Current Materials Science - Volume 16, Issue 4, 2023

Presently, scientists and researchers are in an endless quest to develop green, recyclable, and eco-friendly materials. Natural fibre reinforced polymer composites became popular among materialists due to their lightweight, high strength-to-weight ratio, and biodegradability. However, all-natural fibre reinforced polymer composites are not biodegradable. Polymer matrices like poly-lactic acid (PLA) and poly-butylene succinate (PBS) are biodegradable, whereas epoxy, polypropylene, and polystyrene are non-biodegradable polymer matrices. Besides biodegradability, PLA has been known for its excellent physical and mechanical properties. This review emphasises the mechanical properties (tensile, flexural, and impact strengths) of natural fibrereinforced PLA composites. Factors affecting the mechanical properties of PLA composites are also discussed. It also unveils research gaps from the previous literature, which shows that limited studies are reported based on modeling and prediction of mechanical properties of hybrid PLA composites reinforcing natural fibres like abaca, aloe vera, and bamboo fibres.

Nanofibers are a type of nanomaterial with a diameter ranging from ten to a few hundred nanometers with a high surface-to-volume ratio and porosity. They can build a network of high-porosity material with excellent connectivity within the pores, making them a preferred option for numerous applications. This review explores nanofibers from the synthesis techniques to fabricate nanofibers, with an emphasis on the technological applications of nanofibers like water and air filtration, photovoltaics, batteries and fuel cells, gas sensing, photocatalysis, and biomedical applications like wound dressing and drug delivery. The nanofiber production market has an expected compound annual growth rate (CAGR) of 6% and should reach around 26 million US $ in 2026. The limitations and potential opportunities for large-scale applications of nano-fibrous membranes are also discussed. We expect this review could provide enriched information to better understand Electrospun Polymer Nanofiber Technology and recent advances in this field.

Humans have been using plant-derived gums for a variety of purposes since the beginning of time. Gums and mucilages are common natural materials utilised in both traditional and innovative dosage forms. Natural polymers are found to be very effective after incorporation in novel dosage forms to fulfill specific roles, resulting in improvements in drug delivery by increasing the drug expulsion rate and absorption. Natural medicines and excipients are becoming increasingly popular worldwide because of their inert nature, less toxicity, cheap and biologically degradable, and ease of availability. Many patents like WO/2018/199924A1 and WO/2004/094443A1 have been published on the uses of gums and mucilages in pharmaceuticals. The plant-derived polymeric compounds (gums and mucilages) are discussed in this study, along with their application and reported research and patents on their utilization in innovative drug delivery methods.

Aim: Preparation of cerium containing silicious MCM-22 zeolite material and explore its application for biomass conversion. Background: Zeolites and zeolite like microporous materials are well known as potential heterogeneous acid catalysts, whose discovery has made a significant impact in the petroleum, petrochemical and fine chemical industries. In recent years, zeolite, zeolites like molecular sieves, and inorganic oxide-based heterogeneous catalysts played a significant role in biomass valorization to receive value-added chemicals. Thus we focused on utilization of zeolite for biomass transformation. Objective: Preparation of cerium containing aluminium-free siliceous MCM-22 (AF-CeMCM- 22) by the in-situ hydrothermal method and explore its importance on biomass transformation. Methods: Powder XRD, FTIR and BET surface area were used to study the microstructure of the samples. SEM and FE-SEM were used to study morphology, TGA was used to evaluate the thermal stability, and 29Si NMR and DR-UV-Vis were used to study the environment of the MCM-22 framework. The prepared and confirmed material was used for the oxidation of levulinic acid over the liquid phase setup. Gas chromatography was used to evaluate the catalytic study, such as conversion and selectivity; also, GCMS was used for the confirmation of products. Result: The powder XRD pattern showed well distinguish MCM-22 framework structure with a uniform dispersion of cerium ions in the MCM-22 framework. SEM image of the cerium AFCeMCM- 22 showed platelet structure having flaky spherical morphology and the surface area in the range of about 175 m²;g⁻¹. 29Si NMR and DR-UV-Vis studies confirmed the well-condensed nature of the MCM-22 silica framework and the cerium ions present in both tetrahedral and octahedral extra-framework environments. Conclusion: The catalyst developed in the present studies was found to be a promising catalyst for the conversion of iso-eugenol to vanillin at 60°C, using H2O2 oxidant with the vanillin selectivity of 71%.

Background: The primary hot rolling method implemented is differential speed rolling (DSR). The material is rolled and grains are strained, producing fine dynamic recrystallization (DRX) grains that improve material strength and ductility. Objective: The material introduced and under investigation in this paper is an Mg-based alloy, Mg5Zn (wt. %), whose microstructure is enhanced through a combination of heat treatments with proper temperature and holding time and subsequent plastic deformation through hot rolling to evaluate the effect on mechanical properties. Methods: The method involves preheating the material to various temperatures in a range from 250ºC to 350ºC and rolling to various thickness reductions to analyze the effect of single-pass differential speed rolling (DSR) and conventional rolling (CR) on the DRX process and its influence on mechanical properties. Results: The effect of single-pass differential speed rolling (DSR) and conventional rolling (CR) on the DRX process shows that the process produces increasing amounts of finer DRX grains at higher rolling reductions, thereby improving the strength and ductility of the material. Conclusion: This investigation demonstrated that single-pass DSR can improve the mechanical properties and formability of Mg5Zn more effectively than CR in terms of grain refinement analyzed through OM, SEM, and EBSD resulting in enhanced tensile strength and ductility.

Background: Tissue engineering is an emerging technology developed for the therapeutic reconstruction of damaged tissue. Objective: In this study, a ceramic/polymer nanocomposite bone tissue engineering scaffold was prepared by coating a tetracalcium phosphate/dicalcium phosphate mixture slurry on a porous 3D chitosan-gelatin construction. Methods: The phase composition, structural groups, and morphological aspects of the samples were characterized. Furthermore, the 3D composite scaffold was immersed in simulated body fluid (SBF) solution at 37ºC for various periods to track its compositional and structural changes. Results: Based on the results, the coated layer is composed of needle-like carbonated apatite nanosized crystals with some tetracalcium phosphate/dicalcium phosphate initial materials. The nanocomposite was porous with an average macropore size of about 410 μm. The in vitro tests revealed that the composition of the coated layer tends to be apatite crystals, which are similar to natural bone in terms of chemistry and morphology. Conclusion: The results suggest that a simple coating of chitosan-gelatin scaffolds using reactive calcium phosphate particles may introduce a novel nanocomposite scaffold with improved mechanical strength, bioactivity, and osteoconductivity.

Background: The titanium silicide Ti5Si3 possesses many desirable properties, such as a high melting point, excellent high-temperature oxidation resistance, low density, and relatively high hardness, and it is considered a promising structural intermetallic compound. However, like most ceramic materials, originating from low symmetry (D88) in its crystal structure, Ti5Si3 has poor fracture toughness and limited flexibility at room temperature, and at high temperatures, its creep resistance also drops sharply, which hinders its application. To overcome these shortcomings, it is suggested that TiC is a practical addition to Ti5Si3 to overcome the brittleness. Compared with monolithic Ti5Si3, Ti5Si3/TiC composites have a higher fracture toughness. Ti5Si3/TiC composites can be prepared by many ways, which commonly require high energy cost, complex processes and provide low efficiency. Therefore, the search for environmentally friendly strategies for the production of Ti5Si3/TiC is still ongoing. Objective: This article proves that we can successfully prepare Ti5Si3/TiC composites from CaTiO3/SiO2/C precursor by using SOM technology and explores the reaction mechanism of electrochemical process. Methods: In the process of electroreduction of CaTiO3/SiO2/C particles into Ti5Si3/TiC composites, we mainly used SOM technology at 1273 K and 4.0 V in molten CaCl2 and under an argon atmosphere. Results: The results show that the Ti5Si3/TiC composites can also be successfully electrosynthesized from CaTiO3/SiO2/C precursors by using SOM-based anode systems at 1273 K and 4.0 V in molten CaCl2. Conclusion: This work demonstrates that Ti5Si3/TiC composites have been successfully electrosynthesized from CaTiO3/SiO2/C precursors using SOM-based anode systems at 1273 K and 4.0 V in molten CaCl2. The Ti5Si3/TiC has a smooth surface and micro/nano-porous structure. The formation routes for Ti5Si3 and TiC are independent. In summary, the SOM-assisted controllable electroreduction process has the potential to provide a novel one-step route from CaTiO3/ SiO2/C precursors to Ti5Si3/TiC composites in molten salts.