Ratio Of Chitosan Research Articles

UTILIZATION OF CASSAVA TUBERS (DIOSCOREA ALATA) AND CHITOSAN TO PRODUCE BIODEGRADABLE PLASTIC

Plastic is a synthetic compound made from petroleum, which is very useful for various household and industrial purposes. This is due to the many superior properties of plastic compared to other materials. However, on the other hand, plastic made from petroleum raw materials still has several weaknesses, including product safety for health and after use it will become waste that is difficult to degrade, thus polluting the environment. Apart from that, the supply of petroleum raw materials is increasingly depleting and non-renewable. Plastic can be produced from raw materials that are safer for health and the environment. Several studies on the manufacture of biodegradable plastic have been carried out using raw materials in the form of organic materials whose main content is starch, however the strength and elasticity of the resulting plastic is still low. Therefore, in this research we will study the manufacture of biodegradable plastic from tubers that are not properly utilized, namely yam tubers (discorea alata) with the addition of chitosan as a reinforcement. This research was carried out by mixing the materials, heating then molding and drying. The variables studied include process temperature, process time, and the mass ratio of chitosan to starch. Next, mechanical tests were carried out, namely tensile strength and elongation, FTIR tests, and biodegradation tests with EM4 bacteria. The research was carried out using the variables process temperature, process time, and chitosan:starch mass ratio. Based on the results of research carried out with raw materials such as yam tubers and chitosan, optimal conditions were obtained using a time of 90 minutes, a stirring speed of 300 rpm, a temperature of 80 oC, and a mass ratio of chitosan to starch of 0.075. With these conditions, plastic was obtained with a tensile strength of 7.80 MPa and an elongation of 16.37%. Biodegradable plastic from yam tubers and chitosan can be degraded with the help of EM4 bacteria for 35 days, so the biodegradable plastic from yam tubers is environmentally friendly plastic.

Construction of chitosan modified cationic lipid droplet emulsions for high-value microalgae harvesting

To reduce the risk of microalgae biomass and environmental contamination, a natural cationic lipid droplet emulsion has been constructed for harvesting microalgae. Using three different microalgae strains (Chlorella vulgaris, Scenedesmus quadricauda and Spirulina platensis), the present work studied the influence of lipid droplet dosage, chitosan concentration, pH on harvesting efficiency, and then the flotation behavior was analyzed by zeta potentials, floc size distribution, algal organic matter component, attenuated total reflectance Fourier transform infrared spectrometer and microscopic observation. The XDLVO theory was used to explain the attachment behavior during the flotation process. The experimental results showed that the maximum harvesting efficiency for two green microalgae strains was over 95% at pH 7, while the optimal dosage and ratio of lipid droplet and chitosan were depended on the microalgae species. The maximum harvesting efficiency for Spirulina platensis was less than 70% since the high salinity of growth medium weakened the bridging and netting ability of chitosan. The mechanism of capturing microalgae by the ballasting agents was mainly physical electrostatic attraction, bridging and netting. In addition, the changes of microalgae components before and after harvesting were less than 5%, indicating this method would not affect the downstream application of microalgae biomass.

Layer-by-layer self-assembled liposomes prepared using sodium alginate and chitosan: Insights into vesicle characteristics and physicochemical stability

In this study, layer-by-layer self-assembled liposomes were prepared with different mixing ratios (3:7, 1:1, and 7:3) of sodium alginate (SA) and chitosan (CS), and the morphology, structure, and physicochemical properties of liposomes after layer-by-layer coating were investigated. After coating the liposomes with SA-CS layer-by-layer (S–C-L), the particle size of liposomes increased from 244.50 to 423.33 nm, the potential changed from negative to positive to 21.20 mV, and the PDI was only 0.393. In the S–C-L 7:3 formulation, the liposomes were uniformly distributed and spherical in size with a clear fingerprint structure. In addition, S–C-L reduced the number of hydrophobic regions within the molecule, allowing the phospholipid molecules to bind tightly into stacks, thus making the liposomes more stable. The S–C-L 7:3 formulation effectively improved the tolerance of liposomes to strong acids and bases, high-salt environments, and UV exposure, and maintained a constant particle size of 400 nm after 28 days of storage. The findings of this study might contribute to the development of polysaccharide layer-by-layer modification of liposomes for a more stable liposomal transport system.

Preparation of cross-linked chitosan magnetic microspheres and immobilization of pectinase

Abstract In this paper, the kinetic model under the influence of each factor is given by investigating the effects of distribution effect, external diffusion effect and internal diffusion effect on the immobilized pectinase reaction system. The magnetic chitosan microspheres were prepared by the reversed-phase suspension cross-linking method, and the effects of the type and amount of cross-linking agent and the ratio of chitosan to magnetic core incorporation on the performance of the magnetic spheres were investigated. Then, the immobilized pectinase was prepared by using cross-linked chitosan magnetic microspheres as a carrier, and an orthogonal test was used to determine the conditions of immobilized enzyme preparation and to study the enzymatic properties and operational stability of immobilized pectinase. The results showed that the transmittance of the magnetic microspheres of this test increased from 32% to 90.79% in 10 min in a magnetic field, but in a gravity field, the transmittance increased from 32.12% to 46.44% in 50 min. The experimentally prepared microspheres exhibit good magnetic responsiveness. The optimum temperature of immobilized pectinase was 50°C, and the remaining enzyme activity was still 61.24% after 6 repetitions. The immobilized pectinase made by crosslinking glutaraldehyde with chitosan magnetic microspheres has a high recovery of enzyme activity and good operational stability, as indicated by this.

Fabrication and optimization of febuxostat-loaded chitosan nanocarriers for better pharmacokinetics profile

The current research was planned to enhance the bioavailability of hydrophobic drug after oral administration through the development of a nanoparticle drug delivery system (DDS). Therefore, febuxostat-loaded chitosan nanoparticles (FLC NPs) were prepared using a modified ionic gelation method and optimized the reaction conditions through the design of experiments. Design expert software was used to check the desirability of the central composite design and the interactive effects of the independent variables (chitosan concentration, ratio of chitosan to linker, and pH of the medium) on the response variables (size distribution, zeta potential, polydispersity index (PDI), and entrapment efficiency (EE)) of FLC NPs. All ingredients of the optimized formulation (formulation Q) were compatible with each other as evident from FTIR, PXRD, and TGA studies, and displayed 234.7 nm particle size, 0.158 PDI, 25.8 mV zeta potential, and 76.9 % EE. TEM, SEM, and AFM exhibited a smooth, dense, and uniform structure without any visible pores in the structure of FLC NPs. The in vitro and in vivo drug release studies described a sustained release pattern of febuxostat and increased relative bioavailability by 286.63 %. Considering these findings, this chitosan nanoparticle DDS can further be used for improving the EE and bioavailability of hydrophobic drugs.

Development of Active Antibacterial CEO/CS@PLA Nonwovens and the Application on Food Preservation.

The biodegradable activity antibacterial materials have been widely applied on food preservation because they not only protect foods from pathogenic attacks but also relieve environmental pollution. Biodegradable melt-blown nonwovens (MB) have several advantages over the other materials in terms of a simpler and more environmentally friendly fabrication process, higher specific surface area, and lower cost. Herein, polylactic acid (PLA) MB is first modified by polydopamine (PDA) to activate the surface. Then, chitosan (CS) and cinnamon essential oil (CEO) are used to decorate the surface of the modified PLA MB via a simple one-pot method to prepare CEO/CS@PLA MB with different CEO contents. Compared with PLA MB, CEO/CS@PLA MB had a rougher surface and larger average fiber diameter, while the average pore diameter and air permeability reduced. The input of CEO led to a decrease in the tensile strength of CEO/CS@PLA MB and an obvious increase in the elongation at break. The combination of CS and CEO shows excellent synergistic antibacterial effect. The antibacterial efficiencies of CEO/CS@PLA MB against Escherichia coli and Staphylococcus aureus enhance with the increase of the CEO content. When the weight ratio of CS to CEO is 1:2, the antibacterial efficiencies of CEO2/CS@PLA MB against E. coli and S. aureus are 99.98 and 99.99%, respectively. When being applied to the preservation of fresh strawberry, CEO2/CS@PLA MB can effectively inhibit the microbial growth in strawberry and reduce decay, which extends the shelf time of strawberry.

DEVELOPMENT, CHARACTERIZATION, AND EVALUATION OF THE ANTIMICROBIAL PROPERTIES OF BIODEGRADABLE POROUS SCAFFOLDS LOADED WITH NATURAL VANILLIN

Objective: The study's objective is to create biodegradable porous scaffolds that are filled with natural vanillin and assess their in vitro antibacterial activity. Methods: Scaffolds were fabricated by blending different ratios of chitosan and gelatin along with vanillin using the freeze-drying method. Then the following characterization and evaluation of scaffolds, such as FTIR, SEM, porosity, swelling behaviour, degradation studies, in vitro drug release, and antibacterial studies, were carried out. Results: All of the scaffolds that were created had heterogeneous, well-connected pores and were pale yellow in color. This was validated by SEM, where the porosity is greater than 80% and the mean pore size ranges from 105.25±6.35 µm to 188.58±7.51 µm. With an increase in gelatin concentration, all of the scaffolds showed the maximum water absorption and retention capabilities of 760.15%±4.38% and 664.73%±5.82%. In the 7-day degradation investigation, all samples lost close to 60% of their mass. In the formulation CG11, the vanillin was released gradually over about 96 h. According to the present study, the developed scaffolds CG13-A and CG13-B, as well as CG11-A and CG11-B, displayed a higher zone of inhibition. Conclusion: Due to its potent antibacterial capabilities, it may be inferred from the current research that vanillin clothed in chitosan-gelatin scaffolds would be a superior option for treating various wound infections, including diabetic wounds.

A Green Method for Nanoencapsulation of Thymol in Chitosan–Gelatin with Antioxidant Capacity

AbstractNanostructures are usually formed by solvent dissolution, but this paper proposes a green-chemistry method for thymol nano-encapsulation based on a chitosan–gelatin bio-copolymer matrix formation that enhances the physical stability to obtain a thymol-modified release system, with antioxidant capacity. Various ratios of chitosan–gelatin, gelatin types A and B, and crosslinkers were evaluated at a constant thymol concentration of 0.5 mg/ml. Gallic acid was chosen as the crosslinker. All batches were ultrasonicated to reduce particle size. The best conditions were obtained using a chitosan–gelatin ratio of 1:4 with type A gelatin, as those nanoparticles had higher physical stability, together with a smaller particle size (316.5 ± 2 nm) and higher thymol encapsulation efficiency (88 ± 3%). Antioxidant capacity was evaluated by DPPH, ABTS (radical inhibition 87.06 ± 4.38%, and 88.5 ± 4.42%, respectively), and a FRAP assay (1084.68 ± 54.32 µM Trolox equivalents). Release profiles were evaluated at two pH values (5.5, 7.0) and environmental temperatures (4, 25 °C). Diffusion was non-Fickian in all treatments. Gelatin type A systems exhibited a major physical stability, influencing the reduction of released thymol significantly. The research findings suggest that this submicronic dispersion can be used as a modified release system with high antioxidant activity and potentially serve as a preservative system during food storage.

Development of Chitosan/Sodium Carboxymethylcellulose Complexes to Improve the Simvastatin Release Rate: Polymer/Polymer and Drug/Polymer Interactions' Effects on Kinetic Models.

Simvastatin (SIM) is a potent lipid-lowering drug used to control hyper-cholesterolemia and prevent cardiovascular diseases. SIM presents low oral bioavailability (5%) because of its low aqueous solubility. In this work, polyelectrolyte complexes (PEC) are developed with different chitosan (CS) and carboxymethylcellulose (CMC) ratios that will allow for an increase in the SIM dissolution rate (2.54-fold) in simulated intestinal medium (pH 4.5). Scanning Electron Microscopy (SEM) images revealed highly porous structures. The changes between both complexes, PEC-SIM:CS:CMC (1:1:2) and (1:2:1), were related to the relaxation of the polymer chains upon absorption of the dissolution medium. Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and powder X-ray diffraction (XRPD) studies were used to evaluate the polymer/polymer and drug/polymer interactions on the different PEC-SIM:CS:CMC ratios. In addition, the PEC-SIM:CS:CMC (1:2:1) complex exhibited a high ratio of protonated amino groups (NH3+) and an increase in intramolecular hydrogen bonds, which were correlated with a high expansion of the interpolymer chains and an increase in the SIM dissolution rate. Different kinetic models such as zero-order, first-order, Higuchi and Korsmeyer-Peppas were studied to evaluate the influence of CS/CMC ionic interactions on the ability to improve the release rate of poorly soluble drugs.

Si@C anode with excellent electrochemical performance for lithium-ion batteries: Microcapsules composed of N-doped carbon shell and diffusely distributed nano-silicon inside

As a promising candidate for the next generation of new anode materials, the modification and optimization of silica-based anode materials are significant. Using chitosan (CS) as the carbonaceous precursor, the N-containing Si@C microcapsules were prepared by emulsification cross-linking combined with high-temperature pyrolysis method. The microcapsule structure offers additional space for nano-Si and effectively enhances the electrochemical properties of the anode. Moreover, optimizing the CS:Si ratio is advantageous in achieving a synergistic effect between silicon and carbon. When CS:Si = 4:1, the first specific capacity was 762.78 mAh/g and the retention rate was 69.27 % after 100 cycles. To further enhance the material properties, urea was added to a ratio of CS:Si = 4:1 as an N supplement for elemental doping modification. The specific capacity of the anode had a positive correlation with N content within a certain range. As the N content increases, the pyridine-N content and density of C vacancies also increase, which improves the storage form and diffusion path of Li+. When 0.75 g urea was added, the first reversible specific capacity reached 1108.88 mAh/g and the retention rate was 92.41 % after 100 cycles. This work offers environmentally friendly and safe methods, as well as a new modification concept for N-doped microsphere-encapsulated silicon-carbon composites.

Preparation and properties of a multi-crosslinked chitosan/sodium alginate composite hydrogel

Wound dressings play an important role in promoting wound healing, and hydrogels with high water content, biocompatibility, and elasticity have broad application in wound dressings. In this study, we have successfully prepared chitosan/sodium alginate /tannic acid (CST) composite hydrogels by dissolving and mixing chitosan/sodium alginate with alkali/urea/water solution and cross-linking multiple times with epichlorohydrin, calcium chloride and tannic acid in turn. The results showed that the CST-31 prepared with a mass ratio of chitosan to sodium alginate at 3:1 had appropriate mechanical properties, high porosity and water retentivity, good biocompatibility and strong antibacterial activity, and could rapidly promote wound healing in mice. In conclusion, CST-31 has an important application prospect as a wound dressing.

Adsorptive elimination of methylene blue dye from aqueous solution by chitosan‐nSiO2 nanocomposite: Adsorption and desorption study, scale‐up design, statistical, and genetic algorithm modeling

AbstractHeavy metals and organic dyes in water in concentrations exceeding the tolerable limit are unsafe for aquatic life and humans. Chitosan nanocomposites show a potential adsorption capacity to organic dyes. The present study encompasses the preparation of chitosan‐nSiO2 nanocomposites (CSNC) with different weight ratios of chitosan to nSiO2 and its application in the methylene blue (MB) dye adsorption. The nanocomposites were characterized with the help of SEM, BET, FTIR, XRD, and TGA. The adsorption experimentation was executed in batch mode under varying experimental conditions. Several isotherm and kinetic models were analyzed with the experimental data, and thermodynamic conditions required for adsorption were also determined. Maximum Langmuir adsorption capacities (qL) of the adsorbents for MB varied in the range of 21.32–31.34 mg g−1. The pseudo‐second‐order model was the best‐fitted kinetic model concerning all three adsorbents. The statistical modeling using multiple polynomial regression (MPR) for CWS CSNC1‐1 and CSNC2‐1 yielded the equations with R‐square ranging from 0.984 to 0.996. For GA modeling, it is more than 0.999. So, the efficient employment of statistical modeling, and genetic algorithms has also been achieved.

Multivariable analysis of egg white protein-chitosan interaction: Influence of pH, temperature, biopolymers ratio, and ionic concentration.

The influence of pH, temperature, biopolymer ratio, total concentration, and ionic concentration on the interaction between egg white protein (EWP) and chitosan (CS) was investigated through turbidity, zeta potential, and state diagram in our research. In addition, phase behavior was observed under various conditions. The turbidity of EWP remained low (turbidity<0.03) and basically unchanged at a wide range of pH (4.0-8.0), while the turbidity of CS was slightly higher (turbidity<0.2) after pH 7.0 than before. Moreover, under the same conditions, a sharply rising peak pattern was observed for the complex between EWP and CS. The maximum turbidity value was observed at 55°C, and the temperature had a mild effect on turbidity. The optimum EWP to CS ratio was found to be 12:1 based on the turbidity curves and state diagrams influenced by different biopolymer mixing ratios. With the enhanced concentrations of total biopolymer, the maximum turbidity rose insignificantly above 0.1%.

Investigating the Correlation Between Drug Physical Properties and Physical Characteristics and Drug Entrapment Efficiencies of Chitosan-TPP Nanoparticles

Chitosan nanoparticles (NPs) have been the subject of intensive research. This study aimed to determine how different drug characteristics such as molecular weights, drug solubility in the processing medium, and drug ionization/charge state affected chitosan NPs particularly their percentage entrapment efficiency (% EE) and mean hydrodynamic diameters (MHDs). Drugs with varying molecular weights but of similar aqueous solubilities were chosen and were dissolved in a 2% chitosan-acetic acid solution. Chitosan NPs were formed using by ionic gelation technique using sodium tripolyphosphate (TPP) at specific concentration and volume ratios of chitosan to TPP. NPs containing Enalapril and Paracetamol displayed better short-term stability in terms of MHDs. A direct relationship between MHDs of NPs and chitosan concentrations was found. In comparison, at both low and high admixed drug concentrations and at high chitosan concentration, larger NPs sizes were associated with the lower molecular weight drug (Paracetamol). However, the study did not demonstrate a direct relationship between NPs characteristics such as MHDs and drugs molecular weights. The ZP of Paracetamol-loaded NPs was lowest at high drug concentrations at all chitosan concentrations compared to other drugs-loaded NPs. When compared to drugs with high and low molecular weights, medium molecular weight Atenolol showed the highest % EE. This clearly indicated that there was no direct correlation between drug molecular weight and % EE, but rather other factors influenced on % EE. Nevertheless, an inverse linear relationship with high correlation coefficients was only found when % EE was plotted against each drug molecular weight divided by the ratio of drugs solubilities in acetic acid to their employed concentrations, however the correlation was inconsistent between drugs of varying molecular weights.

Evaluation of Antimicrobial and Structural Properties of Thyme Essential Oil-Loaded Chitosan-Capric Acid and Chitosan-Stearic Acid Nanogels

&#x0D; &#x0D; &#x0D; Background: This study aimed to investigate the physicochemical properties, antimicrobial activity, and cytotoxicity of Thyme Essential Oil (TEO) encapsulated by chitosan nanogels.&#x0D; Methods: In this study, chitosan-stearic acid and chitosan-capric acid nanogels were developed in two ratios of chitosan to fatty acid (10: 1 and 10: 3).&#x0D; Results: The results of Fourier-Transform Infrared Spectroscopy analysis showed a successful binding of chitosan to capric and stearic acids. Scanning Electron Microscope images revealed that particle formation improved with increase of the ratio of fatty acid to chitosan. The antimicrobial capacity of both encapsulation systems on three species of microorganisms (Staphylococcus aureus, Escherichia coli, and Candida albicans) was studied. A sustained release of curcumin was observed in Simulated Intestine Fluid. The developed nanogels did not have any toxicity on different cell lines. The results also showed that the antimicrobial capacity of TEO encapsulated with chitosan nanogels was higher (p&lt;0.05) than the ionic method (use of sodium triphosphate incorporating chitosan).&#x0D; Conclusion: The results have shown that encapsulating TEO in chitosan nanogels is a suitable alternative for synthetic antibiotics in different products.&#x0D; &#x0D; &#x0D;

THERMAL PROPERTIES OF CROSS-LINKED POLYMERS BASED ON CHITOSAN AND POLYACRYLAMIDE

The thermal properties of cross-linked polymers based on chitosan and polyacrylamide were studied. Samples of the resulting network polymers, which included chains of polyacrylamide and chitosan, were obtained as hydrogel materials by radical polymerization of acrylamide in the presence of chitosan using the redox system of cerium (IV) ammonium nitrate as an initiator and N,N’-methylene-bis-acrylamide as a crosslinker. The structure of the obtained polymers was confirmed by comparing their IR spectra with the spectra of chitosan and polyacrylamide. It was shown that in the IR spectrum of the chitosan-containing sample, the peak at 2932 cm -1 indicates the presence of CH2 groups in the polymer chains and the formation of cross-links. Deformation and valence vibrations of the amide group in polyacrylamide are observed at 1600–1660 cm -1, and the band at 1633 and 1411 cm -1, which appears when the amide bond of polyacrylamide is formed, corresponds to C-N vibrations in the graft copolymer. These characteristic bands confirm the possibility of graft copolymerization of acrylamide on chitosan. The influence of the mass ratio of chitosan and polyacrylamide on the thermal properties of polymer systems was investigated by the method of thermogravimetric and differential thermogravimetric analysis. Atmospheric gas (1 bar, 40 % relative humidity) was used in all thermoanalytical measurements. The samples were examined after vacuum drying at 4 × 10-7 bar and 60 °C using Concentrator Plus. TGA and DTG curves were obtained in the temperature range from 30 to 500 °C with a scanning speed of 5 °C/min using 40 μl aluminum oxide crucibles. It was established that increasing the concentration of chitosan during synthesis reduces the amount of bound water in the obtained samples. Analysis of thermal destruction at the final stages of heating indicates that the presence of chitosan in samples of cross-linked polymers increases their heat resistance by 10–15 °C. The obtained regularities can be used in the creation of composite materials for hydrogel wound dressings and covering medical agents for external use.

PLA stereocomplex-chitosan nanoparticles loaded with tenofovir alafenamide as a long-acting antiretrovirals

Antiretroviral therapy (ART) is a major method of HIV and AIDS treatment; however, it has several limitations, such as poor drug availability, cytotoxicity or renal clearance of the drug molecules. The drugs can be encapsulated in biocompatible polymeric nanocarriers to overcome these limitations. Therefore, the NPs composed of different ratios of poly(l-lactide) PLLA, poly(d-lactide) PDLA, and chitosan (CHI) were prepared by spray-drying technique. Subsequently, the NPs were loaded with the antiretroviral drug - tenofovir alafenamide (TAF). The influence of process variables and nanoparticles (NPs) composition on particle size, drug encapsulation and release was investigated. Finally, it was proved that obtained formulations are non-toxic, and their antiviral efficiency was quantified by JurkatE6 cells infected with HIV. Our findings ascertain that PLLA/PDLA/CHI nanocarriers have great potential for delivering anti-HIV therapeutics.

Application of low-, and medium-molecular weight chitosan for preparation of spray-dried microparticles loaded with Ferulago angulata essential oil: Physicochemical, antioxidant, antibacterial and in-vitro release properties

The present work aimed at spray-drying encapsulation of Chavir (Ferulago angulata) essential oil (EO) using low-, and medium-molecular weight chitosan. The obtained EO was observed to be mainly composed of β-ocimene, α-pinene, and bornyl acetate with antioxidant, and antimicrobial activity. The results indicated that stable emulsions with uniform particle size distribution and encapsulation efficiencies higher than 93 % could be prepared using chitosan as feed for spray-drying. In addition, spray-drying resulted in fabricating stable microspheres with yields higher than 50 %, uniform particle size, and encapsulation efficiency exceeding 70 %. The microspheres were fairly soluble and hygroscopic, and exhibited antioxidant and bacteriostatic activities with a biphasic release pattern. FTIR characterisation confirmed successful encapsulation of EO and thermal properties of microspheres indicated enhanced stability of EO after microencapsulation. Overall, it was revealed that molecular weight of chitosan and EO:chitosan ratio affects some physicochemical properties of obtained chitosan microspheres.

Bioelectricity Generation Using a Crosslinked Poly(vinyl alcohol) (PVA) and Chitosan (CS) Ion Exchange Membrane in Microbial Fuel Cell

&lt;p&gt;Microbial fuel cells (MFCs) are a bioelectrochemical system where electrochemically active bacteria convert organic waste into electricity. Poly(vinyl alcohol) (PVA) and chitosan (CS) are polymers that have been studied as potential alternative ion exchange membranes to Nafion for many electrochemical systems. This study examined the optimal mixing ratio of PVA and chitosan CS in a PVA:CS composite membrane for MFC applications. PVA:CS composite membranes with 1:1, 2:1, and 3:1 ratios were synthesized and tested. The water uptake and ion exchange capacity, Fourier transform infrared spectra, and scanning electron microscopy images were analyzed to determine the physicochemical properties of PVA:CS membranes. The prepared membranes were applied to the ion exchange membrane of the MFC system, and their effects on the electrochemical performance were evaluated. These results showed that the composite membrane with a 3:1 (PVA:CS) ratio showed comparable performance to the commercialized Nafion membrane and produced more electricity than the other synthesized membranes. The PVA:CS membrane implemented MFCs produced a maximum power density of 0.026 mW cm&lt;sup&gt;−2&lt;/sup&gt; from organic waste with stable performance. Therefore, it can be applied to a cost-effective MFC system.&lt;/p&gt;

Mechanical Properties and Liquid Absorption of Calcium Phosphate Composite Cements.

Calcium phosphate cements present increased biocompatibility due to their chemical composition being similar to that of the hydroxyapatite in the hard tissues of the living body. It has certain limitations due to its poor mechanical properties, such as low tensile strength and increased brittleness. Thus, the optimal way to improve properties is through the design of novel composite cements. The purpose was fulfilled using a 25% hydroxyethyl methacrylate (HEMA) mixed with 3% urethane dimethacrzlate (UDMA) base matrix with various ratios of polyethylene glycol (PEG 400) and polycaprolactone (PCL). Mineral filler is based on tricalcium phosphate (TCP) with different chitosan ratio used as bio-response enhancer additive. Four mixtures were prepared: S0-unfilled polymer matrix; S1 with 50% TCP filler; S2 with 50% chitosan + TCP filler; and S3 with 17.5% chitosan + TCP mixed with 17.5% nano hydroxyapatite (HA). The mechanical properties testing revealed that the best compressive strength was obtained by S2, followed by S3, and the worst value was obtained for the unfilled matrix. The same tendency was observed for tensile and flexural strength. These results show that the novel filler system increases the mechanical resistance of the TCP composite cements. Liquid exposure investigation reveals a relative constant solubility of the used filler systems during 21 days of exposure: the most soluble fillers being S3 and S2 revealing that the additivated TCP is more soluble than without additives ones. Thus, the filler embedding mode into the polymer matrix plays a key role in the liquid absorption. It was observed that additive filler enhances the hydrophobicity of UDMA monomer, with the matrix resulting in the lowest liquid absorption values, while the non-additivated samples are more absorbent due to the prevalence of hydrolytic aliphatic groups within PEG 400. The higher liquid absorption was obtained on the first day of immersion, and it progressively decreased with exposure time due to the relative swelling of the surface microstructural features. The obtained results are confirmed by the microstructural changes monitored by SEM microscopy. S3 and S2 present a very uniform and compact filler distribution, while S1 presents local clustering of the TCP powder at the contact with the polymer matrix. The liquid exposure revealed significant pore formation in S0 and S1 samples, while S3 and S2 proved to be more resistant against superficial erosion, proving the best resistance against liquid penetration.