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One of the activities most representative of the agricultural sector in Colombia is the production of biodegradable fique fiber. The efficiency of the defiberization process of the fique leaves is very low since a mere 4% of the total weight of the leaf ( cabuya ) is used and marketed. The remaining 96%, composed of fique juice and bagasse, is considered to be waste and discarded, impacting the environment. The aim of this work was to study fique bagasse as a source of cellulose nanoparticles (CNCs). CNCs were obtained by acid hydrolysis and added at 10% to films made from cassava thermoplastic starch (TPS) by the casting method. Structural changes in the CNCs, TPS, and their mixtures were characterized by FTIR-ATR and their morphology and particle size by SEM and TEM microscopy, respectively. Thermal properties were analyzed using DSC and TGA, along with their effect on mechanical properties. Changes in the FTIR spectra indicated that the chemical method adequately removed hemicellulose and lignin from the fiber surface of fique bagasse. The CNCs showed a diameter and length of 7.5 ± 3.9 and 52.7 ± 18.1 nm, respectively, and TPS 10% CNC obtained an increase in mechanical strength of 116%. The obtainment of CNCs from lignocellulosic materials can thus be viewed as a favorable option for the subsequent reinforcement of a polymeric matrix.

This present study optimized the cellulose nanofiber (CNF) loading and melt processing conditions of poly(3-hydroxybutyrate- co -3-hydroxyhexanoate) P(HB- co -11% HHx) bionanocomposite fabrication in twin screw extruder by using the response surface methodology (RSM). A face-centered central composite design (CCD) was applied to statistically specify the important parameters, namely CNF loading (1-9 wt.%), rotational speed (20-60 rpm), and temperature (135-175 °C), on the mechanical properties of the P(HB- co -11% HHx) bionanocomposites. The developed model reveals that CNF loading and temperature were the dominating parameters that enhanced the mechanical properties of the P(HB- co -11% HHx)/CNF bionanocomposites. The optimal CNF loading, rotational speed, and temperature for P(HB- co -11% HHx) bionanocomposite fabrication were 1.5 wt.%, 20 rpm, and 160 °C, respectively. The predicted tensile strength, flexural strength, and flexural modulus for these optimum conditions were 22.96 MPa, 33.91 MPa, and 1.02 GPa, respectively, with maximum desirability of 0.929. P(HB- co -11% HHx)/CNF bionanocomposites exhibited improved tensile strength, flexural strength, and modulus by 17, 6, and 20%, respectively, as compared to the neat P(HB- co -11% HHx). While the crystallinity of P(HB- co -11% HHx)/CNF bionanocomposites increased by 17% under the optimal fabrication conditions, the thermal stability of the P(HB- co -11% HHx)/CNF bionanocomposites was not significantly different from neat P(HB- co -11% HHx).

The present research work intended to demonstrate the green synthesis of silver nanoparticles (AgNPs) using the plant extract Saccharum officinarum , and then the development of chitosan-silver (CH-Ag) bionanocomposite. The synthesized AgNPs were characterized using UV spectroscopy, Fourier transform infrared (FTIR), and transmission electron microscopy (TEM). The maximum absorption spectrum peak was observed at 420 nm, revealing the formation of AgNPs by the stem extract of S. officinarum . The AgNPs sizes were in the range of 10-50 nm. Itraconazole is an antifungal that is used as a novel drug to study its release through synthesized bionanocomposite. Different kinetic models, such as zero order, first order, Korsmeyer-Peppas, Hixson-Crowell and Higuchi, were used to study the drug release profile from the synthesized CH-Ag bionanocomposite. The first-order kinetic model showed the best fit for the drug release with the maximum regression coefficient value. The antibacterial activity of the synthesized CH-Ag bionanocomposite was examined against Bacillus cereus , Staphylococcus , and Escherichia coli , and it was shown to be efficient against these strains.

A unique morphological Sesamum radiatum oil/polyvinylpyrrolidone/gold polymeric bionanocomposite film was synthesized using the S. radiatum oil dispersed in a polymeric polyvinylpyrrolidone (PVP) matrix and decorated with gold nanoparticles (AuNPs). The chemical and physical characteristics as well as the thermal stability of the synthesized bionanocomposite film were investigated using various spectroscopic and microscopic techniques. The microscopic analysis confirmed well dispersed AuNPs in the PVP- S. radiatum oil matrix with particle size of 100 nm. Immunomodulatory and antiprotozoal potentials of the suggested bionanocomposite film were evaluated for lipopolysaccharide-induced BV-2 microglia and against L. amazonensis , L. mexicana promastigotes and T. cruzi epimastigotes, respectively. The results exerted outstanding reduction of inflammatory cytokines' (IL-6 and TNFα) secretions after pretreatment of bionanocomposite. The bionanocomposite exhibited large inhibitory effects on certain cell signaling components that are related to the activation of expression of proinflammatory cytokines. Additionally, AuNPs and bionanocomposite exhibited excellent growth inhibition of L. mexicana and L. amazonensis promastigotes with IC 50 (1.71 ± 1.49, 1.68 ± 0.75) and (1.12 ± 1.10, 1.42 ± 0.69), respectively. However, the nanomaterials showed moderate activity towards T. cruzi . All outcomes indicated promising immunomodulatory, antiprotozoal, and photocatalytic potentials for the synthesized S. radiatum oil/PVP/Au polymeric bionanocomposite.

Pectin-based antibacterial bionanocomposite films were prepared by crosslinking with calcium chloride (CaCl 2 ) and mixing with zinc oxide nanoparticles (ZnO-NPs) at various concentrations (0.5%, 1%, and 1.5% w/w , based on pectin). Crosslinking with 1% CaCl 2 significantly ( p < 0.05) improved the tensile strength of the pectin films, although their elongation at break was decreased. The UV-light barrier property of the pectin/ZnO bionanocomposite films was significantly ( p < 0.05) improved with increasing ZnO-NP concentrations. In addition, the bionanocomposite films incorporating 1.5% ZnO-NPs showed excellent antibacterial effects against both Escherichia coli and Staphylococcus aureus , inhibiting over 99% of the bacteria. Therefore, the developed crosslinked pectin/ZnO bionanocomposite films show great potential as active packaging materials with excellent UV-blocking and antibacterial properties.

The major hurdle in melt-processing of ultra-high molecular weight polyethylene (UHMWPE) nanocomposite lies on the high melt viscosity of the UHMWPE, which may contribute to poor dispersion and distribution of the nanofiller. In this study, UHMWPE/cellulose nanofiber (UHMWPE/CNF) bionanocomposites were prepared by two different blending methods: (i) melt blending at 150 °C in a triple screw kneading extruder, and (ii) non-melt blending by ethanol mixing at room temperature. Results showed that melt-processing of UHMWPE without CNF (MB-UHMWPE/0) exhibited an increment in yield strength and Young's modulus by 15% and 25%, respectively, compared to the Neat-UHMWPE. Tensile strength was however reduced by almost half. Ethanol mixed sample without CNF (EM-UHMWPE/0) on the other hand showed slight decrement in all mechanical properties tested. At 0.5% CNF inclusion, the mechanical properties of melt-blended bionanocomposites (MB-UHMWPE/0.5) were improved as compared to Neat-UHMWPE. It was also found that the yield strength, elongation at break, Young's modulus, toughness and crystallinity of MB-UHMWPE/0.5 were higher by 28%, 61%, 47%, 45% and 11%, respectively, as compared to the ethanol mixing sample (EM-UHMWPE/0.5). Despite the reduction in tensile strength of MB-UHMWPE/0.5, the value i.e., 28.4 ± 1.0 MPa surpassed the minimum requirement of standard specification for fabricated UHMWPE in surgical implant application. Overall, melt-blending processing is more suitable for the preparation of UHMWPE/CNF bionanocomposites as exhibited by their characteristics presented herein. A better mechanical interlocking between UHMWPE and CNF at high temperature mixing with kneading was evident through FE-SEM observation, explains the higher mechanical properties of MB-UHMWPE/0.5 as compared to EM-UHMWPE/0.5.

Palygorskite is a natural fibrous clay mineral that can be used in several applications, for which colloidal stability in aqueous suspensions is a key point to improve its performance. In this study, methods of magnetic stirring, high-speed shearing, and ultrasonication, as well as different chemical dispersants, combined with these methods, namely carboxymethylcellulose, alginate, polyphosphate, and polyacrylate, were used to improve the dispersibility and the formation of stable suspensions of palygorskite in different conditions of pH. The stability and particle size of suspensions with a low concentration of palygorskite were evaluated by visual inspection, optical and electron microscopy, dynamic light scattering, and zeta potential measurements. Moreover, the palygorskite used in this work was initially characterized for its mineralogical, chemical, physical, and morphological properties. It was found that more stable suspensions were produced with ultrasonication compared to the other two physical treatments, with magnetic stirring being inefficient in all tested cases, and for higher pH values (pH of 12 and pH of 8, the natural pH of the clay) when compared to lower pH values (pH of 3). Remarkably, combined with ultrasonication, carboxymethylcellulose or in a lesser extent polyphosphate at near neutral pH allowed for the disaggregation of crystal bundles of palygorskite into individualized crystals. These results may be helpful to optimize the performance of palygorskite in several domains where it is applied.

A series of PLA/ZnO bionanocomposite films were prepared by introducing positively surface charged zinc oxide nanoparticles (ZnO NPs) into biodegradable poly(lactic acid) (PLA) by the solvent casting method, and their physical properties and antibacterial activities were evaluated. The physical properties and antibacterial efficiencies of the bionanocomposite films were strongly dependent on the ZnO NPs content. The bionanocomposite films with over 3% ZnO NPs exhibited a rough surface, poor dispersion, hard agglomerates, and voids, leading to a reduction in the crystallinity and morphological defects. With the increasing ZnO NPs content, the thermal stability and barrier properties of the PLA/ZnO bionanocomposite films were decreased while their hydrophobicity increased. The bionanocomposite films showed appreciable antimicrobial activity against Staphylococcus aureus and Escherichia coli . Especially, the films with over 3% of ZnO NPs exhibited a complete growth inhibition of E. coli. The strong interactions between the positively charged surface ZnO NPs and negatively charged surface of the bacterial membrane led to the production of reactive oxygen species (ROS) and eventually bacterial cell death. Consequently, these PLA/ZnO bionanocomposite films can potentially be used as a food packaging material with excellent UV protective and antibacterial properties., Competing Interests: The authors declare no conflicts of interest.

The properties of a composite material depend on its constituent materials such as natural biopolymers or synthetic biodegradable polymers and inorganic or organic nanomaterials or nano-scale minerals. The significance of bio-based and synthetic polymers and their drawbacks on coating film application is currently being discussed in research papers and articles. Properties and applications vary for each novel synthetic bio-based material, and a number of such materials have been fabricated in recent years. This review provides an in-depth discussion on the properties and applications of biopolymer-based nanocomposite coating films. Recent works and articles are cited in this paper. These citations are ubiquitous in the development of novel bionanocomposites and their applications.