Polymer Bulletin最新文献

This research investigates the rheological behavior of the Poloxamer–chitosan thermogel system for the release of doxorubicin, which is a chemotherapy agent. To design the experiment, the response surface method was used to optimize the formula and investigate the mutual effects of the variables on the rheological properties of the system. In this experimental design, Poloxamer as a thermogel matrix (15–20%) and chitosan biopolymer as an additive (0.1–0.3%) were used and the pH of the test environment was determined in the range of 2.0–7.5. The results showed that the rheological behavior of the Poloxamer–chitosan combination has the best fit according to the Herschel–Bulkley model with a correlation coefficient of 100%. Also, adding chitosan to Poloxamer decreased the gelation temperature and gelation time. The results showed that the concentration of Poloxamer and chitosan as well as system temperature have a significant effect on the rheological behavior of thermogel. The optimized formula showed favorable rheological properties including high viscosity and appropriate degradation rate. The study showed the sustained release of the drug in the in vitro environment of the thermogel system during 144 h. The kinetics of the drug's release were also studied based on zero-order, first-order, Higuchi, and Korsmeyer–Peppas models. It was found that the Higuchi (R² = 0.9888) and Korsmeyer–Peppas (R² = 0.9851) models are the best models for the prediction of release kinetics of doxorubicin. Therefore, the design of the Poloxamer–chitosan thermogel system has the potential to be used as an in situ drug delivery system for doxorubicin.

This research paper investigates the impact of loading nano-oxides of zinc and copper metal particles into a polyethersulfone (PES) matrix to enhance its structural and mechanical responses. The co-precipitation method was adopted for the synthesis of metallic oxides consisting of zinc and copper. The presence of strain in metallic oxide NPs illustrated in metallic oxide-loaded PES films arises due to the interaction between NPs and PES. As a result of NPs and PES interactions, the particle size of PES has also been increased in PES blended films. Furthermore, we observed that the mechanical properties of PES-loaded films have been improved as the tensile strength was increased from 2.63 to 5.65 MPa, Young’s modulus was enhanced from 8.92 to 10.02 MPa by adding ZnO NPs, whereas the more prominent increase in mechanical properties has been noticed in case of CuO NPs loaded PES blended films. The present work suggested that the loading of nano-oxides in PES enhances the mechanical strength of PES, which may significantly contribute to the field of mechanical engineering as oil level indicators, part for miking machines, and automatic beverage dispensers and pumps. Employing solution casting methodology synthesized metallic oxide NPs were loaded in PES to prepare their blended films. Three major functional groups such as sulfone, benzene, and ether are present in PES, and metal–oxygen vibrational groups have been identified in all prepared polymeric composites by FTIR spectroscopy. The electron microscopy (FESEM) reveals that the oxides of zinc appeared in rod-like structures, copper oxide adopted spherical and rhombus shapes, whereas the composite blended sheets appeared smooth.

Secondary batteries, or rechargeable batteries, have revolutionized various industries by offering the ability to be reused after depletion. Membranes in secondary batteries act as separators, preventing direct contact between electrodes while facilitating ion transport, crucial for energy storage and preventing short circuits. Despite their theoretical ability to be used infinitely, real-time applications face challenges, including the inefficiency of available membranes. This review focuses on the use of chitosan, a biopolymer derived from chitin, in three promising secondary batteries: vanadium redox flow batteries, Aq. zinc batteries, and lithium-ion batteries due to their wide range of applications and promising future scope. For lithium-ion batteries, N-succinyl chitosan-chitosan and chitosan–lithium membranes offer potential improvements in ionic conductivity and mechanical strength, while in Aq. zinc battery chitosan-based carbon membrane and phosphorylcholine zwitterionic protective layer reduces the dendrite formation and alleviates side reactions and for vanadium redox flow battery chitosan modified batteries aim to reduce vanadium ion crossover. Using a chitosan-based membrane increases the energy efficiency of the vanadium redox flow battery to 88.6% from 60% and sustains an Aq. zinc ion battery for up to 2000 cycles. Comprehensively, this review also imparts a roadmap leading to the future prospects of chitosan biopolymer-based secondary batteries to ameliorate the energy density, and overall electrochemical performance of chitosan-derived batteries by modifying the electrode material, for heading toward a green, and sustainable energy storage system.

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Building on traditional emulsion polymerization research, which continues to yield results up to the present day, techniques have emerged to produce hybrid materials. One such technique is Pickering emulsion polymerization, with numerous industrial applications. Despite a growing interest in Pickering emulsion polymerization, the intrinsic mechanisms involved have been based mainly on the findings of classical emulsion polymerization. In this work, by relying on a minimum of assumptions and using a simple model and experimental data on conversion and particle size, we obtain information about the prevailing mechanisms. More specifically, we present four main findings based on data reported previously in the literature. First, in contrast to the three rate-of-reaction intervals reported in classical emulsion polymerization, the integro-differential method yielded only two rate-of-reaction intervals against conversion. Second, a master curve is constructed by plotting the reaction rate against overall conversion, showing a maximum of approximately 55% conversion. Third, despite having a semicontinuous process, monomer concentration inside the particles is not constant. Finally, particle density is a strong function of the Pickering agent concentration, where two fitting parameters (nucleation and coagulation) allowed an accurate description for the particle number time evolution. Both parameters showed a power-law dependence with clay concentration.

This study investigates the simulation of electric field distribution and the characterization of Co₃O₄/carbon nanotube (CNT)-filled polyvinyl chloride (PVC) nanocomposites for potential applications in medium-voltage cables. The nanocomposites were prepared by incorporating Co₃O₄ nanoparticles and varying concentrations of CNTs (0, 0.1, 0.15, 0.20, and 0.25% by weight) into a PVC matrix. The UV–Vis spectroscopy revealed an absorption edge of 3.75 eV, a direct bandgap of 5.15 eV, an Urbach tail energy of 0.4594 eV, and a carbon cluster parameter of 44.617 for the PVC/Co₃O₄ + 0.25% CNT nanocomposite film. Incorporating CNTs enhanced the AC conductivity, dielectric constant, and dielectric loss compared to the pure Co₃O₄ sample. The highest AC conductivity (7.46 × 10^–4 S/m) was achieved for the PVC/Co₃O₄ + 0.25% CNT nanocomposite. COMSOL Multiphysics simulations were performed to study the electric field distribution in medium-voltage cables made of PVC and PVC/Co₃O₄ + 0.25% CNT nanocomposites. The simulations revealed a more uniform electric field distribution in the nanocomposite cable than the pure PVC cable, owing to Co₃O₄ nanoparticles and CNTs. The novelty of this study is improved uniformity in the electric field distribution for medium-voltage cable applications.

United Nations sustainable development goals (SDGs) are mended for the betterment of all living species on this earth. Climate change planning consistently revolves around sustainable products derived from natural raw materials. Our recent research has specifically targeted the optimization of biocatalyst production and microorganism growth through solid-state fermentation. In this research work, we utilized Aspergillus niger [S1], isolated from a mixed vegetable pickle. Initially, batch tests were conducted, altering the concentrations of five ingredients—sucrose, molasses, yeast extract, sunflower oil, and Tween-80 to achieve maximum extracellular biocatalyst (Lipases) production. Maximum extracellular biocatalyst activity was achieved in the presence of sucrose, molasses, yeast extract, sunflower oil and tween-80 at the rate of 6.39 ± 1.73^a U/mL, 2.2 ± 1.09^a U/mL, 2.22 ± 0.48^a U/mL, 3.06 ± 1.27^a U/mL and 2 ± 0.87^a U/mL respectively using different concentration of 1 g/L, 4 g/L, 0.5 g/L, 3.5% v/v and 1% v/v respectively through one factor at a time approach. Response surface methodology was employed to examine the interaction of critical medium components and their impact on biocatalyst activity. The range and level of selected independent variables were explored using the Box-Behnken experimental design. The maximum production was observed at the 6th run, reaching 13.0 U/mL by using combination of various critical medium components i.e., sucrose 3 g/L, molasses 5 g/L, yeast extract 1.5 g/L, sunflower oil 2.25% v/v, and Tween-80 0.5% v/v. Regarding the basal quantity of substrate, 10 g of mustard meal was also utilized.

This work aims to investigate the combustion characteristics, kinetics triplets, and thermodynamic parameters of microporous triazine-based organic polymers. The polymers were prepared by the incorporation of aliphatic and aromatic diamines (e.g., 1,4-hexane diamine (Hex) and 1,4-phenylenediamine (Bz)) with triazine core (Tr) via polycondensation polymerization. Both polymers Tr–Hex-diamine and Tr–Bz-diamine are microporous with a surface area of 212 and 524 m²/g, respectively. The successful synthesis was confirmed from FTIR and solid-state ¹³C CP-MAS. The combustion index (SN), kinetic triplets, apparent activation energy (Ea), pre-exponential factor (A), and thermodynamic parameters were estimated from the thermal degradation profiles of the polymers (TGA) at different heating rates. At the maximum heating rate (20 °C/min) the SN of Tr–Bz-diamine is 2.08, while it reached 4.2 for Tr–Hex-diamine, which indicates the high rate of combustion of the aliphatic hexyl chains. The other kinetic and thermodynamic parameters were determined by applying model-free isoconversional methods including Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (OFW), and Kissinger. From KAS, the average Ea for Tr–Bz-diamine and Tr–Hex-diamine are 163.4 and 147.8 kJ/mol, while 169.2 and 151.7 kJ/mol from OFW calculations. These values are higher in the case of the Kissinger method. The degradation mechanism and the rate of decomposition were determined from the Coats–Redfern method and by applying the master plot methods. Comparing the Ea values of the CR method with the integral method shows the possibility of the chemical reaction F3 mechanism beside multiple parallel reactions as shown by the master plot. The pre-exponential factor (A) along with the thermodynamic parameters (e.g., heat of enthalpy, entropy, and Gibbs free energy) were also determined and found to be within the same range of all methods.

Bacterial nanocellulose (BNC) currently has emerged as a potential biopolymer that can be used for various industrial applications. However, the major concern is the limitation of the bacteria used for BNC production on a larger scale. This study aimed to isolate and identify potential nanocellulose-producing bacteria from pineapple wastes. In this study, 11 isolates were screened and the F1 isolate, which produced the highest BNC yield was chosen for 16S rRNA sequencing. Based on the 16S rRNA analysis, Comamonas terrae YSZ sp. (OQ592726.1) was the best BNC producer with 1.68 ± 0.19 g/L yield. The physicochemical characteristics from FESEM analysis revealed that C. terrae YSZ sp. produced amorphous BNC, with fewer nanofibrils. The XRD analysis showed that the BNC produced had a 19.3% of crystallinity index. To the best of our knowledge, this is the first work reporting the isolation of C. terrae YSZ sp. from pineapple wastes with more amorphous regions providing an interesting alternative for heavy metal removal potentials.

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Heavy metal removal from wastewater has emerged as a major environmental concern on a global scale. The primary objective of this study was to determine how well lead (Pb) can be removed from wastewater by adsorptive processes using a chitosan-oligosaccharide-based hybrid (chitosan oligosaccharide (COS)/carboxymethyl starch binary blend material developed in the presence of glutaraldehyde (Glu). The amine and hydroxyl groups in the COS structure, the hydroxy and carboxy groups in the carboxymethyl starch, and the imine groups created when the amino group of COS reacts with the aldehydic group glutaraldehyde aid in the removal of Pb ions. FTIR, SEM, and X-ray diffraction were used to characterize the COS/CMC + Glu blend. Batch adsorption experiments, in which various factors including the impact of initial concentration, the dose of adsorbent, and the duration of contact, were used to analyze the removal of ions. The pH-dependent adsorption of Pb ions peaked at pH 5. The favorability of the reported experimental data was confirmed using various theoretical models, such as the Freundlich, the Langmuir isotherms, and pseudo-first- and pseudo-second-order kinetics. Adsorption was best fit by the pseudo-second-order and Langmuir isotherms.

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Water contamination is one of the biggest environmental issues the world is currently experiencing, and it is a result of growing industry and urbanization. The main causes of contaminated water are the textile industry and the colours included in waste effluent. The production of polymeric ferrite composites is the focus of this investigation. To the best of our knowledge these combinations of polymer and ferrites have not been synthesized before. The purpose of using these polymeric ferrite composites was to eliminate the artificially reactive Orange-122 dye from aqueous solutions. Various factors were optimized to get the best clearance, including pH (2–12), composite dose (0.01–0.3 g), contact time (10–120 min), temperature, and beginning dye concentration (20–200 mg/L). The acidic range (2–5) was shown to have the maximum dye removal of reactive dye, and the ideal composite dose was found to be 0.03 g/50 mL. Within the first sixty to ninety minutes, balance was reached. At 120–150 mg L^–1, the maximum level of reactive dye clearance was attained. As the temperature was raised, the chosen dye was more effectively removed, indicating that the process was endothermic. Various models, including thermodynamic, kinetic, and equilibrium models, were used to verify.