High Substitution Synthesis of Carboxymethyl Chitosan for Properties Improvement of Carboxymethyl Chitosan Films Depending on Particle Sizes

This study investigated the effect of chitosan particle sizes on the properties of carboxymethyl chitosan (CMCh) powders and films. Chitosan powders with different particle sizes (75, 125, 250, 450 and 850 µm) were used to synthesize the CMCh powders. The yield, degree of substitution (DS), and water solubility of the CMCh powders were then determined. The CMCh films prepared with CMCh based on chitosan with different particle sizes were fabricated by a solution casting technique. The water solubility, mechanical properties, and water vapor transmission rate (WVTR) of the CMCh films were measured. As the chitosan particle size decreased, the yield, DS, and water solubility of the synthesized CMCh powders increased. The increase in water solubility was due to an increase in the polarity of the CMCh powder, from a higher conversion of chitosan into CMCh. In addition, the higher conversion of chitosan was also related to a higher surface area in the substitution reaction provided by chitosan powder with a smaller particle size. As the particle size of chitosan decreased, the tensile strength, elongation at break, and WVTR of the CMCh films increased. This study demonstrated that a greater improvement in water solubility of the CMCh powders and films can be achieved by using chitosan powder with a smaller size.

Ion Transport Study in Corn Starch-NaHSO3 Based Polymer Electrolytes

In this work, different amounts of sodium bisulfite, NaHSO3 (5wt.% to 40wt.%), were dissolved in a corn starch polymer host to synthesize solid polymer electrolyte (SPE) using a solution casting technique. Then, the films prepared were characterised using non-destructive electrical impedance spectroscopy to determine SPE films' conductivity and electrical transport properties. The highest conductivity of the sample at ambient temperature was recorded at 15wt. % of NaHSO3 with a value of 2.22 × 10-4 Scm-1. Moreover, the ion transport parameters at room temperature are found to be 2.41 × 10-7 cm2s-1, 9.39 × 10-6 cm2V-1s-1, 1.70 × 1019 cm-3 for D, µ and n, respectively. The conductivity of the samples was found dependent on diffusion coefficient, D and mobility, µ of ions.

The Effect of CoFe2O4, CuFe2O4 and Cu/CoFe2O4 Nanoparticles on the Optical Properties and Piezoelectric Response of the PVDF Polymer.

Cobalt ferrite, Copper ferrite and cobalt doped copper ferrite nanoparticles have been synthesized and characterized using different characterization methods (XRD, FTIR and FESEM). The prepared nanoparticles have been used as promising fillers of the polyvinylidene fluoride (PVDF) polymer. The PVDF/(Cu-CoFe2O4, CoFe2O4, and CuFe2O4) nanocomposites films have been prepared via a simple solution casting technique. The optical properties and the piezoelectric response of the prepared nanocomposite films have been studied. The study showed that Cu-CoFe2O4, CoFe2O4, and CuFe2O4 have enhanced the interfacial polarization density and dielectric constant. The optical conductivity value of PVDF/ (Cu-CoFe2O4 and CoFe2O4) increased five times compared with the pure PVDF. Also, an increase in the piezoelectric response has been recorded by adding the nano-fillers to the pure PVDF.

Effect of ultrahigh diluted homeopathic medicines on the electrical properties of PVDF-HFP

In an effort to improve the electrical properties of the electroactive Poly(vinylidene fluoride-hexafluoropropylene) (PVdF-HFP), we introduced a novel and simple approach to synthesize PVDF-HFP composite films by incorporating ultrahigh dilutions of two homeopathic medicines Ferrum metallicum (FM) and Zincum oxidatum (ZO) in different potencies. The homeo-PVDF-composite films (HPCF) were synthesized by simple solution casting technique. XRD, FESEM, FTIR studies were performed to check the presence of nanoparticles in the film. The electrical properties of the HPCF samples get enhanced significantly due to the incorporation of the medicines and the effect increases with the increase in potency of the medicines.

Synthesis and Characterization of Proton Conducting Polymer Electrolytes based on Poly (N-vinyl pyrrolidone) and Polyvinylchloride

Poly (N-vinyl pyrrolidone) (PVP), Polyvinylchloride (PVC) blend membrane doped with different molar weight percentage of NH4Br has been prepared by solution casting technique using dimethyleformamide (DMF) as solvent and characterized for electrical properties. The prepared polymer electrolyte has been studied by XRD, FT-IR, Dielectric and Capacitance measurements. The XRD results show that the amorphous nature of PVP has increased in 70%PVP: 30%PVC. It is also observed that the amorphous nature of 70%PVP: 30%PVC is further increased by the addition of different concentration of NH4Br. A complex formation of PVP: PVC, PVP: PVC: NH4Br have been confirmed by FT-IR studies. Proton conductivity for the above film has been measured using impedance spectroscopy. The polymer blends 70%PVP: 30%PVC shows an ionic conductivity of 8.46X10-8 Scm-1. The conductivity of the blend film increases as concentration of NH4Br increases. The maximum proton conductivity 2.78X10-3 Scm-1 has been observed for 70%PVP: 30%PVC: 0.6 Molar weights (MWt) NH4Br. The primary proton battery with configuration of Zn + ZnSO4.7H2O/70PVP:30PVC: 0.6 Mwt% NH4Br/PbO2 + V2O5 are fabricated and tested.

Effect of glycerol plasticizer loading on the physical, mechanical, thermal, and barrier properties of arrowroot (Maranta arundinacea) starch biopolymers

This research was set out to explore the development of arrowroot starch (AS) films using glycerol (G) as plasticizer at the ratio of 15, 30, and 45% (w/w, starch basis) using solution casting technique. The developed films were analyzed in terms of physical, structural, mechanical, thermal, environmental, and barrier properties. The incorporation of glycerol to AS film-making solution reduced the brittleness and fragility of films. An increment in glycerol concentration caused an increment in film thickness, moisture content, and solubility in water, whereas density and water absorption were reduced. The tensile strength and modulus of G-plasticized AS films were reduced significantly from 9.34 to 1.95 MPa and 620.79 to 36.08 MPa, respectively, while elongation at break was enhanced from 2.41 to 57.33%. FTIR analysis revealed that intermolecular hydrogen bonding occurred between glycerol and AS in plasticized films compared to control films. The G-plasticized films showed higher thermal stability than control films. The cross-sectional micrographs revealed that the films containing 45% glycerol concentration had higher homogeneity than 15% and 30%. Water vapour permeability of plasticized films increased by an increase in glycerol concentrations. The findings of this research provide insights into the development of bio-degradable food packaging.

Synthesis and Physicochemical Studies of Polyvinyl Alcohol Polymer Modified with Copper Thiosemicarbazide Complex

Thiosemicarbazones (TSCs) represent a category of chemical compounds that attract diverse research groups' attention due to their wide and extended applications in different pharmaceutical and agrochemical applications. Complexation reactions between the ligand and CuCl2 resulted in the formation of [Cu2(H2MTS)Cl2(H2O)4 ]. X-ray diffraction data analysis of the studied complex suggests octahedral structure, while characterization through elemental, thermal, magnetic, and spectral (UV, IR, NMR, and ESR) analyses showed the formation of the complex. Thin films of pure polyvinyl alcohol and other samples containing different mass fractions of CuTSCs were successfully prepared through the traditional solution casting technique. Studies of the synthesized thin films show a notable change of crystallinity, optical band gap, refractive index, dielectric primitivity, and other physical properties with increasing copper complex. Besides, synthesized samples show an observed activity against different pathogenic grams. Increasing copper complex content also shows a prominent change in different samples' swelling rates, suggesting that metal complex acts as a controlled cross-linker for polyvinyl alcohol (PVA) polymer.

Properties of Gel Polymer Electrolyte Based Poly(Vinylidine Fluoride-сo-Hexafluoropropylene) (PVdF-HFP), Lithium Perchlorate (LiClO4) and 1-Butyl-3-Methylimmidazoliumhexafluorophosphate [PF6]

This study reported the preparation and characterization of gel polymer electrolyte (GPE) using poly (vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP), lithium perchlorate (LiClO4) and 1-butyl-3-metilimmidazoliumhexafluorophosphate [PF6]. The GPE were prepared by solution casting technique. [Bmim] [PF6] ionic liquid is used as an additive for the purpose of increasing the ionic conductivity of GPE. Morphological analysis showed that the electrolyte gel polymer sample had a smooth and flat surface with the addition of [Bmim] [PF6] and no phase separation effect was observed. This shows the compatibility between PVdF-HFP and [Bmim] [PF6]. ATR-FTIR analysis showed that C-F bond related peaks experienced peak changes in terms of intensity and peak shifting. This proves the interaction of the imidazolium ion with the fluorine atom through the formation of coordinate bonds. Ionic conductivity analysis showed that PVdF-HFP-[Bmim][PF6] samples reached a maximum room temperature ionic conductivity value of 2.44 × 10-4 S cm-1 at 60 wt.% [Bmim] [PF6]. When 20 wt.% of LiClO4 added to the system, the ionic conductivity increased one magnitude order to 2.20 × 10-3 S cm-1.

Fabrication and Characterization of Chitosan/Cellulose Nanocrystal/Glycerol Bio-Composite Films

Cellulose nanocrystal (CNC)-reinforced bio-composite films containing glycerol were produced using the solution casting technique. The influences of the addition of CNC (2, 4, and 8 wt%) and glycerol (10, 20, and 30 wt%) on the properties of the bio-composite films were studied in the present work. The resulting films were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetry analysis (TGA), and according to their tensile, water absorption, and light transmission behavior. The introduction of 4 wt% CNC into the chitosan film did not affect the thermal stability, but the presence of 20 wt% glycerol reduced the thermal stability. The addition of 4 wt% CNC to the chitosan film increased its tensile strength, tensile modulus, and elongation at break by 206%, 138%, and 277%, respectively. However, adding more than 8 wt% CNC resulted in a drastic reduction in the strength and ductility of the chitosan film. The highest strength and stiffness of the chitosan bio-composite film were attained with 4 wt% CNC and 20 wt% glycerol. The water absorption and light transmission of the chitosan film were reduced dramatically by the presence of both CNC and glycerol.