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Osemeahon SA, Akinterinwa A, Fasina E, Andrew FP, Shagal MH, Kareem SA, Reuben U, Onyebuchi PU, Adelagun OR, Esenowo D. Reduction of polystyrene/polyurethane plastic wastes from the environment into binders for water-resistant emulsion paints. Heliyon 2024; 10:e27868. [PMID: 38533006 PMCID: PMC10963325 DOI: 10.1016/j.heliyon.2024.e27868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 02/08/2024] [Accepted: 03/07/2024] [Indexed: 03/28/2024] Open
Abstract
Waste management is fundamental to resource and environmental sustainability. Expanded polystyrene (EPS) and polyurethane (PU) waste plastics were recycled and applied as binder in emulsion paint formulation. The recycled polystyrene (rPS) and polyurethane (rPU) were blended into composite resins, where toluene was used as the solvent. The blends of rPS and rPU were optimized, while some physicochemical properties of the composite blends (rPS/PU) were evaluated. The results showed that the incorporation of rPU into rPS increased the viscosity (1818 mPa-3924 mPa), rate of gelation (dry-to-touch time: 15 min-0.25 min), moisture content (2.7%-8.1%), moisture uptake (3.2%-5.0%), solid content (48%-53.4%) and density (0.82 g/cm3 to 1.050.82 g/cm3) of the rPS/PU composite resins. Characterization was carried out using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and atomic force microscopy (AFM). The results summarily showed that there are interactions among the rPS and rPU molecules in the composite, where complimentary structural and morphological characteristics were also achieved. The composite resin also exhibited superior bond strength (0.5-4.24 Mpa) on wood, cast mortar, ceramic, and steel surfaces due to its stronger intra- and inter-surface interactions compared to the neat rPS resin. The composite resin was used as a binder in the formulation of emulsion paint. The paint exhibited stronger resistance to water, among other superior properties, when compared to the paints formulated using neat rPS and conventional polyvinyl acetate (PVA) resins. The reduction of plastic waste in this study holds potential for the production of highly water-resistant emulsion paint for outdoor and indoor applications.
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Affiliation(s)
| | | | - Esther Fasina
- Department of Chemistry, Modibbo Adama University, PMB 2076, Yola, Nigeria
| | - Fartisincha P. Andrew
- Department of Science Laboratory Technology, Modibbo Adama University, PMB 2076, Yola, Nigeria
| | - Muhammed H. Shagal
- Department of Chemistry, Modibbo Adama University, PMB 2076, Yola, Nigeria
| | - Semiu A. Kareem
- Department of Chemical Engineering, Modibbo Adama University, PMB 2076, Yola, Nigeria
| | - Usaku Reuben
- Department of Science Laboratory Technology, Modibbo Adama University, PMB 2076, Yola, Nigeria
| | - Patience U. Onyebuchi
- Department of Science Laboratory Technology, Modibbo Adama University, PMB 2076, Yola, Nigeria
| | | | - David Esenowo
- Department of Chemistry, Modibbo Adama University, PMB 2076, Yola, Nigeria
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Khan SA, Kojour MAM, Han YS. Recent trends in insect gut immunity. Front Immunol 2023; 14:1272143. [PMID: 38193088 PMCID: PMC10773798 DOI: 10.3389/fimmu.2023.1272143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/29/2023] [Indexed: 01/10/2024] Open
Abstract
The gut is a crucial organ in insect defense against various pathogens and harmful substances in their environment and diet. Distinct insect gut compartments possess unique functionalities contributing to their physiological processes, including immunity. The insect gut's cellular composition is vital for cellular and humoral immunity. The peritrophic membrane, mucus layer, lumen, microvilli, and various gut cells provide essential support for activating and regulating immune defense mechanisms. These components also secrete molecules and enzymes that are imperative in physiological activities. Additionally, the gut microbiota initiates various signaling pathways and produces vitamins and minerals that help maintain gut homeostasis. Distinct immune signaling pathways are activated within the gut when insects ingest pathogens or hazardous materials. The pathway induced depends on the infection or pathogen type; include immune deficiency (imd), Toll, JAK/STAT, Duox-ROS, and JNK/FOXO regulatory pathways. These pathways produce different antimicrobial peptides (AMPs) and maintain gut homeostasis. Furthermore, various signaling mechanisms within gut cells regulate insect gut recovery following infection. Although some questions regarding insect gut immunity in different species require additional study, this review provides insights into the insect gut's structure and composition, commensal microorganism roles in Drosophila melanogaster and Tenebrio molitor life cycles, different signaling pathways involved in gut immune systems, and the insect gut post-infection recovery through various signaling mechanisms.
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Affiliation(s)
- Shahidul Ahmed Khan
- Department of Applied Biology, Institute of Environmentally Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
| | - Maryam Ali Mohmmadie Kojour
- Life & Medical Sciences Institute (LIMES) Development, Genetics & Molecular Physiology Unit, University of Bonn, Bonn, Germany
| | - Yeon Soo Han
- Department of Applied Biology, Institute of Environmentally Friendly Agriculture (IEFA), College of Agriculture and Life Sciences, Chonnam National University, Gwangju, Republic of Korea
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