Volume 44, Issue 4

Structurally novel fluorinated polyurethaneimide (PUI) electro-optic polymer based on chromophore molecule b , diisocyanate MDI and anhydride BPAFDA was synthesized by stepwise polymerization of oligomer PUI with fluorinated aromatic diamines BATB and BATPP. Electro-optic (EO) PUI chain structure had the structure of polyimide and polyurethane chain segments, integrating the advantages of polyimide and polyurethane. The PUI possessed good film-forming property, a high glass transition temperature ( T g = 193 °C) and good thermal stability (5 % weight loss temperature T d up to 320 °C). Y-Structured inverted ridge polymer optical waveguides were designed and fabricated using the PUI as the waveguide core material. The PUI had good optical performance with an EO coefficient (γ 33 ) of 79 pm/V and 1.1 dB/cm optical propagation loss at a wavelength of 1550 nm. The results showed that the synthesized PUI met the performance requirements for the preparation of polymer optical waveguide devices and was suitable as a polymer electro-optic waveguide material.

Polyvinyl alcohol (PVA)-based scaffold fabricated by fused deposition modeling (FDM) shows great potential in cartilage repair field. However, the limited mechanical properties after being swollen by water molecules in the body fluid hinder their applications. Herein, the boric acid is introduced to improve the mechanical behaviors of FDM-printed PVA-based scaffold. The ICP, FTIR, SEM, and swelling behaviors are utilized to explore the influence of boric acid concentration on the materials. The results indicate that the boric acid would form boronic ester-crosslinked PVA (B-PVA) and the density of the crosslink will increase at first then decrease with the boric acid concentration increases. As the concentration of boric acid is 1 %, the densest crosslink point in materials can be obtained. Then the fatigue, relaxation, and creep behaviors tests are carried out, which indicates that the crosslinking will improve the mechanical behaviors of scaffold at a great level. At last, the scaffold shows a good mineralization ability and excellent biocompatibility.

This research focuses on the preparation of poly (3-hydroxy butyrate) (PHB) nanocomposites using the melt mixing method. Two types of organically modified nanoclay, Cloisite 93A (C93A), and Cloisite 30B (C30B), were incorporated at various weight percentages into the PHB matrix to create the nanocomposites. Comparative analyses were conducted between PHB/C93A and PHB/C30B to assess their tensile and impact properties in relation to the matrix polymer. Between the nanocomposites, the PHB/C93A nanocomposites shows an optimum tensile modulus of 949 Mpa with a 3 wt% clay loading, while PHB/C30B nanocomposites demonstrated improved percentage elongation at break of 5.33 % and enhanced Izod impact strength of 39.67 J/m at 3 wt% of clay load. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) signifies the thermal behavior of both the matrix and nanocomposite. The degree of crystallinity is observed to be 47 % in case of the PHB/C30B nanocomposites as compared to the PHB/C93A nanocomposites as 38 %. Again in case of thermogravimetric analysis (TGA), the maximum % char of 5.198 is observed for the PHB/C30B nanocomposites. The enhanced viscoelastic behavior of the PHB/C93A nanocomposites was attributed at a peak of approx. 55–60 °C due to the incorporation of C93A nanoclay into the matrix in the study of dynamic mechanical analysis (DMA). The morphological investigation using WAXD analysis showcased particle clay intercalation and dispersion within the PHB matrix, indicating effective clay-matrix interactions. Overall, this study sheds light on the enhanced properties of PHB nanocomposites with the incorporation of organoclay, offering potential applications in various industries.

The exploration of natural fillers has garnered considerable attention in response to persistent concerns about material pollution and diminishing resources. In the context of this study, one such natural filler under scrutiny is mango shell powder (MSP), a byproduct derived from mango processing. The central objective of this investigation is to assess the potential of MSP as a filler in flax-jute hybrid epoxy composites, with a keen focus on enhancing their properties. Specifically, the study aims to elucidate the impact of incorporating MSP filler on the mechanical and wear characteristics of these composites. The experimental approach involved the preparation of composite samples with varying weight percentages of MSP filler, ranging from 1 % to 9 % (1 %, 3 %, 5 %, 7 %, and 9 %), while maintaining a constant fiber and matrix weight ratio. The results obtained from the experiments revealed that composite samples containing a 7 % filler exhibited superior mechanical properties, while wear resistance demonstrated a noticeable decrease with the progressive increase in filler content. These findings suggest the potential efficacy of MSP as a filler in enhancing both the mechanical and wear characteristics of flax-jute hybrid epoxy composites, providing valuable insights for further applications in sustainable composite materials.

One of the biggest problems facing medical science today is preventing viral outbreaks, which highlights the significance of research initiatives aimed at creating antimicrobial coatings for a range of products, including textiles, medical devices, and public spaces. In this study, we aimed to determine the possible antiviral effects of polyethylene glycol (PEG) coating on feline coronavirus (FCoV). The PEG coatings were synthesized by a simple mixing method with a water-based acrylic binder in different weight percentages (3, 5, 10, 15, 20, and 25 wt%). The Spearman–Karber technique was used to calculate the viral titers, which were then expressed as the tissue culture infectious dose at 50 % CPE (TCID50/ml). 20 wt% PEG could result in a 3 log 10 reduction in virus titer with an inhibition rate of approximately 99.9 % against FCoV. The increment of PEG weight percent from 0 to 25 wt% decreases the hardness and glass transition temperature of the coatings from 38.1 to 5.5 HV and 15.45 to −15.48 °C. Apart from that, the wettability analysis has revealed that PEG coating is hydrophilic with water contact angle (WCA) of around 75 ± 0.5°–85 ± 0.5°. Adding 25 wt% of PEG makes the coating to be superhydrophilic with WCA of 39.85 ± 0.5°.

The urgent need for clean and affordable energy solutions to combat energy scarcity and global warming is paramount. Fuel cells, particularly microbial fuel cells (MFCs), offer a promising avenue for sustainable energy production. Proton exchange membranes (PEMs) are critical components in MFCs, but the high cost of Nafion, the gold standard PEM, poses a significant challenge. In this pioneering study, we tried to fabricate PEMs by crafting them from polymethyl methacrylate (PMMA), coupled with innovative combinations of potassium thiocyanate (KSCN) and citric acid. The synthesized membranes were studied for their water uptake capacity, ion exchange capacity and potential applications in MFC. The maximum remarkable water uptake capacities of up to 70 % for 10 % KSCN and 64 % for 7.5 % citric acid compositions was observed. Furthermore, these PEMs exhibit ion exchange capacities (IEC) ranging from 0.024 to an impressive 0.69 meq/gm, with the 7.5 % citric acid variant showcasing the highest IEC (0.69 meq/gm). The membranes having better IEC were applied to microbial fuel cell. This results in maximum power density of 50.03 μw/cm 2 , underscoring the tremendous potential these membranes hold as a cost-effective and environmentally friendly alternative to conventional PEMs in MFCs.

In this work, a non-isothermal viscoelastic computational framework is proposed for macroscopic polymer melt filling and mesoscopic spherulite growth. Firstly, the macroscopic viscoelastic governing equation is solved by coupled level set immersed boundary and finite-volume (LS-IB-FV) method. The melt-air interface is captured by the coupled level-set and volume-of-fluid (CLSVOF) method. And the mesoscopic crystallization behavior is predicted by the phase field model. Then, the numerical simulation for melt filling process is compared with experimental one to validate the coupled method. And it is simulated that the melt filling stage in a complex annular cavity with 17 small solid discs for the semi-crystalline polymer of isotactic polystyrene, and it is studied that the impacts of three different injection velocities on the flow modes, temperature distribution and solidified layers. Finally, in the regions of solidified layers, the growth of spherulites is simulated with/without melt flows at two different points. Numerical results show that the injection velocities can affect the flow modes and temperature distribution significantly. The morphology of polymer spherulite that is consistent with the experimental result can be observed clearly. With flow fields, the spherulites grow faster and densely towards the upstream direction.