and diffuse reflectance after the dehydration. A blueshift was found in the PL spectra, which was confirmed by chromaticity measurements. On the other hand, there is a relationship between the reduction of the adsorbed water and OH intermolecular stretching vibrations (FTIR) and the increment in PL, specifically in bands corresponding to the intermolecular H-bonds of O3-H···O5 and O2-H···O6. According to all data collected, an energy level diagram of cellulose samples was proposed indicating a phonon induced character of luminescence.

Hydrogels are commonly used as Drug Delivery Systems (DDS) as patches due to its ability to store drug molecules within their structures. The release can be activated under certain stimuli, such as temperature and pH. In this paper, the mathematical modelling of acetaminophen release in hydroxypropyl cellulose with polyacrylamide (HPC/PAAm) is reported. The HPC/PAAm gel was synthesized in proportions of 25/75 wt% and was characterized by FTIR, DSC, optical microscopy, SEM, and TGA, with and without acetaminophen. The release tests were performed for hypothermic, normal, and febrile human body conditions, at 35, 37, and 39°C, respectively, on two release media: water and phosphate buffer solution. In order to describe the release of acetaminophen in HPC/PAAm gel, a genetic programming algorithm was used to accomplish Multigene Symbolic Regression (MSR). Characterization results showed that the drug was crystallized on the surface of the HPC/PAAm gel. Release test results showed that several simultaneous processes occurred in the acetaminophen diffusion phenomenon. A unique mathematical model was obtained by MSR. This model was able to describe the release of acetaminophen in HPC/PAAm gel with high values of R2 and adjusted R2 and to simulate the drug release at times beyond the end of the experiment. High values of R2 and low values of Coefficient of Variation (CV), Root-Mean-Square Error (RMSE), and Mean Absolute Error (MAE) were obtained from the comparison between the simulated and the experimental data. This allows to conclude that the mathematical model is reliable to represent and simulate the acetaminophen release in HPC/PAAm gel at 35, 37, and 39°C.

Blends of poly(L-lactic acid)/nanoparticle silver and GTA (plasticizer) are present, and the crystallization effect was studied. The effect of the crystallization was investigated by oxygen permeability, isothermal crystallization, and mechanical behavior. Observed properties varied according to the concentration of Ag-NP (0.025–0.1%) dispersed in the continuous phase PLLA. Overall isothermal crystallization rates of the PLLA nanocomposites were higher than those of neat PLLA due to the nucleating effect of the Ag-NP and the enhanced chain mobility caused by the plasticizer (GTA). Ternary blends exhibited an improvement in toughness compared to PLLA alone. Also, the effect is due to the α and αʹ crystals growing up, as observed by XRD. The films exhibited a high barrier of oxygen permeability from 2118 to 18 cc·mm/m 2 ·d, 99% lower than that of PLLA (or 117 times lower), Ag-NP concentration (0.1%) dispersed in the polymer with GTA as a plasticizer.

Bacterial cellulose (BC) has gained attention in recent years due to its high purity and multiple applications in the biomedical and pharmaceutical fields, and mothers of vinegar are a promising source of low-cost BC that can be easily obtained from any variety of vinegar. Silver nanoparticles (AgNPs) are known for their antimicrobial activity as well as their use as antiseptics on healing wounds. For this research, BC-AgNPs films were synthesized, and their antibacterial activity against Staphylococcus aureus and Escherichia coli was evaluated. The BC films were obtained from mothers of vinegar from two varieties (apple vinegar and cranberry vinegar) and were used as support for AgNPs at 5, 25, 41, 69, 116 and 324 ppm. All the films added with AgNPs achieved growth inhibition of 99–100% for both bacterial species, exhibiting values of antibacterial effectiveness ( R ) between 3.37 and 7.72. The BC-AgNPs films presented a slightly higher antibacterial activity against S. aureus , but the difference was negligible, and the composites were effective to inhibit the growth of both bacteria. The results show that the BC-AgNPs films synthesized from mothers of vinegar have potential for wound-healing purposes and that they are effective with silver concentrations as low as 5 ppm. Graphical Abstract

Monodispersed silver nanoparticles (Ag-NPs) were synthesized by chemical reduction in aqueous medium and transferred in chloroform to be redispersed in the plasticized matrix of poly( l- lactic acid) (PLA) by melt compounding. PLA nanocomposites were prepared using a combination of Ag-NPs in amounts of 0.01, 0.025, 0.05, 0.075 and 0.1% in weight, with 10 pph (parts per hundred) of glycerol triacetate (GTA) to be characterized by UV–Vis and Fourier transformed infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). Optical properties showed that PLA nanocomposites have monodispersed Ag-NPs due to the intense SPR (surface plasmon resonance) absorption band at 414 nm, with a calculated particle size of ~30 nm. The crystallinity is gradually raised at a maximum level (21.1%) compared to the pure PLA (2.3%) and T g drastically decreased from 61 to 36.8 °C when Ag-NPs are incorporated in the plasticized PLA matrix. These results were consistent with the enhanced elastic modulus in DMA analysis, explained from the viewpoint of a good nanofiller dispersion and crystallization behavior, providing a stable and ordered crystal (α-form) in agreement with FTIR and DSC analysis. Finally, the outcomes indicate a synergistic effect between Ag-NPs and the plasticizer GTA, due to the nucleating effect of the monodispersed Ag-NPs and the mobility chain promoted by the plasticizer in the macromolecular arrangement of the PLA.

The reinforcement of polymers with vegetal fibers is experiencing important advances in both its properties and processing as well as in its acceptance by the consumer, maintaining an exponential growth in terms of development and innovation in new composite materials. The focus of this research is given in the study of the potential effect of sargassum particles (SgP) as reinforcement in the thermomechanical properties of a polymeric matrix composed of HIPS and SBS. Three different concentrations of SgP in the matrix 5, 10, and 15 PHR (parts per hundred of additive) were evaluated and compared with a reference of virgin polymers (not modified). The evaluation of the composites in mechanical stress-elongation tests showed results of a Young's modulus higher by 58% with respect to the reference, reaching a maximum value with a content of 15 PHR of particles in the binary matrix. The composites were also evaluated in Fourier transform spectroscopy, as well as in optical microscopy. Graphical abstract

Candelilla bagasse fiber (CBF) was prepared by a mesh sieve and ball-milling process and its reinforcing effect in a polymer matrix analyzed. Composites of polypropylene (PP) and CBF were prepared by melt blending with varying amounts (20, 25, and 30 wt%) of fiber using maleic anhydride PP as coupling agent. The chemical composition of CBF was analyzed according to Technological Association of the Pulp and Paper Industry (TAPPI) methods, and the morphology and thermal and chemical properties of CBF and its composites were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and tensile testing. In general, fibers extracted from candelilla by a reduction process are comparable in terms of micro- and nanostructure to other lignocellulosic fibers. Dynamic light scattering (DLS) results reveal that sieve-milling reduces the fiber size. The results also show that the thermal stability of PP was enhanced when using CBF, but the crystallinity index of the PP composites decreased slightly according to DSC and XRD results. Furthermore, the Young’s modulus was increased in PP/CBF samples with and without MAPP to obtain improved wettability and fiber–polymer adhesion. We found that CBF is an excellent alternative to replace conventional materials or synthetic fibers, as well as for reinforcement in polymer composites.