Lignite humic acid on reaction with formaldehyde and aqueous alkali led to a polybicyclo[3.3.1]nonane. This was characterized spectroscopically using mass spectrometry, FT-IR, powder X-ray diffraction, TEM, and NMR studies (1H-NMR, CP-MAS-SS-NMR) which though challenging were useful for confirming the structure of the BCN polymer. The product showed an envelope peak in its MALDI-MS spectrum, based on which M ̅ n , M ̅ w , and polydispersity index have been calculated. Based on the NMR spectrum of intermediate, the presence of the N-formyl group has been shown in it. The new polymer could be useful in agriculture in water-deficient areas. Most papers on humic acids include only broad and general information like elemental analysis (occasionally TEM, SEM, TGA, DSC, etc.). Very complicated structures have been proposed by scientists earlier. Only in very recent years, it has been recognized that these are relatively small molecules which masquerade as supramolecular structures. It is pointed out that most papers do not put down the structure of the compound and provide no concrete proof for proposing such structures. The novelty of our work is that we have characterized the precise molecular weights based on mass spectrometry and NMR spectroscopy along with a well-defined structure. This is not the case in most other publications.

The creation of nanostructured materials with a triply periodic minimal surface (TPMS), defined as a zero mean curvature surface having periodicity in three-dimensional space, is an emerging solution to optimize transport (i.e., the ion-conductivity and hydraulic permeability) through the next-generation of electrolyte and ultrafiltration (UF) membranes. Here, we used an amphiphilic ABC-type block copolymer (BCP) (namely, polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) (PS-b-P2VP-b-PEO)) to generate symmetric thick films (~8 μm) composed entirely of a TPMS-based structure, consisting of a PS matrix with a double gyroid (DG) minimal surface and hydrophilic stimuli-responsive (P2VP/PEO) nanochannels. To produce the core/shell DG-structured monoliths, we used a process combining the nonsolvent-induced phase separation (NIPS) process with a solvent vapor annealing (SVA) treatment. From such symmetric ABC-type BCP-thick films generated by NIPS-SVA, a mean hydraulic permeability as high as 514 L h-1 m-2 bar-1 was measured. This mean value was revealed to be nearly equal to that of asymmetric PS-b-P2VP-b-PEO membranes manufactured by NIPS, which have a substructure with an implicit irregular and random distribution of the internal pore structure and a skin layer with P2VP/PEO nanopores arranged into a hexagonal array.

In the current investigation, the mechanical properties of epoxy composites reinforced with banana pseudostem fibres, specifically focusing on tensile and impact behaviour, are investigated. The manufacturing process employed the meticulous hand-lay-up technique to fabricate six distinct samples. These samples included various combinations of short and woven banana fibres, treated and untreated, as well as a hybrid configuration involving layers of woven and short fibres. A fixed weight ratio of 60% fibres to 40% epoxy matrix was maintained for consistency. To ensure optimal material integrity, a careful application of resin and hardener in a 10 : 1 weight ratio was layered, with each addition of fibre followed by thorough rolling to eliminate any potential bubbles. The density and void fraction of the resulting composites were meticulously assessed to gauge the influence of this layering approach. Additionally, an X-ray diffraction (XRD) analysis was conducted to ascertain the impact of the chemical treatment on the cellulose content of the fibres. Our findings revealed that the tensile and impact properties were notably superior in the woven fibre composites. In particular, the chemically treated woven banana fibre epoxy composite displayed impressive values of 64.95 MPa for tensile strength and 24.37 KJ/m2 for impact strength. To gain deeper insights into the structure-property relationship, test specimens were analyzed using scanning electron micrographs. Lastly, comparative analysis by mapping the tensile properties from our present work with those from existing studies was carried out.

Agriculture and textiles have the highest production yields among all sectors to meet mankind’s basic needs, i.e., feeding and clothing; however, they are top contributors to environmental pollution and global waste generation. Their wastes and byproducts are precious organic materials, they have great potential as raw materials for the manufacturing of valuable products. This review sheds light on various textile and agricultural wastes, waste management issues, and their existing utilization. Current waste processing methods are mostly based on waste-to-energy routes or material reclamation; however, both methods are hazardous for the environment and are inefficient. During the past decade, many researchers have utilized agriculture and textile wastes in the fabrication of composites. Textile and agricultural wastes and byproducts can be efficiently used for composite fabrication and can be suitable alternatives to existing raw materials. Using textiles and agricultural wastes for composite manufacturing can not only address waste management issues and replace non-eco-friendly materials in the composite industry but also significantly improve composite properties.

Leather processing generates a huge amount of chromium (Cr) containing wastes, and one of them is chrome shavings (CS), which frequently end up in landfills. It may be harmful to the environment and human health due to the oxidation of Cr(III) to poisonous Cr(VI). Herein, CS and polyvinyl alcohol (PVA) are used for the preparation of flexible CS-PVA composite sheets, using CS as a skeletal and PVA as a cross-linker by a simple and facile technique. CS-PVA composite sheets are characterized by FT-IR, SEM, STA, and UTM. FT-IR analysis of CS-PVA composite sheets indicated the existence of dominating peaks corresponding to collagen amide bands as well as PVA characteristic bands, and it demonstrates the uniformity of the developed composite sheets. When the amount of PVA is increased, the tensile strength of CS-PVA composite sheets increases from 0.21 to 4.17 N/mm2. With increasing of the amount of PVA, the softness decreases from 6.47 to 3.7 mm, and SEM shows decreasing of pores in the composite sheet. The addition of more PVA makes CS-PVA composite sheets more thermally stable. This facile method of preparing CS-PVA composite sheet is low-cost and eco-friendly, having potential applications in various fields, including clothing, leather goods, decoration, packaging, and footwear products, as well as presenting promising platforms for effective utilization of industrial waste materials.

The search for alternative solutions for sustainable management of faecal sludge in the area of dewatering with biocoagulants/bioflocculants remains unfulfilled. Some available and accessible indigenous plants in the northern part of Ghana have been characterised and subsequently evaluated in their suitability for use as biocoagulant/bioflocculants. The Yila (Crossopteryx febrifuga) and the Voulo (Grewia mollis) plants were the indigenous plants used in this study. Three applications from the Yila wooden stem, the Yila bark, and the Voulo at different treatment concentrations with faecal sludge were monitored. The Yila wooden stem gave a potential of pollutant removal up to about 83.99%, 93.79%, and 91.54% for Chemical Oxygen Demand (COD), Total Suspended Solids (TSS), and turbidity, respectively. Application of the Yila bark gave a respective removal efficiency of up to about 77.39%, 82.02%, and 54.60% for COD, TSS, and turbidity. The efficiency of the Voulo plant obtained for COD, TSS, and turbidity was up to about 80.43%, 86.83%, and 72.55%, respectively. No cyanogenic or toxic compounds were identified in the characterised raw materials used for this study. The study has revealed the potential of producing biocoagulants that can perform as effectively as synthetic/chemical coagulants using locally natural raw materials but the use of it at large scale will only be applicable for batch or semi-batch systems. Some interesting constituents identified in the plants under consideration, such as trialkyl bismuthine and furan derivative, can open up opportunities to elucidate the potential applications of these identified plants in the areas of pharmaceuticals, cosmetics, glass and ceramics, rubber production, and other applicable medicinal advantageous areas.

Plastics are ubiquitous in our daily life. However, the use of petrochemical-based plastic as packaging materials causes the depletion of non-renewable resources, thereby leading to an increase in oil prices and economic crises. Moreover, these petrochemical plastics raise the issue of environmental pollution due to their non-biodegradability. Owing to this, there is a need to develop an alternative biodegradable and eco-friendly packing material. Agar, which is extracted from seaweeds, is one of the abundantly available polymers. However, moderate tensile strength and thermal stability restrict its application. As a step forward, agar/reduced graphene oxide (RGO) composites were prepared by in situ reduction of GO in the polymer matrix. The tensile strength of the composite was found to increase by 55% at 2% RGO loading. The electrical conductivity and thermal properties of the composite were also improved. The presence of conductivity suggested that apart from packaging, agar/RGO composites can also have potential applications as capacitor plates creating a supercapacitor and as electric field-induced wound healing material.

A sustainable approach to composites is leading to the use of natural fibers rather than synthetic materials, like carbon or glass, for reinforcement. However, the higher moisture absorption of natural fibers impairs the composite’s mechanical properties. Therefore, to improve the mechanical properties, some chemical treatments like silane and fluorocarbon can be performed to reduce the moisture absorption of natural fibers. In this study, flax was used as reinforcement, and epoxy was used as a matrix. In the first part of the study, flax reinforcement was treated with different concentrations of silane (20, 40, and 60 g/L) and fluorocarbons (80, 100, and 120 g/L). Moisture regains (MRs), absorbency, and tensile strength were measured at reinforcement levels. According to the results, reinforcements treated with 60 g/L silane (S3) and 120 g/L fluorocarbons (F3) exhibited the lowest MR values of 7.09% and 3.06%, respectively, whereas water absorbency was significantly reduced. The sample treated with 120 g/L fluorocarbons required 300 seconds extra time to absorb the water as compared with the untreated sample, whereas samples S3 and F3 showed an increase in tensile strength by 20.16% and 34.80% when compared with untreated reinforcement flax reinforcement. In the second part of the study, untreated and treated flax reinforcements were combined with an epoxy matrix for composite fabrication. MR and mechanical tests (tensile, flexural, and Charpy impact tests) were performed. Results revealed that treated flax-reinforced composites exhibited lower MR values 0.86% for F3 and 0.42% for S3, respectively. The tensile, flexural, and pendulum impact strengths of silane-treated reinforced composite sample C.S3 were increased by 15.07%, 117%, and 20.01%, respectively, compared with untreated reinforced composite samples. Consequently, both chemical treatments improve composite mechanical performance as well as service life.

Chitosan is a natural polymer derived from the deacetylation of chitin. It is mainly derived from crustaceans and fungal sources. It has many intrinsic properties, such as biocompatibility, biodegradability, cationic nature, and nontoxicity. These features of chitosan have made it an attractive material for various applications. Furthermore, these unique properties have found significant biomedical applications, such as in drug delivery, tissue engineering, antimicrobial agent, and wound healing. However, it has its drawbacks, such as the raw material source being seasonal and localized, the extraction procedure being time-consuming, costly, and involving the use of harsh chemicals in substantial amounts, and the quality of chitosan obtained from marine sources being variable. Furthermore, studies are needed to increase the yield and utilization of chitosan for various industrial purposes. Technological improvements, such as gene modification will enhance the yield and application of chitosan. This review focuses primarily on the numerous applications of chitosan in the biomedical field, including tissue engineering, wound dressing, drug delivery, and others.