Polymer International最新文献

Now that well-ordered nanoparticles can yield a promising performance in various fields, spatially regular arrangement of particles is a key requirement for nanoparticle-embedded engineering materials and devices. Here, we demonstrate a feasible, robust method where nanoparticles can be regularly distributed and encapsulated. Polymeric substrates with different sized nanoholes were injection-molded by controlling mold-wall temperature in a spatial and temporal manner. A hybrid structure of nanoparticles was constructed by binding quantum dots with metal nanoparticles, and they were filled into the nanoholes using the knife coating process. The morphology of the nanostructure prepared via the molding process and the nanoparticle array was analyzed using a scanning electron microscope and a transmission electron microscope. Fluorescence emission of the hybrid nanostructure was measured. The finding showed that the strategic approach introduced in this study could allow fabrication of hybrid nanoparticle structures with good processability and productivity. © 2024 Society of Chemical Industry.

Chitosan (CS)-based films incorporated with ethyl p-methoxycinnamate (EPMC) isolated from Kaempferia galanga L. were fabricated to prolong the shelf life of refrigerated pork. Addition of EPMC into CS-based films significantly improved the physical properties, such as opacity (6.42 to 46.33), moisture content (44.01% to 33.29%) and water vapor permeation (0.21 to 0.13 g mm kPa⁻¹ h⁻¹ m⁻²). These changes were verified via multiple spectral techniques, indicating that the improvement in the characteristics of the composite films probably resulted from the intermolecular interaction between CS and EPMC. The diameter of the inhibition zone against Escherichia coli of the composite film with a high content (0.4%) of EPMC increased from 1.42 cm in the control CS group to 1.93 cm. The pH values, thiobarbituric acid-reactive substances, total volatile base nitrogen and total viable count of bacteria of fresh pork stored at 4 °C for 8 days coated in composite film with a high content (0.4%) of EPMC were 5.8, 0.66 mg kg⁻¹, 20 mg (100 g)⁻¹ and 10⁶ CFU g⁻¹, respectively. This indicates that shelf life of fresh pork coated in the composite film was prolonged up to 8 days at 4 °C. The results demonstrated the considerable potential for the utilization of the composite film in pork preservation. © 2024 Society of Chemical Industry.

Incorporation of shape memory polymers into biomedical devices is an attractive option due to their notable advantages of low cost, biocompatibility, tunable degradability, patient-specific design and adjustable mechanical and thermal properties. Shape memory polyurethanes are particularly attractive due to their extensive temperature range for shape recovery as well as the ability to fine-tune the glass transition temperature. This study aimed to synthesize a shape memory polyurethane using glycerol as chain extender with a glass transition temperature within a suitable temperature range for biomedical applications. The results showed that the triggering temperatures for the synthesized samples change between 63.95 °C and 88.21 °C. Shape memory properties were investigated for the temperature range 40–75 °C. Shape recovery times were found to be substantial with increasing temperature with ~102 s at 40 °C and ~1 s at 75 °C. Shape fixity and shape recovery rates for the same temperature ranges were 77.8% and 85.6% at 40 °C and 100% and 100% for 75 °C. The cytotoxicity assay indicates promising biocompatibility of the synthesized material for biomedical purposes. Overall, the synthesized polymers were found to be a potential candidate for biomedical applications such as stents, aneurysm filling or occlusion devices. © 2024 Society of Chemical Industry.

A set of ionic cryogels based on the biocompatible zwitterionic polyelectrolyte N-(3-sulfopropyl)-N-(methacryloxyethyl)-N,N-dimethylammonium betaine and a second comonomer of a different nature (from the class of acrylates, acetates or sulfonic acids) is successfully synthesized. The variation of the nature of the comonomer used allows a material to be obtained with controlled pore sizes and hierarchical porosity as proved by SEM, optical microscopy and N₂ adsorption–desorption experiments. The compositions of cryogels with good adhesive properties to the electrode, as well as effective ion exchange during an electrochemical reaction inside the cryogels, which is shown by reversible copper recharge processes after doping a cryogel with copper ions, are determined. Thus, cryogels that meet the primary requirements for a material for use as polymer electrolytes for batteries are synthesized and characterized. © 2024 Society of Chemical Industry.

Two new kinds of modified bifunctional and trifunctional guaiacol, namely 4,4′-(bis(4-fluorophenyl)methylene)bis(2-methoxyphenol) (BBM) and 4,4′-((2-hydroxy-4-methoxyphenyl)(phenyl)methylene)bis(2-methoxyphenol) (HBM), were synthesized using guaiacol with respective keto derivatives under appropriate experimental conditions. Two series of benzoxazines were developed with BBM and HBM using various amines (dodecylamine (dda), octadecylamine (oda), furfurylamine (ffa), aniline (a) and 4-fluoroaniline (fa)) with paraformaldehyde through Mannich condensation with a view to utilize them for anticorrosive and optical resistant coating applications. The molecular structures of the synthesized precursors and benzoxazine monomers were characterized using appropriate analytical techniques. The polymerization temperature of the benzoxazines was assessed using differential scanning calorimetry. Among the benzoxazine monomers synthesized, the monomer HBM-fa exhibits the lowest curing temperature (217 °C). Data obtained from thermogravimetric analysis indicated that the polybenzoxazines poly(BBM-ffa) and poly(HBM-ffa) possess higher thermal stability (455 and 425 °C) and higher char yield (54% and 60%) than the other polybenzoxazines. In both series, octadecylamine-based polybenzoxazines (BBM-oda and HBM-oda) exhibited the highest values of water contact angle of 148° and 149° respectively. Additionally, the benzoxazines showed aggregation-induced emission properties during fluorescence studies. Morphological analyses using different analytical techniques on selected polybenzoxazines were carried out before and after the corrosion process. Results from corrosion studies, i.e. Tafel and Nyquist plots, implied that the polybenzoxazines can be used as effective coating material to protect mild steels from corrosion. Data from different studies suggest that the developed benzoxazines can be used in the form of optical and anticorrosion coatings under thermally harsh and moist environments. © 2024 Society of Chemical Industry.

Conjugated microporous polymers (CMPs), distinguished by their extended π-conjugated backbones, nontoxicity and micropore characteristics, provide notable benefits in the development of heterogeneous catalysis systems for task-specific transformations. This review aims to summarize the up-to-date advances in the field of photocatalysis by CMPs, with a particular focus on the applications of CMPs in photocatalytic hydrogen precipitation, pollutant degradation and organic transformation in the last 5 years. Meanwhile, this review also summarizes the major challenges in this field and gives suggestions for the feasible direction of development. © 2024 Society of Chemical Industry.

In view of the huge potential in various applications, biopolymer-based polyurethane foams (PUF) are attracting researchers. In the present study, we report the modification of guar gum (GG) via polyaddition reaction with toluene diisocyanate (TDI) using dibutyltin dilaurate as catalyst, silicone oil as surfactant and calcium carbonate as filler to form GG-PUF. The as-synthesized GG-PUF was characterized by Fourier transform infrared (FTIR), XRD, field emission SEM, energy-dispersive X-ray spectroscopy, and surface charge analysis. In the FTIR spectrum of GG-PUF, peaks at 3290, 1705, 1595, and 1510 cm⁻¹ are attributed to stretching vibrations of –NH, –C=O, –C=C– of the benzene ring of TDI, and the –NH bending vibration of the urethane group, respectively. The XRD patterns of GG and GG-PUF indicate their semicrystalline and amorphous nature, respectively. The field emission SEM of GG-PUF exhibits high porosity compared to the smooth surface of GG due to the evolution of CO₂ gas during the foaming reaction. The GG-PUF was evaluated as an adsorbent for cationic dyes from wastewater. The preliminary adsorption studies showed maximum adsorption for malachite green with 93.54% removal at 40 °C and pH 6.0 in 60 min. The adsorption mechanism was studied by various nonlinear kinetic models, namely the pseudo-first order, pseudo-second order and Elovich, and nonlinear isotherm models, such as Langmuir, Freundlich and Temkin. The adsorption followed pseudo-secondorder kinetics and a Langmuir isotherm with a maximum adsorption capacity of 156.44 mg g⁻¹. The small value of the error function (χ²) and normalized standard deviation (Δq%) from nonlinear models indicated the better fitting of the data into nonlinear kinetics and isotherm models. Furthermore, GG-PUF showed substantial degradability under simulated wastewater conditions at acidic and alkaline pH and reusability up to 10 adsorption–desorption cycles. Hence, GG-PUF has tremendous potential as a sustainable, economical and environmentally friendly adsorbent for eliminating cationic dyes from wastewater. © 2024 Society of Chemical Industry.

The seawater desalination industry does not need exotic two-dimensional materials. However, it faces challenges in terms of membrane resilience to stressors such as temperature and oxidation and especially in the area of (bio)fouling. Membrane replacement is a large part of the operating expenditure of modern desalination plants and anything that increases the effective lifespan of a membrane will have economic impact. There are also emerging requirements for membrane selectivity, especially in desalination-adjacent brine-valorisation activities. These challenges provide abundant scope for the exercise of creativity by polymer scientists. © 2024 Society of Chemical Industry.

The precipitation technique was used to prepare calcium hydroxyapatite pectin (CaHAp-Pec) and calcium hydroxyapatite xanthan (CaHAp-Xan) hybrid materials. Chemical analysis, XRD, Fourier transform infrared spectroscopy, specific surface area, TGA and SEM were used to analyze the materials and the organic–inorganic interfaces. XRD and SEM investigations demonstrated that the presence of the biopolymer had an impact on both the structural and morphological properties as well as the crystallinity. The PO₄³⁻ vibration modes are visible in the IR spectra, and new vibration modes mostly associated with Xan and Pec are observed at 1594, 2878 and 3246 cm⁻¹. The specific surface area values were reduced after the chemical functionalization of CaHAp with pectin and xanthan gum. The ability of the three materials CaHAp, CaHAp-Pec and CaHAp-Xan to sorb methylene blue from aqueous solutions was assessed. The adsorption kinetics results best fitted the pseudo-second-order model. The isotherm data agreed well with the Freundlich model. The adsorption capacity values of porous composites CaHAp-Xan 5%, CaHAp-Pec 10% and CaHAp reached 277, 243 and 144 mg g⁻¹, respectively. The non-spontaneous and exothermic nature of the adsorption was demonstrated by the thermodynamic parameters (ΔG⁰, ΔH⁰ and ΔS⁰). Adsorption results confirmed that CaHAp-Xan could be used as an effective adsorbent of cationic dyes from water. © 2024 Society of Chemical Industry.

The use of hybrid fillers provides a new route for improving the friction and wear properties of polymer composites due to their synergistic effect. In the present study, a two-dimensional derivative of MAX phases (MXene) was loaded onto the surface of carbon fiber (CF) and used as reinforcement to modify the tribological properties of epoxy resin (EP) composites. The latter were tested on a plate-on-ring contact configuration as a function of load and sliding speed with reference to composites filled with single carboxyl-terminated butadiene acrylonitrile (CTBN), MXene and CF. It was revealed that, when MXene and CF were incorporated simultaneously into EP/CTBN, the composite's friction coefficient and wear rate were reduced by 55.8% and 96.6% compared to those of EP/CTBN matrix. The mechanisms underlying this improvement are discussed based on a thorough analysis of the morphology of the worn surface and the chemical composition of transfer films. As a result, synergistic interaction between MX@CF and the rubber phase was revealed. © 2024 Society of Chemical Industry.