International Materials Reviews

Abstract A series of magnetorheological shear stiffening gels (MRSSGs) were produced by incorporating varying amounts of carbonyl iron powder (CIP) into a shear stiffening gel (SSG) matrix. The dynamic excellence of MRSSG was evaluated using a rheometer. MRSSGs possess magnetic-sensitive properties and can autonomously respond to external stimuli because of B–O cross-linked bonds. In examining the effect of angular frequency on the magneto-induced shear modulus, an initial angle was introduced, leading to the establishment of a diagonal and distributional particle chain model. This model serves to indirectly illustrate the relationship between the magneto-induced modulus and the shear angular frequency. Theoretical results of magneto-induced modulus, derived from modeling calculations and analyses, align well with experimental findings as magnetic induction intensity varies across different excitation angular frequencies. Additionally, the magneto-induced modulus exhibits an increase that gradually approaches saturation with rising magnetic induction intensity.

Abstract Blade coating is a technique where the fluid is applied to a surface using a fixed blade, providing economic advantages compared to other coating technologies. It is widely used in producing paper, preserving information, manufacturing photographic films and magnetic storage devices. This article examines the blade coating process using hyperbolic tangent model. With the help of mass and momentum conservation laws, the mathematical equations are obtained and then simplified using lubrication approximation theory (LAT). A well-known perturbation method is used to solve the resulting equation. The graphical results are produced for various values of blade height ratio (k) and Weissenberg number (We) on velocity, pressure and pressure gradient while the blade load is given in tabulated form. It is observed that both parameters k and We are responsible to increase velocity in plane and exponential coaters. It is also interesting to note that hyperbolic tangent model (We = 0.8) predicts 26.92 % lower pressure in comparison to Newtonian model at (x = 0.6706) in plane coater. Further, by increasing the value of k and We, the blade load declines in plane and exponential coaters.

Abstract To investigate the influence of AO 2246 and AO 4426 on the damping properties of polyvinyl alcohol/chlorinated polyethylene (PVA/CPE) composites, a series of composites were prepared by adding AO 4426 into PVA/CPE-AO 2246 under the constant mass ratio of hindered phenol in the composites. The dynamic mechanical properties and microstructure of materials were investigated by DMA, DSC, SEM, and FT-IR. The results showed that a new damping peak appeared near 50 °C by adding AO 4426, which indicated phase separation between AO 4426 and the matrix occurred. With the increase of AO 4426, the damping peaks in the low-temperature section were improved. The value of low-lying region between the double damping peaks, when the hindered phenol coexisted was higher than that of the composites containing only AO 4426, which indicated that the damping temperature domain of the composites was effectively broadened. At the melting temperature of AO 4426 microcrystalline and AO 2246 microcrystalline, no obvious peaks were observed simultaneously, indicating that the hindered phenols inhibited the crystallization of each other.

Abstract This project aims to develop a manufacturing method for a newly designed soft robot gripper in one shot by utilizing a low-viscosity liquid silicone rubber (LSR) lost-core injection molding embedded with a polyvinyl alcohol (PVA) water-soluble core inside. Due to the relatively high viscosity of LSR, higher injection pressures were needed to complete the mold-filling process. This, in turn, resulted in a washout of the PVA lost core. Therefore, this study used a lower viscosity of LSR and pressure to avoid this problem. Ansys structural analysis simulation was used to get the experiment variables and then compare them with the real experiment results. The maximum pressure employed in the simulation of the gripper bending is 30 kPa with 119.38 mm, while the experimental is 112.65 mm total deformation. Finally, the washout of the lost core, the bending restriction problem, and the complicated manufacturing problems in this area were tackled in this study. The design of a finger with a greater angle at the edge and the use of low-viscosity LSR as the primary material in a one-shot lost core LSR injection molding method are extensions from previous studies that are believed to be valuable inventions for academic and practical applications.

Abstract With the global attention on plastic pollution, polylactic acid (PLA) is quickly becoming an alternative to traditional plastics. The current pressing challenge now is to enhance the degradation rate of PLA while simultaneously reducing costs. We investigated the influence of reed fibers on the biodegradation of PLA-based composites under various environmental conditions. The crystallization behavior, surface morphology, and functional group changes of the samples during enzymatic degradation were analyzed using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared spectrometer (FTIR). The results indicate that reed fibers significantly increased the hydrophilicity of the composites and reduced the crystallinity of PLA, thereby enhancing the degradation rate of the composites. This rate increased with the higher concentration of reed fibers. The research results will provide a theoretical reference for the design of PLA composites that are better aligned with market demand, which is used to balance the requirements for degradation performance during product use and after disposal and expand the application of PLA/RF composites in the construction, agriculture, and packaging.

Abstract This work reports a method for preparing liquid metal/thermoplastic polyurethane (LM/TPU) elastic composite materials through melt blending, and enhancing the thermal conductivity of the composites using a rolling regulation process. Through observation of the microstructure of the composite material, it is found that the vane mixer can effectively disperse LM uniformly, which leads to a significant enhancement in thermal conductivity from 0.21 W m−1 K−1 of pure TPU to 2.12 W m−1 K−1 for composite with 50 vol % LM. After rolling regulation, SEM images reveal the formation of interconnected thermal conduction pathways within the composites. The thermal conductivity of the composite material with 30 vol % LM increases from 1.74 W m−1 K−1 to 2.50 W m−1 K−1, which is higher than the pre-regulation thermal conductivity of the composite with 50 vol % LM. Moreover, the thermal conductivity of the composite material with 50 vol % LM increases even further to 3.16 W m−1 K−1. The rheological behavior of the composite further substantiates the establishment of a network configuration after the rolling regulation that facilitates heat transfer. This implies that the melt blending-rolling regulation process can achieve the fabrication of composite materials with high thermal conductivity, offering a reliable strategy for industrial development of flexible thermal conductive materials.

Abstract Polymer electrolyte membrane-based water electrolysis technology is a productive method for converting electrical energy into hydrogen. To improve and optimize the performance of the water electrolytic system, an anion exchange membrane (AEM) water electrolyzer is an excellent choice. AEM possess inadequacies in cation structural design, and diversity in development approaches with each new cation inclusion. This study focuses on the synthesis and characterization of a variety of poly (2,6-dimethyl-1,4-phenylene oxide) (PPO)-based AEMs crosslinked with azonia-spiro undecane (ASU). The design process consists of three steps: first P-ASU making followed by quaternarization and then PPO bromination, followed by P-ASU and BPPO crosslinking. The membrane’s stability is enhanced by adding polyethylene glycol (PEG). PPO has outstanding mechanical and thermal stability, and its backbone can be functionalized through a variety of ways. Bromination was performed with quantitative control in this study. The developed membrane was examined using analytical tools (e.g., TGA, FTIR, HNMR, SEM). The results revealed that membrane demonstrated sufficient thermal stability between 150 °C and 250 °C as degradation phase. Characterization results also contribute to accurately measuring membrane surface morphology and stability at 4.38 ppm and 3.13–3.24 ppm transition from the–CH2Br group to the–N+(CH3)3 groups by new peaks. The composition and properties were analyzed to validate successful crosslinking and functionalization of the membrane.

Abstract In this work, an anti-collision beam was manufactured through a thermoplastic composite overmolding (TCO) process. This process includes thermoforming of continuous glass fiber reinforced thermoplastic composite (CGFR-PP) and overmolding of short glass fiber reinforced thermoplastic composite (SGFR-PP). Double cantilever beam (DCB) and end-notched flexure (ENF) tests were performed to obtain the interfacial bonding fracture toughness between CGFR-PP and SGFR-PP, which was then used to establish a cohesive zone model (CZM). A continuum damage model (CDM) based on Tsai-Wu criterion was established to simulate the damage behavior of CGFR-PP. Tensile and bending tests on CGFR-PP and single lap shear (SLS) tests were conducted to verify the validity of the CDM and CZM. At last, the finite element model was used to predict the bending properties of the anti-collision beam, and the error of maximum load is approximately 5 %. Results reveal that the simulation results demonstrated a good agreement with the experimentally obtained force-displacement curves in terms of stiffness and maximum load.

Abstract Bio-based PA5T/56 was successfully prepared by a self-developed and novel modulated polymerization on this condition when the relationship between temperature and pressure was strictly controlled during the process to render the reactivity ratio of each monomers basically the same. In this case, the obtained PA5T/56, with approximately alternating copolymerization structure, possesses better physical and chemical performance and melt flowing properties. Meanwhile, the real-time sampling and testing was operated during the process to get the experimental values of reactivity ratio. Furthermore, the chain growth process of the ternary polymerization reaction was also calculated and simulated by referring to the Mayo-Lewis formula as well as using the Monte Carlo method, and a probabilistic statistical treatment for estimating the reactivity ratio was given. Finally, by comparing the results, it could be found that the experimental values of the reactivity ratio in general accord in the calculated values with reference to the Mayo–Lewis formula and the simulated values of the mathematical model, the values of r 12 and r 13 are basically the same, which confirmed the successful synthesis of the bio-based PA5T/56 with approximately alternating copolymerization structure, and that the established mathematical model for estimating the reactivity ratio is relatively accurate and is applicable to the ternary polymerization.

Abstract Poly(l-lactide-co-caprolactone) (PLCL) is the polymeric material with good biodegradability and biocompatible properties, but it is insufficient in strength properties that the pure PLCL is performed as orthopedic bandage. The PLCL has been blended with the laponite which is modified by cetyltrimethylammonium bromide (CTAB) to prepare composited bandage splines. The organic-modified laponite (OM-laponite) results of Fourier transform infrared (FTIR) and thermogravimetry analysis (TG) indicate that the laponite was successfully grafted with CTAB and the thermal stability was improved with increasing CTAB. The mechanical properties reveal that elongation at break strengthen with the increasing OM-laponite. When the content of OM-laponite is 2.0 %, the elongation at break and tensile strength of composited spline are superior to the medical orthopedic bandage. The results of thermal stability show that it was helpful to improve the crystallization properties of PLCL with the addition of OM-laponite. The water contact angle results demonstrate that the hydrophilicity is enhanced and is beneficial to cell adhesion. The results of cell experiment illustrate that the composite materials have a certain effect on cell proliferation when the content of OM-laponite is less than 2 %. Compared with the medical orthopedic bandage, it is satisfied with the application requirements.

Abstract [2-(methacryloyloxy) ethyl] trimethylammonium chloride (MAETMAC) was grafted onto the casein backbone using the microwave-assisted technique. It was studied as a bio-based wood binding adhesive for fabrication of single standard lap joints. The hyper branched polymer network formed post grafting facilitated strong adhesion and enhanced the water holding capacity of the developed adhesive. The universal testing machine (UTM) was used to study the failure shear stress. The self-separation time for each grafted protein grade was reported as a study of water resistivity of the adhesive. The programmability of the properties – ‘failure shear stress’ and ‘self-separation time’ were controllable at the molecular level in terms of percentage grafting.

Abstract This study presents a quantitative assessment of cross-linked polyvinyl alcohol (PVA) granules as sensing elements for detecting aliphatic carboxylic acids and their sodium salts in aqueous solutions. Swelling kinetics were measured across solute concentrations ranging from 0.2 N to 1.0 N, with the granule radius varying between 0.31- and 0.43-mm. Results indicated that both carbon chain length and the presence of additional carboxyl groups exert a pronounced effect on the equilibrium swelling degree, thereby highlighting the interplay between hydrophobic interactions and hydrogen-bond formation. To interpret these observations, a heterophase physicomathematical model was employed, yielding three main kinetic coefficients (K1, K2, and K3) that capture solvent flux, polymer network elasticity, and solute transport. The model fits exhibited root-mean-square deviations below 1 %, attesting to its reliability in describing complex swelling - deswelling processes. Additionally, three-dimensional kinetic surfaces were constructed to illustrate how swelling evolves over time and concentration, revealing that initial swelling curves can serve as a rapid indicator of solute concentration. By leveraging the reversible nature of polymer swelling, this method offers a non-invasive, cost-effective approach suitable for monitoring organic acids in diverse fields such as environmental analysis, pharmaceutical processes, and chemical engineering.

Abstract Chitosan-based nanofibers loaded with therapeutic agents are promising for wound treatment but loading hydrophobic compounds remains challenging. To address the limitations of curcumin incorporation in chitosan/polyethylene oxide (CS/PEO) nanofibers, we developed a novel Pluronic-based micelle to encapsulate curcumin, followed by the incorporation of zinc oxide nanoparticles (ZnO-NPs) as an antibacterial agent to improve the performance of the wound dressings’ materials. We successfully fabricated CS/PEO scaffolds via electrospinning, incorporating curcumin-loaded micelles and synthesized ZnO-NPs. Comprehensive morphology characterization was performed using SEM, and the presence of ZnO-NPs and curcumin was verified by EDX and FT-IR spectroscopy. The developed nanofibers showed a slower release profile, with approximately 80 % of curcumin released into the aqueous medium within 24 h and appearing to progress to a steady state by five days. Notably, the nanofiber mats exhibited antibacterial activity against the Gram-positive bacterium Staphylococcus aureus, and supported fibroblast proliferation and attachment, indicating excellent biocompatibility. These findings suggest that the developed nanofiber scaffold, characterized by its controlled drug release, potent antibacterial properties, and biocompatibility, holds promise as an advanced wound dressing material.