Band 45, Heft 2

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–CH 2 Br group to the–N+(CH 3 ) 3 groups by new peaks. The composition and properties were analyzed to validate successful crosslinking and functionalization of the membrane.

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.

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.

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.

In this study, chitosan was first used as the raw material for filmmaking, and the film-forming conditions were optimized to prepare six kinds of chitosan-based membranes, and then charcoal composite membrane materials were prepared by adding different amounts of lignin charcoal to fill in the base membranes; the adsorption performance of the composite membrane was analyzed using H 2 S as the target, and the mechanical properties and structure of the composite membrane were explored using various testing techniques. The experimental results showed that the chitosan-based membrane could adsorb a certain amount of H 2 S due to its hydroxyl-rich surface. When lignin carbon was added to it, and with the increase of the content of lignin carbon, the performance of the membrane adsorption of H 2 S was improved, but the mechanical properties decreased, and in a comprehensive comparison of the adsorption performance and mechanical properties of the composite membrane, which had a better adsorption length of H 2 S adsorption of 84 min and the tensile strength of 1.65 MPa. The pore structure in the composite membrane due to microphase separation and the exposure of oxygen-containing functional groups on the surface of the base membrane and charcoal were the main reasons for the effective retention of H 2 S.

[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.

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.

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.