Increasing Chitosan Concentration Research Articles

Fabrication and characterization of extracted microsized chitosan embedded PVDF membrane for wastewater treatment

Abstract Critical water crisis due to overpopulation, industrialization and urbanization has resulted to the shortfall of providing safe drinking water to one billion people in the world. This work intends to fabricate modified hydrophobic polyvinylidene fluoride (PVDF) membrane by hydrophilic chitosan extracted from waste fish scales for wastewater treatment. Chitosan was blended with PVDF in N-methyl-2-pyrrolidone solution by solution casting method. Three different concentrations of 1, 3 and 5 wt% of chitosan were taken. The morphological, spectral and thermal analysis of the produced films were elaborately studied. The contact angle decreased with the increase of chitosan content from 82.64° to 60.97°. The tensile strength decreases from 1.11 to 0.38 MPa and Young’s modulus decreased from 12.08 to 7.4 MPa with increase in chitosan content in the film from 1 to 3 %. The performance of microparticle embedded membrane was compared with the pristine PVDF membrane, and it was affirmed that the microsized-chitosan embedded PVDF membrane manifests a broad promising application perspective towards wastewater treatment owing to its excellent water flux (76 L m−2 h−1) as well as antibacterial properties.

Extraction and evaluation of chitosan as an insecticide against saw-toothed grain beetle, <i>Oryzaephilus surinamensis</i> L. (Coleoptera: Silvanidae)

Rice samples infested with saw-toothed grain beetles have been collected from a local market in the city of Kirkuk/Iraq. The study was conducted in Kirkuk during the period 15 December 2023 to 25 April 2024, at College of Pure Sciences at the University of Kirkuk, Iraq. Chitosan was utilised in the study to examine its toxic effects at three different concentrations (0.5, 1.0, 1.5 ppm) on the life cycle of the saw-toothed grain beetle, focusing on oviposition rate, duration of larval and pupal stages, and mortality rate of its adults. The chemical demonstrated a substantial effect in lowering the number of eggs laid as the concentration increased, with the control treatment registering the highest oviposition rate of 314.14 eggs compared to 209.31, 117.03, and 61.12 eggs for chitosan concentrations of 0.5, 1.0, and 1.5 ppm, respectively. The shortest egg incubation period recorded was 8.17 days, Incubation times for chitosan treatments increased significantly to 9.66, 11.69, and 14.00 days for concentrations of 0.5, 1.0, and 1.5 ppm, respectively, demonstrating an inverse association with concentration levels. Furthermore, the emergence rate of beetles decreased as concentration increased. The emergence counts for the chitosan treatments at concentrations of 0.5, 1.0, and 1.5 ppm dropped to 133.11, 55.69, and 30.12 beetles, respectively, with the control treatment having the highest average emergence of 289.43 beetles. The larval stage duration showed a direct proportionality with chitosan concentrations, with the 1.5 ppm concentration marking the longest larval duration at 22.00 days, significantly surpassing all other concentrations. The control treatment recorded the shortest duration at 13.56 days, whereas 0.5 and 1.0 ppm concentrations resulted in duration of 17.19 and 19.66 days, respectively. For the pupal stage, significant differences were observed with increasing chitosan concentration; the control treatment displayed the shortest pupal duration at 4.33 days. A direct relationship was found between the concentrations and pupal stage duration, reducing the period to 6.00, 7.59, and 9.07 days for concentrations of 0.5, 1.0, and 1.5 ppm, respectively. Chitosan exhibited significant differences from the second day of the experiment, as the mortality rate increased with concentration and over time. The concentration of 1.5 ppm showed the highest mortality rate at 98.62% after 16 days, whereas the control treatment recorded the lowest rate at 33.17%. Based on the results of the current study, chitosan can be utilized as an effective pesticide for controlling stored-product pests, particularly the saw-toothed grain beetle.

Phytochemical Analysis and Nanoparticle Formulations of Extracts Myristica fragrans Houtt Leaves as Antibacterial

Myristica fragrans Houtt leaves contain secondary metabolites such as flavonoids, terpenoids and alkaloids, which have antibacterial properties. At the nanoscale, the particles have a bigger surface contact area, resulting in increased amounts and solubility of the active chemical. This leads to a stronger antibacterial activity. This study aims to examine the influence of several chitosan variations on particle size, antibacterial properties and the form of nanoparticles produced from Myristica fragrans leaves ethanol extract. Ethanol extract was analyzed using the UV-Vis spectrophotometric method to quantify total flavonoid content. Nanoparticles were synthesized using the ionic gelation technique with several ratios of chitosan and sodium tripolyphosphate, specifically 8:1, 10:1 and 12:1. Nanoparticles were analyzed with a Particle Size Analyzer (PSA) and Scanning Electron Microscopy (SEM). Agar diffusion test for bacteria germs using a paper backer. Myristica fragrans leaves ethanol extract was 50, 40 and 30 %, while nanoparticle extract was 5, 4 and 3 %. The overall flavonoid concentration in the QE/ethanol extract was 39.7252 ± 1.9596 mg. Antibacterial test results against Staphylococcus aureus and Escherichia coli bacteria and Myristica fragrans leaves extract limit inhibition area at 30 % (13.35 mm), 40 % (13.68 mm) and 50 % (13.93 mm) for Staphylococcus aureus and 30 (13.28), 40 (13.45) and 50 % (13.81 mm) for Escherichia coli. Myristica fragrans leaves extract chitosan nanoparticles included 3 (14.70), 4 (15.30) and 5 % (15.56 mm) for Staphylococcus aureus and 3 (14.60), 4 (14.65) and 5 % (15.05 mm) for Escherichia coli. Ionic gelation can create nanoparticles of Myristica fragrans leaves ethanol extract with chitosan and sodium tripolyphosphate. Myristica fragrans leaves nanoparticle ethanol extract exhibits better antibacterial activity than ethanol extract. Increasing chitosan concentration affects particle size. The ethanol extract of Myristica fragrans nanoparticle leaves showed slightly better antibacterial activity than the ethanol extract. HIGHLIGHTS Nanoparticles of extracts and extracts have proven excellent antibacterial activity against human pathogens through paper disc diffusion method. Antibacterial test results against Staphylococcus aureus and Escherichia coli bacteria and Myristica fragrans leaves extract limit inhibition area at 30 % (13.35 mm), 40 % (13.68 mm), and 50 % (13.93 mm) for Staphylococcus aureus and 30 % (13.28 mm), 40 % (13.45 mm), and 50 % (13.81 mm) for Escherichia coli. Myristica fragrans leaves extract chitosan nanoparticles included 3 % (14.70 mm), 4 % (15.30 mm), and 5 % (15.56 mm) for Staphylococcus aureus and 3 % (14.60 mm), 4 % (14.65 mm), and 5 % (15.05 mm) for Escherichia coli. The synthesized extract nanoparticles can be used against human pathogens acts as antibacterial drugs. GRAPHICAL ABSTRACT

Comparison of the Antimicrobial Efficacy of Conventional Versus Chitosan Re-inforced Heat-Polymerized Polymethylmethacrylate Dental Material: An In Vitro Study.

Polymethylmethacrylate (PMMA) is widely used in the fabrication of dentures due to its aesthetic appeal and mechanical strength. However, PMMA's susceptibility to microbial colonization often leads to oral infections such as denture stomatitis. Enhancing the antimicrobial properties of denture materials is crucial for improving patient outcomes.Chitosan, a natural biopolymer, possesses inherent antimicrobial properties and could potentially enhance the microbial resistance of PMMA. This study has investigated thepotential of chitosan-reinforced heat-polymerized PMMA denture material to reduce microbial colonization. The aim of the study was to evaluate and assess the anti-bacterial and antifungal properties of chitosan-reinforced heat-polymerized PMMA with conventional heat-polymerized PMMA Materials and methods:Chitosan-reinforced PMMA samples were fabricated with varying chitosan concentrations (0% control, 5%, 10%, and 15% by weight). The fabrication involved mixing chitosan powder with PMMA powder, adding monomer liquid, followed by mixing, packing, and curing using the conventional heat polymerization technique. The antimicrobial efficacy was assessed in vitro using two common oral pathogens: Streptococcus mutans and Candida albicans. Blood agar plates were used for S. mutans and Sabouraud agar plates were used for C. albicans. Each sample was placed on the respective agar plates inoculated with a standardized microbial suspension and incubated at 37°C for 24 hours. The number of colony-forming units (CFUs) was counted to quantify microbial growth. Statistical analyses, including linear regression analysis, one-way ANOVA test, and Pearson correlation were performed to evaluate the relationship between chitosan concentration and antimicrobial efficacy. The p-value was calculated to determine the statistical significance of the results. The chitosan-reinforced PMMA samples showed significantly greater antimicrobial efficacy compared to the conventional PMMA samples. The CFU counts for both S. mutans and C. albicans decreased with increasing chitosan concentration. Linear regression analysis indicated a strong negative correlation between chitosan concentration and CFU counts, with Pearson correlation coefficients of -0.97 for S. mutans and -0.98 for C. albicans. ANOVA analysis revealed a statistically significant difference in antimicrobial efficacy across different chitosan concentrations (p < 0.001). Incorporating chitosan into heat-polymerized PMMA significantly enhances its antimicrobial properties against S. mutans and C. albicans. The antimicrobial efficacy improves with higher concentrations of chitosan, with the 15% chitosan-reinforced samples showing the most substantial reduction in microbial growth. These results suggest that chitosan-reinforced PMMA dentures could be a superior alternative to conventional PMMA dentures, potentially reducing denture-related infections and improving oral health outcomes for denture wearers.

High-Efficiency Alkyl Ketene Dimer Emulsions Stabilized by Polyaluminum Chloride and Chitosan Complex.

Based on the interaction of polyaluminum chloride (PAC) and chitosan (CTS) at the molecular level, an organic/inorganic composite material was designed for the preparation of alkyl ketene dimer (AKD) emulsion. This paper aimed to explore the influence of PAC/CTS on the physicochemical properties, microstructure, and sizing efficiency of AKD emulsions. The PAC/CTS complex forms a denser adsorption layer at the oil-water interface at the microscopic level. With the increase in CTS concentration, the AKD emulsions displayed excellent stability after high-speed centrifugation. In addition, the addition of CTS can effectively improve the sizing efficiency of the emulsion. Therefore, this study proposed a strategy of PAC/CTS as an emulsifier, and the related interaction mechanism was explored, which further expands the application of inorganic/organic composites in the field of colloidal chemistry.

Preparation and Characterization of Hydrogels Fabricated From Chitosan and Poly(vinyl alcohol) for Tissue Engineering Applications.

In this study, we report on the preparation, characterization, and cytocompatibility of hydrogels for biomedical applications made from two different molecular weights of chitosan (CS) blended with poly(vinyl alcohol) (PVA) and chemically cross-linked with tetraethyl orthosilicate (TEOS) followed by freeze-drying. A series of CS-PVA hydrogels were synthesized with different amounts of chitosan (1%, 2%, and 3% by weight). The structure of these CS-PVA hydrogels was characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The hydrogel samples were also characterized for tensile strength, contact angle, swelling behavior, and degradation at physiological body temperature. Their physicochemical properties, biocompatibility, and cell viability when cultured with human dermal fibroblasts were assessed using alamarBlue and live/dead assays and compared to optimize their functionality. SEM analysis showed that the concentration and molecular weight of the chitosan component affected the pore size. Furthermore, the contact angle decreased with increasing chitosan content, indicating that chitosan increased its hydrophilic properties. The in vitro degradation study revealed a nonlinear time-dependent relationship between chitosan concentration or molecular weight, and the rate of degradation was affected by the pore size of the hydrogel. All of the CS-PVA hydrogels exhibited good cell proliferation, particularly with the high molecular weight chitosan samples.

Swelling, Protein Adsorption, and Biocompatibility of Pectin-Chitosan Hydrogels.

The study aims to determine how chitosan impacts pectin hydrogel's ability to attach peritoneal leukocytes, activate complement, induce hemolysis, and adsorb blood proteins. The hydrogels PEC-Chi0, PEC-Chi25, PEC-Chi50, and PEC-Chi75 were prepared by placing a mixture solution of 4% pectin and 4% chitosan in a ratio of 4:0, 3:1, 2:2, and 1:3 in a solution of 1.0 M CaCl2. Chitosan was found to modify the mechanical properties of pectin-calcium hydrogels, such as hardness and cohesiveness-to-adhesiveness ratio. Chitosan in the pectin-calcium hydrogel caused pH-sensitive swelling in Hanks' solution. The PEC-Chi75 hydrogel was shown to adsorb serum proteins at pH 7.4 to a greater extent than other hydrogels. PEC-Chi75's strong adsorption capacity was related to lower peritoneal leukocyte adherence to its surface when compared to other hydrogels, showing improved biocompatibility. Using the optical tweezers approach, it was shown that the force of interaction between pectin-chitosan hydrogels and plasma proteins increased from 10 to 24 pN with increasing chitosan content from 0 to 75%. Thus, the properties of pectin-calcium hydrogel, which determine interactions with body tissues after implantation, are improved by the addition of chitosan, making pectin-chitosan hydrogel a promising candidate for smart biomaterial development.

Tuning the rheological properties of chitosan/alginate hydrogels for tissue engineering application

Biomaterials that mimic biological tissues are in great demand in tissue engineering. Hydrogels are rising as a conducive candidate in tissue engineering on account of their water-holding capacity, mechanical strength, and elasticity. Nevertheless, the development of hydrogels that mimic biological tissues with the desired stability and mechanical strength, remains a notable barrier. In this investigation, chitosan/alginate hydrogels were prepared by tuning the chitosan concentration from 0.5 % to 2.5 %w/v with a fixed 1 %w/v alginate concentration using 0.1 % glutaraldehyde as a gelling agent. The hydrogel system forms through covalent bonding between chitosan and alginate, mediated by aldehyde groups of the glutaraldehyde. The mechanical strength of the hydrogel was elucidated by probing its viscoelastic behavior through rheological analysis. The rheological investigations revealed that the prepared chitosan/alginate hydrogels are profoundly stable with shear-thinning characteristics. The increase in chitosan concentration enhanced the stability and viscoelastic attributes of the hydrogels. The yield stress values ranging from 0.93 kPa to 14.24 kPa indicate the possibility of using these hydrogels in bioadhesives and soft and bone tissue engineering. The complex modulus of the prepared chitosan/alginate hydrogels resembles the shear modulus of liver tissues, osteogenic cells, and articular cartilage, and hence, these hydrogels pose as suitable candidates in liver, bone, and cartilage tissue engineering. The chitosan/alginate hydrogels possess outstanding self-healing ability, along with biocompatibility, stability, and mechanical strength, rendering them highly advantageous for applications in biomedical tissue engineering and bioadhesives.

Thixotropic chitosan hydrogels for biomedical applications: Unravelling the effect of chitosan concentration on the mechanical behaviour

Chitosan hydrogels are highly sought after in biomedical applications due to their biocompatibility, non-toxicity, and tunable mechanical properties. Nevertheless, achieving stable hydrogels with the required mechanical strength remains a notable obstacle. In this study, we prepared chitosan hydrogels with enhanced stability using minimal concentrations of glutaraldehyde to mitigate toxicity risks. The resulting hydrogel system is characterized by strong covalent bonds formed through imine and hydrogen bonding, facilitated by the aldehyde groups of glutaraldehyde. Rheological analyses reveal the viscoelastic properties of the hydrogels, showcasing stable gel-like structures with shear-thinning behavior, which are further enhanced with increasing chitosan concentration. Our observation demonstrates that the complex shear moduli of 0.5 - 1.5 w/v% chitosan hydrogel ranged between 3.08 kPa and 8.5 kPa, closely matching the shear moduli of the brain and connective tissues. The shear moduli obtained for the 2 w/v% (10.2 kPa) and 2.5 w/v% hydrogels (11.34 kPa) conform to the shear moduli of liver, fat, relaxed muscle, and breast gland tissue. Thixotropic studies reveal good structural recovery behaviour in the hydrogels. The swellability of 2 w/v% and 2.5 w/v% hydrogels (50–70 %) suggests their suitability for bone tissue engineering, with moderate porosity required for bone growth (60–75 %). Moreover, the yield stress values of 0.5 - 1.5 w/v% hydrogels satisfy the requirements for soft tissue engineering, while those of 2 and 2.5 w/v% match the requirements for bone tissue engineering. Our findings suggest that chitosan hydrogels of varying concentrations (0.5–2.5 % w/v) hold promise for a range of biomedical applications, including tissue engineering for brain, nerve, soft, and bone tissues, and wound dressing. This research addresses the pressing need for stable chitosan hydrogels with tailored mechanical properties, potentially offering solutions to challenges in biomedical materials design.

Impact of Molar Composition on the Functional Properties of Glutinous Rice Starch-Chitosan Blend: Natural-Based Active Coating for Extending Mango Shelf Life.

This study investigates natural-based blends of glutinous rice starch (GRS) and chitosan (CS), varying their molar composition (0:100, 30:70, 50:50, 70:30, and 100:0) to explore their interaction dynamics. Our findings illustrate the versatility of these blends in solution and film forms, offering applications across diverse fields. Our objective is to understand their impact on coatings designed to extend the post-harvest shelf life of mangoes. Results reveal that increasing chitosan content in GRS/CS blends enhances mechanical strength, hydrophobicity, and resistance to Colletotrichum gloeosporioides infection, a common cause of mango anthracnose. These properties overcome limitations of GRS films. Advanced techniques, including FTIR analysis and stereo imaging, confirmed robust interaction between GRS/CS blend films and mango cuticles, improving coverage with higher chitosan content. This comprehensive coverage reduces mango dehydration and respiration, thereby preserving quality and extending shelf life. Coating with a GRS/CS blend containing at least 50% chitosan effectively prevents disease progression and maintains quality over a 10-day storage period, while uncoated mangoes fail to meet quality standards within 2 days. Moreover, increasing the starch proportion in GRS/CS blends enhances film density, optical properties, and reduces reliance on acidic solvents, thereby minimizing undesirable changes in product aroma and taste.

Comparative study on the effects of chitosan, carrageenan, and sodium alginate on the film-forming properties of fish skin gelatin

Polysaccharides are commonly used to improve the film-forming properties of gelatin due to their wide range of sources, safety, and edible properties. However, there has been no systematic study comparing the effects of different polysaccharides on the film-forming properties of gelatin. Effects of chitosan, carrageenan, and sodium alginate on the optical properties, mechanical properties, thermal stability, hydrophilicity, and structure properties of gelatin films were systematically compared. Adding chitosan effectively reduced the ultraviolet transmittance of gelatin film. With an increase in chitosan concentration from 2 g/L to 8 g/L, the melting transition temperature (Tm) of gelatin film increased from 74 °C to 101 °C. Additionally, water vapor permeability decreased from 2.2 ± 0.23 (g.mm)/m2.h.kpa to 1.2 ± 0.18 (g.mm)/m2.h.kpa and water solubility decreased from 75% to 66%. Adding carrageenan and sodium alginate respectively increased the Tm of gelatin film to 92 °C and 84 °C; however, their addition reduced hydrophobicity and elongation at break for gelatin films. X-ray diffraction results suggested good compatibility between gelatin and all three polysaccharides while Fourier transform infrared spectrum results confirmed hydrogen bond interaction between gelatin and polysaccharides with a more orderly structure observed in gelatin films after adding polysaccharides.

Economic Approach for Synthesis of Gold Nanoparticle-based Freeze Indicator for Fish Products

This study was conducted during the period September 2020–January 2023 at ICAR-Central Institute of Fisheries Technology, Cochin. The study was to develop a cost-effective freeze indicator using gold nanoparticles. Gold nanoparticles (AuNPs) were synthesized using chitosan and trisodium citrate (TSC) as a reducing agent. Various chitosan samples with different molecular weights were obtained from commercial chitosan units. Chitosan was employed at two distinct concentrations. The UV-Vis spectra exhibited the characteristic peak of AuNPs at 520–530 nm in all analyzed samples. The samples containing chitosan displayed a light pink color, whereas those containing TSC exhibited a ruby red color. An increase in chitosan concentration led to an increase in absorbance of the SPR peak. The full width at half maximum (FWHM), zeta potential, and conductivity of the nanoparticles were also investigated. The stability of the synthesized nanoparticles was assessed during frozen storage at -18°C, revealing that the sample containing TSC became colorless upon freezing. The stability of chitosan-containing samples improved with higher concentrations and molecular weights. No distinct color change upon freezing was observed in the samples synthesized using chitosan. The AuNPs synthesized using TSC were evaluated and the significant color change demonstrated by the sample confirmed that the nanoparticle solution synthesized using TSC at a gold concentration of 1 mM can serve as an effective freeze indicator for food and pharmaceutical applications.

Development of Poly(vinyl alcohol)-Chitosan Composite Nanofibers for Dual Drug Therapy of Wounds.

Current trends in localized drug delivery are emphasizing the development of dual drug-loaded electrospun nanofibers (NFs) for an improved therapeutic effect on wounds, especially infected skin wounds. The objective of this study was to formulate a new healing therapy for an infected skin wound. To achieve this goal, this study involved the development and characterization of poly(vinyl alcohol) (PVA)/chitosan nanofibers loaded with ciprofloxacin and rutin hydrate. Polymers and drugs were used in different ratios. Nanofiber morphology was studied by scanning electron microscopy, thermal stability by thermogravimetric analysis, structural determination by the X-ray diffraction method, and integrity by Fourier transform infrared spectroscopy. Dissolution studies were performed to check the drug release behavior of the formulations. Antibacterial studies were performed against Staphylococcus aureus and Pseudomonas aeruginosa. The wound healing efficiency of dual drug-loaded nanofibers was measured by a full-thickness excisional wound model of rabbits. The fabricated nanofibers were smooth in morphology. According to FTIR findings, the drugs remained intact in the nanofibers. The results of swelling ratio and porosity revealed that the pore size was increased as the amount of chitosan was increased up to 30% but a further increase in chitosan concentration reduced the swelling ratio and porosity. Drug release studies of nanofibers depicted an initial burst effect and afterward controlled drug release behavior. Drug-loaded nanofibers showed better activity against S. aureus than P. aeruginosa. The antibacterial efficacy of rutin hydrate with ciprofloxacin was improved compared to that of the formulation having rutin hydrate only, likely due to the additive effect in activity. Based on wound healing studies, nanofibrous membranes acted as a promising wound dressing material as compared to the commercial wound healing formulation. Drug-loaded polymeric nanofibers were successfully fabricated by using an electrospinning method. These nanofibers showed an efficient ability to deliver drugs and treat infected wounds.

Utilization of chitosan as an additive for enhancing the performance of polyethersulfone membranes for water treatment

This research investigates the impact of adding chitosan as an additive to improve membrane performance. Membrane fabrication was conducted using the non-solvent-induced phase separation method with polymer blending. Characterization was conducted by evaluating functional groups using FTIR, morphological structure using SEM, and water contact angle using a WCA meter. The research findings show that chitosan additives have a positive influence on the prepared PES membrane. There was a change in the morphological form on the membrane, as evidenced by SEM photos of the cross-section of the membrane. An increase in chitosan concentration resulted in improved hydrophilic properties of the membrane, indicated by a 63.2° reduction in water contact angle. The results show that the best membrane performance was achieved with 4% chitosan addition, resulting in a water flux of 38.2 L/m2.h as well as humic acid rejection of 67.9%.

Utilizing chitosan and pullulan for the encapsulation of Lactiplantibacillus plantarum ZJ316 to enhance its vitality in the gastrointestinal tract

Lactiplantibacillus plantarum ZJ316 has demonstrated effective alleviation of gastritis and colitis, making it crucial to improve its viability within the gastrointestinal tract. In this study, Chitosan (CS) and pullulan (PUL) encapsulated nanofibers of ZJ316 were prepared using electrospinning, considering both the synergistic effects of prebiotics and probiotics and their protective effects. We found that increasing the CS ratio resulted in elevated conductivity of the polymer solution, while decreasing viscosity and pH. Scanning electron microscopy showed that at a CS: PUL ratio of 1:135, polymer filaments were difficult to form, and nanofiber diameter decreased with higher CS content. X-ray diffraction analysis confirmed the miscibility of CS and PUL, while ATR-FTIR demonstrated the presence of hydrogen bonding interactions between the two materials. Thermal analysis indicated that an increased CS concentration improved the thermal stability of the nanofibers. Based on these findings, the optimal CS:PUL ratio for electrospinning was determined to be 1:60. Encapsulation of ZJ316 in the nanofibers significantly enhanced its survival rate in simulated gastrointestinal fluid compared to free bacteria, with survival rates of 87.24 % (gastric) and 79.71 % (intestinal), respectively. This study provides valuable insights for the development of probiotic functional foods.

Effect of chitosan on the insulation and smoke absorption properties of expanded vermiculite composites

ABSTRACT In order to improve the thermal insulation and smoking properties of expanded vermiculite matrix composites, a kind of expanded vermiculite (EV)/chitosan (CS) composites was prepared by hot pressing. The effects of CS on smoke density, fire-resistance, insulation, and mechanical properties of the EV/CS composites were studied. The results show that with the increase of CS content, the smoke absorption performance and energy storage modulus of the composites is improved. Thermogravimetric (TG) analysis shows that the thermal stability of the EV/CS composite is improved by the presence of chitosan. The pores appear on the surface of the composites after the single-side fire-resistance test. After that, the thermal conductivity of the composites gradually decreases and the insulation performance is improved as the CS content increases. The CS carbonized during the preparation of the composites and thermal decomposition during the test. The morphology results show phase separation of the composites, and the porosity of the composites increases after the test. The reticular structure formed between the EV particles, sodium silicate, and CS molecules reduces the strength loss of the composites.

Ethyl cellulose-chitosan microspheres of sumatriptan succinate for nasal drug delivery

The research investigated the preparation of mucoadhesive microspheres using ethyl cellulose and chitosan as polymers. Two methods were employed, with the first method utilizing an emulsion solvent evaporation technique and the second method incorporating additional homogenization and sonication steps. The results showed that the first method yielded nearly perfect spherical microspheres with a particle size range of 50 µm, while the second method produced irregularly shaped microspheres with larger particle sizes within the range of 200 µm. The drug entrapment efficiency was significantly higher in the first method compared to the second method, and within the first method, drug entrapment efficiency decreased with increasing chitosan concentration. These findings underscore the importance of method selection and chitosan concentration in microsphere synthesis, providing insights for optimizing drug delivery systems for targeted applications.

Optimisation of Chitosan as A Natural Flocculant for Microplastic Remediation

The objective of this study is to determine the optimal concentration of chitosan for microplastic remediation using the coagulation-flocculation method. The chitosan concentrations employed in this study include 10, 20, 30, and 40 ppm. The process of coagulation was conducted for one minute, with a rotational speed of 120 rpm. The process of flocculation was performed for 30 minutes with a rotational speed of 60 rpm. The findings of the study indicate that chitosan demonstrates a high efficacy in microplastic removal, resulting in a removal rate of 68.3%. Furthermore, the research findings indicate that the optimal concentration of chitosan for microplastic remediation was determined to be 30 ppm. The concentration of chitosan has a direct impact on the pH, TDS, COD, and BOD values. In general, an increase in chitosan concentration leads to a drop in pH and TDS values; conversely, an increase in chitosan concentration results in a rise in COD and BOD values.

Analysis of the morphological and mechanical characterization of aluminium matrix composite reinforced with chitosan

Recent studies acknowledge that convectional ceramic particulate could be replaced by several agricultural by-products in the development of aluminium matrix composites because of its selected for their low cost and relative ubiquity. This study explores the development of aluminium matrix composite from AA6061 alloy reinforced with chitosan particulates at weight proportions (3, 6, 9, and 12 wt%). The study further characterizes the developed composites using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffractometer (XRD), hardness, tensile and thermal and electrical conductivity test techniques. Results indicated that increasing chitosan content up to 10 wt% enhanced the hardness performance, while tensile strength of the composites increased sporadically, as SEM images observed reinforcement links embedded in grain boundaries. However, the thermal and electrical conductivity diminished due to the addition of chitosan particulates to the alloy matrix. The overall study showed the great potential of chitosan polymer as reinforcement to aluminium alloy.

FEASIBILITY STUDY ON PREPARATION OF RICE STRAW NONWOVEN COATED WITH CHITOSAN FOR REACTIVE DYE ADSORPTION

Rice straw is the most abundant agricultural waste material in Thailand. Therefore, this research was interested in utilizing rice straw and adding value by preparing a reactive dye bioadsorbant. The aims of this research were to prepare rice straw nonwovens by the wet-laid process, study chitosan-coated nonwovens by the dip coating method, and evaluate the reactive dye adsorption capacity of the coated nonwovens. The ratio of weight per unit area of the prepared nonwovens was controlled. The nonwovens were dipped in chitosan solutions (0.5, 1, and 1.5 wt% of chitosan) to prepare chitosan coated nonwovens. Reactive dye adsorption capacity, chemical structure, morphology, and physical properties of the nonwovens were investigated. It was found that rice straw nonwoven coated with chitosan increased in thickness, hardness, and water resistance properties with increasing chitosan concentration. Chitosan-coated nonwoven, at 15% chitosan concentration and a contact time of 72 hours, was able to adsorb 38.40% of the reactive azo dye, C.I. Reactive Blue 194 (50 mg/L). The dye absorbency of the chitosan-coated nonwovens increased with the increase in the chitosan-coated concentration and the contact time. In addition, the chitosan-coated nonwovens could remain on rice straw cellulose nonwoven surfaces under reactive dye immersion for at least 72 hours without change. The results indicated that rice straw nonwovens coated with chitosan by the dip coating method had reactive dye adsorption abilities.